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Properties and Performance of Photocatalytic Concrete by Mahsa Heidari Dolatabadi A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Graduate Department of Civil Engineering University of Toronto © Copyright by Mahsa Heidari Dolatabadi 2013

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Page 1: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

Properties and Performance of Photocatalytic Concrete

by

Mahsa Heidari Dolatabadi

A thesis submitted in conformity with the requirements for the degree of Master of Applied Science

Graduate Department of Civil Engineering University of Toronto

© Copyright by Mahsa Heidari Dolatabadi 2013

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Properties and Performance of Photocatalytic Concrete

Mahsa Heidari Dolatabadi

Master of Applied Science

Graduate Department of Civil Engineering

University of Toronto

2013

Abstract

This research program is focused on the photocatalytic cement with emphasis on evaluating

impacts on concrete’s physical, transport and durability properties. The scope of this project is to

examine three key aspects of photocatalytic concrete including: a critical review of currently

reported applications; an examination of air pollution concentrations in Ontario to assess the

potential effectiveness of photocatalytic concrete, with respect to NOx; and an experimental

study to characterize the material properties.

Research findings revealed comparability between photocatalytic concrete and conventional

concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted

rapid freeze and thaw damage very well, in terms of de-icer salt scaling performance, only

formed surface performed well and highly variable results for photocatalytic and GU concrete

was observed for the finished surface.

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Acknowledgments

First and foremost, I would like to express my sincere appreciation to my supervisors, Professor

Daman Panesar and Professor Doug Hooton, for their guidance, support, and friendship. Most of

all, I would like to extend my gratitude to Professor Daman Panesar, who never ceased in

challenging me and sharing her precious time and positive insights, for offering me the research

assistant position and providing me with such a life changing experience. I am obliged for her

patience and encouragement during this project.

I also place on record my sincere thanks to Olga Perebatova, who has rendered aid above and

beyond the line duty. This project would not have been possible without her unconditional help

and support.

Also, I would like to take this opportunity and gratefully acknowledge:

The financial support provided by the Ministry of Transportation Ontario, the Natural

Sciences and Engineering Research Council of Canada (NSERC), and the Department of

Civil Engineering;

The material supply by Essroc Cement Corporation Canada, Euclid Concrete Admix, and

BASF Canada;

The technical support provided by talented Giovanni Buzzeo, Renzo Basset, and Bob

Manson;

The laboratory preparation and testing assistance provided by Benjamin Shindman,

Majella Anson-Cartwright, Ardavan Amirchoupani, and Eric Liu.

I am indebted to many people during my time at University of Toronto:

Majella, my best friend, mentor, officemate, for always being my rock! Without knowing

she was in my corner I could never have made it through;

Ardavan and Eric, my amazing officemates and partners in crime, for their assistance,

support, and being the best friends anyone could ask for;

The Concrete Materials Group for providing me with countless unforgettable memories

which I will cherish for the rest of my life.

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Finally, most important of all, from the depth of my heart, thanks to my dearest family:

My mom and dad for their moral and emotional support. Thank you for being so patient

with me during the though emotional times. Words cannot even begin to express my

gratitude for the strength you provided me with throughout the challenging moments;

My one and only sister, my bestie, my joy, Maral. Thank you for always being there to

listen to me ramble and offering me an oasis of solitude in the eye of the storm. Without

you, I truly am nothing;

My cousin, Maryam. You showed me how to dream, aim, find, and pursue a purpose in

my life. Thank you for always believing in me.

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Table of Contents

Properties and Performance of Photocatalytic Concrete ................................................................. i

Acknowledgments .......................................................................................................................... iii

Table of Contents ............................................................................................................................ v

List of Tables ................................................................................................................................. ix

List of Figures ................................................................................................................................ xi

Chapter 1 Introduction .................................................................................................................... 1

1.1 Background ......................................................................................................................... 1

1.2 Objectives and Scope .......................................................................................................... 2

Chapter 2 Literature Review ........................................................................................................... 4

2.1 TiO2 and Photocatalytic Concrete ....................................................................................... 4

2.2 Photocatalytic Mechanism .................................................................................................. 6

2.3 Properties ............................................................................................................................ 8

2.3.1 Self-cleaning ........................................................................................................... 8

2.3.2 De-polluting ............................................................................................................ 9

2.3.3 Other Properties .................................................................................................... 15

2.4 Applications ...................................................................................................................... 16

2.4.1 Field Studies .......................................................................................................... 17

Chapter 3 Potential Impacts of Photocatalytic Concrete on Air Quality in Ontario ..................... 20

3.1 Introduction ....................................................................................................................... 20

3.2 What is Smog? .................................................................................................................. 21

3.3 Air Quality in Ontario Cities ............................................................................................. 22

3.4 Pollution Fluctuations ....................................................................................................... 26

3.4.1 Hourly Trend ......................................................................................................... 26

3.4.2 Monthly Trend ...................................................................................................... 29

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3.5 Estimated Removal Efficiency ......................................................................................... 32

Chapter 4 Experimental Program ................................................................................................. 35

4.1 Introduction ....................................................................................................................... 35

4.2 Materials ........................................................................................................................... 35

4.2.1 Cementing Materials ............................................................................................. 35

4.2.2 Aggregate .............................................................................................................. 37

4.2.3 Chemical Admixtures ........................................................................................... 37

4.3 Phase I ............................................................................................................................... 38

4.3.1 Introduction ........................................................................................................... 38

4.3.2 Mix Design ............................................................................................................ 38

4.3.3 Mixing, Casting and Curing .................................................................................. 38

4.3.4 Testing Procedure ................................................................................................. 39

4.4 Phase II .............................................................................................................................. 40

4.4.1 Introduction ........................................................................................................... 40

4.4.2 Mix Design ............................................................................................................ 41

4.4.3 Mixing, Casting and Curing .................................................................................. 41

4.4.4 Testing Procedure ................................................................................................. 42

4.5 Phase III ............................................................................................................................ 44

4.5.1 Introduction ........................................................................................................... 44

4.5.2 Mix Design ............................................................................................................ 46

4.5.3 Mixing, Casting and Curing .................................................................................. 46

4.5.4 Testing Procedure ................................................................................................. 47

4.6 Phase IV ............................................................................................................................ 49

4.6.1 Introduction ........................................................................................................... 49

4.6.2 Mix Design ............................................................................................................ 50

4.6.3 Mixing, Casting and Curing .................................................................................. 50

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Chapter 5 Results and Discussion ................................................................................................. 51

5.1 Phase I ............................................................................................................................... 51

5.1.1 Compressive Strength ........................................................................................... 51

5.1.2 Porosity ................................................................................................................. 53

5.1.3 Effects of Paste Mix Design Variables – Phase I ................................................. 55

5.2 Fresh Concrete Properties ................................................................................................. 56

5.2.1 Phase II .................................................................................................................. 56

5.2.2 Phase III ................................................................................................................ 56

5.2.3 Phase IV ................................................................................................................ 57

5.2.4 Discussion of the Effects of Mix Design Variables .............................................. 58

5.3 Mechanical Properties ....................................................................................................... 59

5.3.1 Phase II .................................................................................................................. 59

5.3.2 Phase III ................................................................................................................ 62

5.3.3 Phase IV ................................................................................................................ 65

5.3.4 Discussion of the Effects of Mix Design Variables .............................................. 69

5.4 Transport Properties .......................................................................................................... 69

5.4.1 Phase II .................................................................................................................. 69

5.4.2 Phase III ................................................................................................................ 70

5.4.3 Phase IV ................................................................................................................ 72

5.4.4 Discussion of the Effects of Mix Design Variables .............................................. 74

5.5 Durability Properties ......................................................................................................... 74

5.5.1 Phase III ................................................................................................................ 74

5.5.2 Phase IV ................................................................................................................ 81

5.5.3 Effects of Mix Design Variables ........................................................................... 85

Chapter 6 Conclusion .................................................................................................................... 87

Chapter 7 Recommendations for Future Work ............................................................................. 89

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References ..................................................................................................................................... 90

Appendix A: Hourly Pollution Data for Toronto E Station .......................................................... 97

Appendix B: Monthly Pollution Data for Cities with the Greatest Number of Smog

Advisories in Ontario ............................................................................................................... 99

Appendix C: Pollution Conversion (ppb to mg/h/m2) ................................................................ 104

Appendix D: Test Data ............................................................................................................... 109

D.1 Phase II ............................................................................................................................ 109

D.2 Phase III ........................................................................................................................... 113

D.3 Phase IV .......................................................................................................................... 120

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List of Tables

Table 3.1: Air quality index range ................................................................................................23

Table 3.2: Limiting values for emissions in Ontario ....................................................................24

Table 3.3: Regions in Ontario with the highest smog advisories ..................................................25

Table 3.4: Station locations ...........................................................................................................26

Table 3.5: Percentage removal efficiency (%) ..............................................................................34

Table 4.1: Chemical composition of cementing materials ............................................................36

Table 4.2: Density of powder materials ........................................................................................37

Table 4.3: Mix design proportions (Phase I) .................................................................................39

Table 4.4: Mix design proportions (Phase II) ...............................................................................41

Table 4.5: Fresh concrete properties tests .....................................................................................42

Table 4.6: Mechanical properties tests ..........................................................................................43

Table 4.7: Mix proportions used for the foam index test method .................................................45

Table 4.8: Mix design proportions (Phase III) ..............................................................................46

Table 4.9: Transport properties tests .............................................................................................47

Table 4.10: Durability properties tests ..........................................................................................48

Table 4.11: Mix design proportions (Phase IV) ............................................................................50

Table 5.1: Strength and porosity assessments (Phase I) ...............................................................52

Table 5.2: Fresh properties of plastic concrete (Phase II) .............................................................56

Table 5.3: Fresh properties of plastic concrete (Phase III) ...........................................................57

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Table 5.4: Fresh properties of plastic concrete (Phase IV) ...........................................................57

Table 5.5: Air content characterization (Phase III) .......................................................................64

Table 5.6: Air content characterization (Phase IV) .......................................................................67

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List of Figures

Figure 2.1: TiO2 reaction process ...................................................................................................5

Figure 2.2: Photocatalytic mechanism ............................................................................................7

Figure 2.3: Photocatalytic conversion of NOx to HNO3 .................................................................8

Figure 2.4: effects of flow rate and relative humidity on NOx reduction efficiency ....................10

Figure 2.5: Dynamic method, fixed [NO] .....................................................................................13

Figure 2.6: abrasion and wear resistance properties of TiO2 ........................................................16

Figure 3.1: Windsor DT O3 hourly data from May to Sept ..........................................................27

Figure 3.2: Windsor DT NOx hourly data from May to Sept .......................................................27

Figure 3.3: Windsor DT O3 hourly data from Oct to April ...........................................................28

Figure 3.4: Windsor DT NOx hourly data from Oct to April ........................................................28

Figure 3.5: O3 monthly data for regions in Ontario with the highest smog advisories ................30

Figure 3.6: NOx monthly data for regions in Ontario with the highest smog advisories ..............31

Figure 3.7: Average monthly NO concentration (mg/h/m2) .........................................................33

Figure 3.8: Average monthly NO concentration for Toronto (mg/h/m2) .....................................33

Figure 4.1: Mix#1 and Mix#2 before addition of AEA solution (left), foam on the surface after

addition of AEA and shaking for 45s (right) ................................................................................45

Figure 5.1: Strength of samples (Phase I) .....................................................................................53

Figure 5.2: Porosity of samples (Phase I) .....................................................................................54

Figure 5.3: Porosity vs. Strength ...................................................................................................55

Figure 5.4: Air content vs. Slump .................................................................................................58

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Figure 5.5: Compressive strength of concrete (Phase II) ..............................................................60

Figure 5.6: Density of concrete (Phase II) ....................................................................................60

Figure 5.7: Ultrasonic pulse velocity (Phase II) ...........................................................................61

Figure 5.8: Air content (Phase II) .................................................................................................61

Figure 5.9: Compressive strength of concrete (Phase III) ............................................................62

Figure 5.10: Density of concrete (Phase III) .................................................................................63

Figure 5.11: Ultrasonic pulse velocity (Phase III) ........................................................................63

Figure 5.12: Air content (Phase III) ..............................................................................................65

Figure 5.13: Compressive strength of concrete (Phase IV) ..........................................................66

Figure 5.14: Ultrasonic pulse velocity (Phase IV) ........................................................................66

Figure 5.15: Air content of concrete (Phase IV) ...........................................................................68

Figure 5.16: Influence of air content on compressive strength (28d) ...........................................68

Figure 5.17: Rapid chloride permeability of concrete (Phase II) ..................................................69

Figure 5.18: Rapid chloride permeability of concrete (Phase III) ................................................70

Figure 5.19: Initial sorptivity of finished and formed surface concrete at 28 days (Phase III) ....71

Figure 5.20: Initial sorptivity of finished and formed surface concrete at 56 days (Phase III) ....71

Figure 5.21: Rapid chloride permeability of concrete (Phase IV) ................................................72

Figure 5.22: Initial sorptivity of finished and formed surface concrete at 28 days (Phase IV) ....73

Figure 5.23: Influence of air content on RCPT result at 28d ........................................................73

Figure 5.24: Salt scaling mass loss of finished surface (Phase III) ...............................................76

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Figure5.25: Salt scaling mass loss of formed surface (Phase III) .................................................76

Figure 5.26: GU concrete (finished surface) after 50 freeze-thaw cycle (Phase III) ....................77

Figure 5.27: PH concrete (formed surface) after 50 freeze-thaw cycle (Phase III) ......................77

Figure 5.28: GU concrete (formed surface) after 50 freeze-thaw cycle (Phase III) .....................78

Figure 5.29: PH concrete (formed surface) after 50 freeze-thaw cycle (Phase III) ......................78

Figure 5.30: Durability factor after 300 rapid freeze-thaw cycles (Phase III) ..............................79

Figure 5.31: GU and GU+25%GGBFS prisms after 300 rapid freeze-thaw cycles (Phase III) ...80

Figure 5.32: PH and PH+25%GGBFS prisms after 300 rapid freeze-thaw cycles (Phase III) ....80

Figure 5.33: Salt scaling mass loss of finished surface (Phase IV) ..............................................82

Figure 5.34: Salt scaling mass loss of formed surface (Phase IV) ...............................................82

Figure 5.35: GU concrete (finished surface) after 50 freeze-thaw cycle (Phase IV) ....................83

Figure 5.36: PH concrete (finished surface) after 50 freeze-thaw cycle (Phase IV) ....................83

Figure 5.37: GU concrete (formed surface) after 50 freeze-thaw cycle (Phase IV) .....................84

Figure 5.38: PH concrete (formed surface) after 50 freeze-thaw cycles (Phase IV) ....................84

Figure 5.39: Influence of air content on salt scaling for finished surface after 50 cycles ............85

Figure 5.40: Influence of air content on salt scaling for formed surface after 50 cycles ..............86

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Chapter 1 Introduction

1.1 Background

Photocatalytic concrete is an innovative advancement in material science that enables the

photocatalytic phenomenon to occur within the building material itself and has good potential to

reduce airborne pollutants such as sulfur oxide (SOx), particulate matter (PM10), volatile organic

compounds (VOCs), and nitrogen oxide (NOx). Photocatalysis is a process that uses the power

of the ultraviolet (UV-A) portion of sunlight to accelerate the natural oxidation process to

decompose pollutants. In the past decade, photocatalytic technologies have been applied to

glass, ceramic, and cement-based materials. The photocatalytic mechanism is not new, in fact

the process has been understood and applied since the 1960s (Fujishima et al., 2000). There has

been considerable focus on water treatment technologies, but the application of photocatalytic

oxidation to construction materials has been gaining attention since the 1990s. More recently,

photocatalysis has been integrated directly into construction building materials. Its effectiveness

as a sustainable option is currently being assessed through pilot studies in France, Italy, the

Netherlands, and Japan. Photocatalytic concrete is also known as smog-eating and self-cleaning

concrete because it assists in air pollution reduction (Essroc Italcementi Group, 2009).

Environmental pollution has raised global attention of the need to implement environmentally

friendly technologies and practices. Industry flue gases, local traffic and diesel engines play

major roles in generating emissions like volatile organic compounds (VOCs), hydrocarbons that

have evaporated from chemical plants; nitrogen oxides (NOx) produced primarily by internal

combustion engines; and sulphur oxides (SOx) formed when fuel such as coal and oil is burned

(Hassan, 2010). NOx (NO and NO2) is responsible for ozone and particulate build-up through

photochemical reactions with hydrocarbon (Barbesta and Schaffer, 2009). Due to these highly

reactive gases, there are a variety of health and environmental impacts such as urban smog and

acid rain, which harms forests, crops and aquatic life. Since the passage of the Clean Air Act in

1970, in the United States, the concentration of principal air pollutants, except NOx, have

decreased (Hassan, 2010).

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Thus, NOx emissions have been a focus of environmental regulations and can be controlled by

two different approaches: the reduction of NOx back to molecular nitrogen (N2), or its oxidation

to nitrogen dioxide (NO2) and nitric acid (HNO3). For example, the oxidation of nitric acid

completes the nitrogen fixation and has useful applications such as in fertilizers. Many organic

compounds and air pollutants can be decomposed by ultraviolet radiation but this process is

extremely slow. The conversion of NOx to low concentrated nitrates makes this pollutant

compound soluble in water, which can be flushed away by rain. This type of photochemical

conversion is called photocatalytic oxidation (PCO) (Husken, 2009).

The sun can provide up to 3×1024

J of energy per year, which is 10,000 times more than the

whole world’s annual energy consumption (Butcher et al., 1992). The fact that many

compounds of air pollutants such as NOx and SOx can be decomposed by ultraviolet radiation

has led to the exploration of the uses of solar energy in context with building materials

(Diamanti et al., 2008).

Photocatalytic materials contain nano-particles of titanium dioxide (TiO2); that can accelerate

the oxidation and decomposition of organic and inorganic compounds in the presence of

sunlight. Photo means light and catalysis is the process that accelerates the rate of reaction

without being consumed (TioCem, 2010). TiO2 has the ability to enhance the durability of

concrete by accelerating the breakdown of organic pollutants and micro-organisms to help

reduce concrete discoloration and deterioration. It can be applied to water and cement to act as

purification when used as a catalyst, which can be activated with the UV-A part of sunlight

(Ballari et al., 2009).

1.2 Objectives and Scope

The intent of this study is to test photocatalytic concrete properties and long-term performance.

This study also examines its potential pollution abating effectiveness in Ontario. The potential

usage of photocatalytic concrete cannot solely be based on its benefits related to pollution

degradation; a complete evaluation of its durability is required as well as other critical factors

that need to be considered in selecting environmentally friendly building materials. There is a

current need for improved materials and evaluation of crucial parameters that influence and

impact the physical and mechanical properties of the photocatalytic concrete.

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The scope of this research is:

To conduct a detailed literature review.

To conduct a laboratory experimental program to characterize the mechanical, transport

and durability properties of photocatalytic concrete in comparison with conventional

concrete.

To examine high pollution regions in Ontario (including Toronto) and assess the

interplay between pollutant concentrations.

To identify regions where photocatalytic concrete infrastructure has the potential to be

most effective based on the experimental results and the literature reported ranges for

NOx abatement rates.

To reveal the influence of environmental conditions, particularly temperature, on the

photocatalytic pollution degradation mechanism in order to develop a correlation

between photocatalytic effectiveness and seasonal climate.

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Chapter 2 Literature Review

2.1 TiO2 and Photocatalytic Concrete

Titanium is the world’s fourth most abundant metal and the ninth most abundant element,

constituting about 0.63% of the Earth’s crust (Carp et al., 2004). TiO2 is a semiconductor, non-

toxic, and chemically stable material. It can be crystallized into three different molecule

structures: rutile, anatase, and brookite. Rutile is used as a pigment for relatively white paints

with low photocatalytic reactivity. Both the anatase and rutile forms act similarly in

photocatalysis (Hunger et al., 2008). Anatase is preferable due to its high reactivity (Pacheo-

Torgal and Jalali, 2011).

TiO2 can be integrated in the cement manufacturing process to produce photocatalytic cement.

Normal daylight can be used for the photocatalytic reaction (Beeldens, 2006). When this type of

cement is used in concrete structures, a charge is created on the surface that reacts with external

substances to decompose air pollutants such as NOx (Chusid, 2006). TiO2 can be integrated

within the concrete pavement surface to act as an accelerator of a natural oxidation process. It

promotes faster decomposition of NOx and SOx from the air. (Essroc Italcementi Group, 2008).

As shown in Figure 2.1, when TiO2 is activated by UV light, in a catalytic reaction it first breaks

down NOx gases into nitric acid (HNO3) that then adhere to water droplets. These water droplets

will then be washed away by rain. Photocatalytic effect is associated with a reduced nitric oxide

(NO) oxidation to nitrates and these ions are flushed from the surface as a weak HNO3. The

whole reaction results in a significant reduction in the concentration of pollutants from the

atmosphere when used on or in a concrete structure that is exposed to UV-A and placed close to

the pollution source (Hassan, 2010).

For pavement block applications, since PCO turns the pollutants into water soluble compounds,

the porosity of the block is very important in the ability to remove NO, and an increase in the

porosity will promote pollution removal. The porosity is affected by aggregate size, water-to-

cement ratio, and, in general, the mix design of the concrete (Poon and Cheung, 2007).

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The presence of light, which is in direct contact with the pavement surface, is also a significant

factor (Ballari et al., 2010). This is a promising approach for self-cleaning surfaces and for

solving the environmental problem, such as air pollution, by degradation of NOx (Poon and

Cheung, 2007).

Figure 2.1: TiO2 reaction process (TioCem, 2010)

Some of the applications of TiO2 nano-particles in the construction industry include self

cleaning, air cleaning, acting as an anti-bacterial, and anti-fogging (Pacheo-Torgal and Jalali,

2010). The study of photocatalytic technology started as a treatment for water polluted with

toxic substances and has become this technology’s main task. Recently, commercial products

such as anti-fog products for mirrors and glasses, anti-bacterials, fibres, water purifiers, self-

cleaning items such as car coatings, and construction materials have incorporated TiO2 (Essroc

Italcementi Group, 2009). In the past decade, Europeans have started implementing the self-

cleaning benefits of photocatalytic concrete technology on building surfaces, which allows

maintaining an unaltered aesthetic appearance over time (Cassar et al., 2007).

More recently, photocatalysis has been applied as a coating on the surface of buildings and

pavements for its de-polluting effect rather than for self-cleaning. Similar projects have been

launched in the European and American market with the aim of having a positive impact on

urban air quality (Ircelyon, 2010). Hassan (2009) showed through a life cycle assessment (LCA)

that a TiO2 coating will have an overall positive effect on the environment. An LCA is an

investigation and evaluation of all the environmental impacts of a given product for every stage

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of its existence, including material extraction and processing, manufacturing, transportation,

use, and disposal. Since photocatalytic concrete is a fairly new technology, its structural

properties and functional characteristics are not fully uncovered. Further research and studies

are required in order to demonstrate the benefits of this innovative (Crispino and Lambrugo,

2007).

2.2 Photocatalytic Mechanism

TiO2 is the primary photocatalytic ingredient and studies have shown that TiO2 incorporated

into building materials can keep surfaces clean (surface-cleaning) and significantly reduce

smog-forming air pollutants (pollution abatement) (Italcementi, 2008).

The photocatalytic mechanism required for TiO2 to degrade pollutants is illustrated in Figure

2.2. As soon as a TiO2 surface is exposed to UV light, two types of photochemical reactions

occur: photo-induced redox reactions of the absorbed pollutants and photo-induced hydrophilic

conversion. When TiO2 absorbs UV-A radiation from sunlight or an illuminated light source

such as a fluorescent lamp, it will produce pairs of electrons and holes. In the presence of light,

the electrons become excited and produce energy. The photo-produced holes represent stored

energy. The excess energy creates the negative-electron (e-) and positive-hole (h+) pair (Gens

Nano, 2011). With water and UV light present, the electron hole reacts with the OH-group from

adsorbed water, generating hydroxyl radicals and charged species at the surface of the catalyst

(Husken et al., 2009).

During this encounter, an OH- group loses an electron and highly reactive hydroxyl radicals can

form. Such radicals react with airborne pollutant molecules that are adsorbed by the particle’s

surface. These reaction products remain on the surface until they are fully oxidized (Gens Nano,

2011).

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Figure 2.2: Photocatalytic mechanism (Gens Nano, 2011)

In addition, the reducing power of the electrons can induce the reduction of molecular oxygen

(O2) to superoxide (O2-). This is as effective as the holes and hydroxyl radicals in the chain

reactions for breaking down organic compounds (Beeldens, 2006). Figure 2.3 demonstrates the

photocatalytic conversion of NO, which leads to the formation of weak nitric acid HNO3. Most

cement formulations are alkaline, which neutralizes HNO3. As shown in Equations 2.1 to 2.3,

acid reacts with calcium carbonate, locking the NOx gases up in calcium nitrate and releasing

CO2 and water (Chen and Poon, 2009).

𝑁𝑂 + 1 2 𝑂2 → 𝑁𝑂2 (2.1)

2𝑁𝑂2 + 12 𝑂2 + 𝐻2𝑂 → 2𝐻𝑁𝑂3 (2.2)

𝐻𝑁𝑂3 + 𝐶𝑎𝐶𝑂3 ↔ 𝐶𝑎(𝑁𝑂3)2 + 𝐻2𝑂 + 𝐶𝑂2 (2.3)

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Figure 2.3: Photocatalytic conversion of NOx to HNO3 (Chen and Poon, 2009)

2.3 Properties

2.3.1 Self-cleaning

The self-cleaning effectiveness of photocatalytic concrete is a function of the TiO2 content of the

cement as well as TiO2 particle size. Pacheo-Torgal and Jalali (2011) demonstrated that higher

TiO2 content in cement increases the self-cleaning activity in the photocatalytic cement paste in

comparison to cement mortars. Folli et al. (2010) studied the effect of TiO2 particle size on self-

cleaning by investigating the degradation of Rhodamine B (RhB). The study found that mortars

made with 100% anatase microsized (m-TiO2) with a particle size of 154 ± 48 nm showed

higher self-cleaning results than nanosized (n-TiO2) mortar with a particle size of 18 ± 5 nm.

This is due to the fact that the m-TiO2 had a high surface area of 8.7 m2/g for RhB absorption

and a very low rate for recombination of photo-produced holes in the particle volume.

Furthermore, both m-TiO2 and n-TiO2 tend to overcharge the surface in high pH conditions, but

m-TiO2 dispersion is better due to its relatively smaller agglomerates and relatively larger pores

(Folli et al., 2010).

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2.3.2 De-polluting

Berdahl and Akbari (2008) investigated the de-polluting rate of photocatalytic concrete consist

of cement that included about 1% to 5% anatase TiO2 nano-particles. The results determined

that 1 m2 of TiO2 catalytic surface can clean up to 200 m

3 of NOx and about 60 m

3 of VOCs per

day.

Folli et al.’s (2010) study on the influence of TiO2 particle size on the photocatalysis pollution-

abating ability was conducted with the use of oxidation of gaseous NOx in the photocatalytic

reactor. The study found that 100% anatase n-TiO2 mortar showed higher activity rather than m-

TiO2. NOx particles can easily penetrate and since n-TiO2 clusters had a higher available

specific area of 78.9 m2/g, incorporation of n-TiO2 will enhance the de-pollution property (Folli

et al., 2010).

An increase in the curing age as well as surface carbonation results in a decrease in the NOx

removal efficiency of the TiO2 contained concrete. With an increase in curing time, the

hydration products will increase, filling up the capillary pores and resulting in the development

of diffusion barriers to both reactants and photons (Chen and Poon, 2009).

It has been found that porosity and surface roughness of the TiO2 cementitious materials affect

their air-cleaning potential (Ramirez et al., 2010). In a review of nanotechnology, Pacheo-Torgal

and Jalali (2011) mentioned that there is higher reduction in NOx by TiO2 cementitious

composites that have high surface porosity. Furthermore, the type of surface finishing treatment

can influence the active surface area, and shot-blasted paving block has higher rates of

photocatalytic reaction at the surface in comparison to untreated paving block due to the

increase in surface area (TioCem, 2010).

The impacts of common roadway contaminants on the photocatalytic reaction (NOx removal

ability) and surface porosity of the top photocatalytic concrete layer over road pavements were

examined by Dylla et al. (2011). The impacts of three contaminant types on the NOx removal

efficiency, namely, dirt, motor oil, and de-icing salts were investigated. The results show that oil

has the worst impact. In addition, as demonstrated in Figure 2.4, the study showed that the flow

rate of the contaminants as well as lower relative humidity impact the removal efficiency. A

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lower flow rate and lower humidity are favourable for increasing the rate of NOx removal of

photocatalytic layer (Dylla et al., 2011).

Figure 2.4: Effects of flow rate and relative humidity on NOx reduction efficiency (Dylla et

al., 2011)

Furthermore, Asadi et al. (2012) conducted a field study to investigate the parameters that

influence the removal efficiency of the photocatalytic asphalt pavement. The results indicate

that the maximum NOx removal efficiency of the TiO2 ranges from 34% to 62%. In addition, it

has been found that an increase in relative humidity and flow rate will decrease the NOx removal

efficiency of the photocatalytic-pervious concrete (Asadi et al., 2012).

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The de-polluting efficiency of the TiO2-containing concrete blocks made out of local waste

materials such as recycled aggregate (RA) and crushed recycled glass cullet were examined in

Poon and Cheung’s 2007 study. This efficiency was then compared with the natural TiO2-

containing concrete as well as the influence of particle size in each case. A smaller amount of

fine particles leads to a higher porosity for the surface layer. The study demonstrated that lower

cement to aggregate ratio would result in a higher NO removal efficiency. The samples were

tested at different curing ages and the results show that the removal efficiency would be

stabilized after an initial decrease, which happens in the first 90 days (Poon and Cheung, 2007).

2.3.2.1 Measurement and Mathematical Modeling

Several studies have investigated modelling to determine the de-polluting efficiency of

photocatalytic concrete. For example, the NOx flow-through method is described in Japanese

standard JIS TR Z 0018 (Cassar et al., 2007). For this test, a TiO2 paving block 100×200 mm2 is

placed in water under a UV-transparent glass plate in a metal container while the surface of the

sample is exposed to air with a NO concentration of 1 parts per million (ppm) by volume at a

flow rate of 3 litre per minute (L/min), all while under controlled humidity and temperature. The

NO removal efficiency is a function of temperature, relative humidity and contact time. The

efficiency is measured based on a comparison between the inlet and outlet concentration of the

pollutants as well as the NO3- concentration of the water, in which the sample is immersed

(Cassar et al., 2007). Chen and Poon (2009) calculated the amount of NOx removal QNO x (µmol

m-2) based on a similar testing procedure that complies with the ISO standard 22197-1:

QNO x=

f

22.4 NO 0− NO dt− ( NO 2 − NO 2 0)dt

A×T (2.4)

Where NO 0 and NO are, respectively, the inlet and outlet concentration of NO, NO2 0 and

NO2 are, respectively, the inlet and outlet concentration of NO2 , t is the removal operation

time, A is the sample surface area (m2), f is the flow rate (L/min) , and T is the duration of

photocatalytic process. The constants were the UV-A intensity 0.6 ± 0.1 (w/m2), a temperature

of 50ºC, and 30% relative humidity (Chen and Poon, 2009).

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The dynamic method, with a fixed concentration of NO, is also used to assess the de-polluting

efficiency (Cassar et al., 2007). The test apparatus consists of the reactor, which allows a sample

of size 100×200 mm2; a light source with a UV-A radiation range of 300 to 400 nm; a testing

gas supply restraining two stages of gas flows, polluted and transport fluid, with a flow volume

of 3 L/min; and an analyzer to measure concentrations at 5-second intervals. Based on this test

set-up, a model is derived to explain the reaction process in the reactor (Hunger and Brouwers,

2009).

The degradation of NO is illustrated in Figure 2.5 and can be measured by the NOx reduction

percentage Q (Cassar et al., 2007):

Q = 1 − NO out

NO in × 100 (2.5)

There are several stages in the conversion of NOx including the mass transfer from gas to

catalyst surface, absorption by the surface, a photochemical reaction on the surface, desorption

from the surface, and then a mass conversion into the fluid at the surface of the concrete (Zhao

and Yang, 2003). The conversion rate at the surface should not be ignored because the

degradation rate is much lower than the diffusion rate (Hunger et al., 2010).

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Figure 2.5: Dynamic method, fixed [NO] (Husken et al., 2009)

It should be noted that only absorbed NO can be oxidized. In order to express this adsorption

process, the Langmuir equation is used (Zhao and Yang, 2003):

θ =μmax Ka C

1+ Ka C (2.6)

where θ is the adsorbed NO amount per gram of the catalyst, μmax

is the maximum amount of

compounds adsorbed on the catalyst surface, Ka is the adsorption equilibrium constant, and C is

the concentration of the contaminants in the gas phase. The degradation influencing factors

include light intensity, reactant concentration, oxygen concentration, water vapour content, and

temperature (Zhao and Yang, 2003). At different reaction times, the photocatalytic activity of

nitrogen oxide reduction, AF (m·h-1), can be calculated as follows:

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AF = (CLight Off − CLight On )

CLight Off ×

Q

S× I (2.7)

where C is the concentration of NOx, NO2, and NO at equilibrium, S is the geometrical surface

area, and I is the intensity of the luminous flux in W/m2. Overall, the de-polluting efficiency will

increase if the contact time is longer, the temperature is higher, and the relative humidity is

lower (Cassar et al., 2007).

Aside from the direct monitoring of NO reduction of the air, there is an indirect technique to

measure the NOx reduction by the photocatalytic process. This is done by measuring the

deposited nitrate salts (NO3) on the surface of the photocatalytic material (Beeldens, 2008).

Since nitrates are soluble in water, NO3 is collected from the sample by washing the surface.

The collected NO3 is then converted into NO2 by utilizing a colorimetric method of cadmium

reduction, based on EPA Method 353.2, in order to measure the NO3 concentration (Osborn et

al., 2012).

Knowing the nitrate concentration, the volume of NO contaminant in litres can be calculated by

Equation 2.8:

Vcontaminant = Mass Contaminent (g)

Molecular Weight contaminant (g

mol) × 8.3144

L.kPa

mol .K × Tair ×

1

Pair (kPa ) (2.8)

where 𝑇 and 𝑃 are the air temperature and pressure, respectively (Osburn et al., 2012).

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2.3.3 Other Properties

Nazari and Riahi (2011) investigated the effects of TiO2 on the physical and mechanical

properties of concrete that contained 45% ground granulated blast furnace slag (GGBFS) as a

binder. The addition of GGBFS improves workability and decreases water demand, as it

increases the paste volume due to the lower relative density of slag (Hinczak, 1990). The study

examined the flexural strength, the pore structure by mercury intrusion porosimetry (MIP), X-

ray diffraction (XRD), scanning microscopy (SEM), and heat of hydration and mass loss of the

specimens by thermo-gravimetric analysis (TGA). The results showed that the addition of up to

3% TiO2 nano-particles by mass could increase the flexural strength, improve the pore structure

and dispersion of the particles, and progress the formation of hydrated products (Nazari and

Riahi, 2011).

Studies have investigated the early hydration behaviour of C3S pastes with the addition of TiO2.

Results showed that the rate of hydration increased with addition of chemically non-reactive

TiO2 particles due to decrease in particle size (Jaypalan, 2010). However, Lee and Kurtis’s

(2010) study showed that hydration acceleration occurs only with 10% to 15% TiO2 pastes,

while the hydration is delayed with 5% TiO2 paste. The compressive, tensile and flexural

strengths of the cement mortar incorporating TiO2 were investigated in an attempt to provide a

relationship between the TiO2 powders’ particle size and mechanical properties mortars

(Kawakami et al., 2007).

In terms of durability, a study was conducted on a TiO2 concrete coating using SEM and energy

dispersive spectroscopy (EDS) to determine the effects of wearing abrasion and wearing by a

loaded-wheel tester (LWT) and rotary abrasion (RA) on the distribution of TiO2 particles on the

surface (Hassan et al., 2010). The results show that NOx removal efficiency depends on the

contaminant flow rates, air humidity, mix design of the coating, ambient temperature, and TiO2

content. Overall, the coating with 5% TiO2 was the most efficient in terms of the NO removal.

As shown in Figure 2.6, after undergoing LWT and RA, there was a slight reduction in the rate

of removal for the 5% TiO2 sample, whereas the sample with 3% TiO2 showed better removal

efficiency after LWT than to RA. Furthermore, EDS results showed that there was no

considerable change in the concentration of TiO2 (Hassan et al., 2010).

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Figure 2.6: Effect of abrasion and wear resistance on NOx removal efficiency of TiO2

(Hassan et al., 2010)

2.4 Applications

There are various applications for photocatalytic materials in the construction industry. These

applications range from self-cleaning facades to solar reactors for wastewater treatments. TiO2

can be used both as an additive in concrete and as paint for coating. The goal is to have as much

TiO2 as possible at the surface of the material (Beeldens, 2006).

In the construction industry, actual applications of TiO2 nano‐particles in concrete are minimal

and are typically reserved for those fabricated bi‐layer concrete systems with a relatively high

unit price. The reason for this is that TiO2 nano‐particles are expensive in relation to concrete,

especially in the large volumes that are normally used to build concrete structures. Typical

examples of products currently found are special concrete blocks, bricks, tiles or roof tiles where

the TiO2 is applied as a top‐layer or coating (Broekhuizen et al., 2010).

The effectiveness of the photocatalytic oxidation reactions is related to the area of the

photocatalytic surface exposed to air and sunlight, allowing a variety of possible applications for

cement-based photocatalytic materials in horizontal applications, such as concrete pavements

and roofing tiles; on vertical applications, such as in paints, renderings, concrete panels, and

sound-absorbent elements for buildings and roads; and in tunnels that are equipped with UV-A

lamps (Cassar et al., 2007).

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2.4.1 Field Studies

Although environmental and operational variables complicate the assessment of field NOx

reduction, various field studies have been done to quantify NOx reduction and to confirm the

results from pilot and laboratory studies:

Italcementi Group (2008) installed a thin layer of photocatalytic mortar on an asphalt road in

a heavily travelled (over 1000 vehicles/hour) two-way road in the Segrate area of Milan as

their first photocatalytic experiment. The results, which were dependent on light intensity,

relative humidity, pollution concentration, and wind speed and direction, showed up to 60%

improvement in NOx abatement with the best results achieved during a light intensity of

90,000 lux, temperature of 32ºC, relative humidity of 46%, and wind speed of 0.7 m/s

(Italcementi, 2008).

Another project by Italcementi Group was conducted in Paris, France. For this project, a

photocatalytic concrete overlay was placed on a 6,000 m2

section of the street that was

traveled by more than 13,000 cars. Results showed an initial pollution decrease of at least

20% (Italcementi, 2008).

During the restoration of the Umberto tunnel in Rome, Italy in 2007, 9,000 m2 of the tunnel

was covered in a photocatalytic cementious paint called CIMAX Ecosystem. The results

indicated about a 20% NOx reduction (Italcementi, 2008). Another tunnel application of

photocatalytic material was done in in Milan, Italy on Porpora Street, which is traversed by

30,000 vehicles/day. This time, both the road pavement and the tunnel ceiling were covered

by cast-in-place photocatalytic concrete pavement and a non-cementitious photocatalytic

paint treatment, respectively. Under the low intensity light conditions, results showed close

to 23% lower NOx reduction compared to usual light intensity levels (Italcementi, 2008).

The Belgian Road Research Centre (BRRC) studied the application of 10,000 m2

photocatalytic concrete on the side roads of a main entrance axis in the city of Antrep

(Beeldens, 2006). Results from on-site the indirect technique to evaluate NOx degradation

measurements revealed a decrease in the pollution peaks. This confirmed the laboratory

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results, which showed evidence of reduction efficiency over time due to the surface

deposition of NO3 (Beeldens, 2006).

The Photocatalytic Innovative Coverings Applications for Depollution Assessment

(PICADA) research group project was partially funded by the European Union and

comprised of companies and universities from many European countries. It started on

January 2002 and ended in 2005, and its goal was “to develop a range of photocatalytic

materials and to evaluate their effect at a large scale, typically street canyons” (PICADA,

2010). Results for NOx abatement varied from 20% to 80% depending on wind conditions.

There have been different projects to test the effectiveness of photocatalytic coating on noise

barriers. An air quality innovation program performed in the Netherlands showed no

evidence that a coating of titanium dioxide on noise barriers removes harmful NOx emissions

from the air. Several explanations were suggested for the disappointing results: short contact

time between the air and the barrier, relatively unfavourable weather conditions because of

the direction of the wind and light intensity, high relative humidity of 55% to 95%, and

frequent low temperatures (IPL, 2009).

Another noise barrier project in France to evaluate the in situ effectiveness of a unique

coating system of NOxer, a coating system for vertical structures, on noise barrier walls. The

air pollution levels were monitored at different measurement stages to isolate the catalytic

effects from the other variables. Results showed a reduction of 10% to 15% in the immediate

vicinity of the wall on both sides (IRF, 2010).

In Tokyo, two types of photocatalytic noise barrier panels, an open panel and a windowed

panel, were placed alongside a heavy traffic (113,000 vehicles per day) highway. The

windowed panel had a glass covering and air was pumped into contact with the

photocatalytic surface. The reported average percentage removal of NOx for the windowed

panel was 31% to 69% (Berdahl and Akbari, 2007).

In the United States, the first field installation of photocatalytic pavement was studied by

Asadi et al. (2012) to evaluate the field efficiency of photocatalytic asphalt pavement as well

as the effects of different operational parameters on NO degradation. For this project, a

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water-soluble nano-TiO2 solution was sprayed on a section of asphalt pavement in Baton

Rouge, LA. Results from the hourly comparison of the NO measurements before and after

the TiO2 application show reduction efficiencies of 16% to 90%. Furthermore, based on

their parametric study, it was shown that the most effective factors on photocatalytic

oxidation were traffic level, relative humidity, and solar radiation, while in-service operating

conditions did not contribute to the reduction of the photocatalytic ability (Asadi et al.,

2012). Aside from ambient air monitoring technique, Dylla et al. (2012) utilized the indirect

technique to evaluate NOx degradation at the same location. The indirect method values

were lower than the direct method “since not all of the nitrates were eluted in the time

allowed for the sample collection” (Dylla et al., 2012). Results show that both direct and

indirect methods for the NOx degradation measurements confirm that the photocatalytic

reactions occur in the field and are influenced by environmental factors such as relative

humidity, wind speed and direction, light intensity and solar radiation (Dylla et al., 2012).

Osborn et al. (2012) studied the air-purifying asphalt and concrete photocatalytic pavement

site located on Louisiana State University campus. The spray coating used was a mixture of

aqueous TiO2 anatase nanoparticles. The indirect field measurement was done to evaluate

the photocatalytic NO degradation by measuring deposited nitrate salts on the pavement

surface. The results confirmed that the operating conditions had negligible effects on the

efficiency of the photocatalytic process and this process had the highest activity during the

first four days of the installation (Osborn et al., 2012).

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Chapter 3 Potential Impacts of Photocatalytic Concrete on Air Quality in

Ontario

3.1 Introduction

An examination of the potential beneficial impacts of photocatalytic concrete on air quality in

Ontario warrants knowledge of (i) cities with the poorest air quality and their corresponding

pollution levels, and (ii) the abating efficiency of photocatalytic concrete. Ontario air quality

data is documented by the Ministry of the Environment Ontario (2012) at

www.airqualityontario.com. The range of pollution-abating effectiveness of photocatalytic

concrete reported in the literature varies widely for both laboratory studies and field

applications. Literature reports show that implementing a photocatalytic concrete cover or a

photocatalytic coating can reduce NOx concentrations by up to 80% (PICADA, 2010). At the

same time, some studies have shown that the photocatalytic applications reduce NOx levels by

only 20% (PICADA, 2010). The wide range of abatement efficiencies is strongly linked to the

sensitivities of the photocatalytic processes to environmental conditions such as irradiance,

wind, relative humidity and temperature (Churchill and Panesar, 2012). Awareness of daily and

annual pollution level fluctuations in the absence of photocatalytic processes is necessary to be

able to adequately interpret any reduction in pollution as a result of photocatalysis in field

applications. This chapter will:

Identify Ontario cities with the poorest air quality based on approximately 11 years of

reported pollution data from the Ministry of the Environment Ontario website

(www.airqualityontario.com).

Examine hourly and monthly trends in pollution fluctuations and measurements.

Estimate the potential pollution reduction for two scenarios; the first scenario reflects the

case where photocatalytic concrete exhibits a relatively low rate of abatement, and the

second scenario will assume a relatively high rate of abatement.

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Outcomes from this section are anticipated to provide insight regarding optimum applications

and locations for photocatalytic concrete. In addition, the results will also emphasize the

importance for natural daily and seasonal pollution fluctuations that must be considered when

measuring field pollution data in efforts to quantify pollution reductions as a result of

photocatalysis.

3.2 What is Smog?

Smog, or smoky fog, is the result of series of complex photochemical and chemical reactions

that happen during lack of dispersion due to insufficient atmospheric turbulence. The main

components of smog are ground-level ozone (O3) and fine particulate matter (PM2.5) (Piver,

1987).

As mentioned in chapter 2, NOx (NO and NO2) is responsible for ozone and particulate build-up

through photochemical reactions with hydrocarbon (Barbesta and Schaffer, 2009). Thus, O3 is a

result of photochemical reaction of NOx and VOCs; Photo-dissociation of nitrogen dioxide

(NO2) into nitric oxide (NO) and oxygen free radicals which reacts with abundant oxygen

resulting in formation of O3 (Piver, 1987):

𝑁𝑂2 ℎ𝑣 𝑁𝑂 + 𝑂. (4.1)

𝑂. + 𝑂2 → 𝑂3 (4.2)

𝑂3 + 𝑁𝑂 → 𝑁𝑂2 + 𝑂2 (4.3)

As illustrated by Equations 4.1, 4.2, and 4.3, a steady state, constant level of O3 production will

be reached if there are no other chemicals to compete for oxygen free radicals. The dissociation

of the O3 requires higher energy (UV portion) of the visible electromagnetic spectrum than NO2.

Hence, “the naturally occurring ozone in the stratosphere is beneficial as it shields the earth

from harmful ultraviolet radiation, while ozone at ground level is a major environmental and

health concern” (MOE, 2010).

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PM2.5 includes smoke, fumes, dust and pollen that are 2.5 microns in diameter or less. In

Ontario, the main occurrences for both O3 and PM2.5 are in transportation corridors. Exposure to

high levels of O3 and PM2.5 can cause leading health problems such as chest tightness, coughing

and has been linked to increased hospital admissions and premature death (MOE, 2010).

Generally, the process of ground level ozone formation and changes in concentrations of O3 and

NOx are very complex. When there is significant concentration of low molecular weight

particulates from automobile exhaust (PM2.5), they replace O3 in Equation 4.3 and react with NO

to produce NO2. This decreases the rate of O3 removal by NO, which increases the O3

concentration. Meteorological conditions that reduce the atmospheric rate of dispersion and

dilution of air pollutants are also responsible for changes in concentration of O3 (Piver 1987).

For example, during early hours of morning, there is a nocturnal temperature inversion effect;

lower rate of emission removal by air motion than the rate of entry to the air from exhaust

emissions. As a result, there exists a stable atmosphere with high concentration of nitric oxide,

and nitrogen dioxide. Ozone concentration is more or less at a steady state due to high

concentrations of NO2 and NO. During midday, due to the increase in temperature of earth’s

surface related to that of the air above the earth’s surface, the atmosphere becomes more

unstable. This increases the vertical air movement and mixing of air pollutants, hence PM2.5

replaces O3 in Equation 4.3. As a result the concentration of O3 increases, while the

concentration of NO2 and NO decrease. In Ontario, elevated concentrations of ozone are

generally observed during noon to early evening on hot sunny days from May to September

(MOE, 2010).

3.3 Air Quality in Ontario Cities

The provincial real-time air quality monitoring system has been operated by the Ontario

Ministry of Environment since 1988. Across Ontario, the Ministry has a network of 40 ambient

air quality monitoring stations. The air quality index (AQI) ranges of values correspond to very

poor to very good air quality, as shown in Table 3.1.

The calculation for AQI is not straightforward and is not covered in this project, but briefly, it is

in part based on limiting values for emissions in Ontario as shown in Table 3.2. Further

information on the computation of the AQI can be retrieved from (MOE, 2012).

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Table 3.3 presents a summary of Ontario regions with the highest number of smog advisories

issued and the highest number of advisory days based on the Ministry of the Environment

Ontario (MOE, 2012). The region of Windsor-Essex-Chatham-Kent has the highest number of

smog advisories and the highest number of advisory days and so it is examined further in this

study. The City of Toronto had the second most number of smog advisories issued and the

seventh highest number of advisory days. The City of Toronto is also further examined largely

because of the current field application of photocatalytic highway noise barriers located on the

south side of Highway 401 between the Don Valley Parkway and Victoria Park Avenue.

Table 3.1: Air quality index range (MOE, 2012)

AQI Reading Interpretation

0-15 Very Good

16-31 Good

32-49 Moderate

50-99 Poor

100 plus Very Poor

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Table 3.2: Limiting values for emissions in Ontario (MOE, 2012)

Pollutant Unit AAQC* Averaging time

O3 ppb 80 1 hr

NOx ppb

100 24 hr

200 1 hr

SO2 ppb

20 Annual

100 24 hr

250 1 hr

CO

ppm

13 8 hr

30 1 hr

PM2.5 µg/m3

30 24 hr

TRS µg/m3 14 24 hr

* AAQC : Ambiant Air Quality Criteria (AAQCs)

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Table 3.3: Regions in Ontario with the highest smog advisories

Air Quality Forecast

Region

No. of

advisories

issued

(2003–2010)

Rank

based on no.

of advisories

issued

No. of

advisory

days

(2003–2010)

Rank

based on

no. of

advisory

days

Windsor-Essex-

Chatham-Kent 52

1

(highest)

158

1

(highest)

Halton-Peel 51 2 142 4

City of Toronto 51 2 139 7

City of Hamilton 50 3 142 4

Elgin 50 3 155 2

York-Durham 50 3 135 9

(lowest)

Simcoe-Delhi-Norfolk 49 4 143 3

Dunnville-Caledonia-

Haldimand 49 4

140 6

Oxford-Brant 49 4 141 5

Sarnia-Lambton 49 4 141 5

London-Middlesex 48 5

(lowest) 138 8

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3.4 Pollution Fluctuations

3.4.1 Hourly Trend

The locations of the Windsor DT and four Toronto air quality monitoring stations are indicated

in Table 3.4. This study only examines the hourly fluctuations of two selected locations:

Windsor DT and Toronto E stations. The Toronto E station was chosen because it is the closest

station to the field trial of the photocatalytic noise barrier. Figures 3.1 and 3.2 show the hourly

data of O3 and NOx concentrations at the Windsor DT station for May to September,

respectively and Figures 3.3 and 3.4 show similar trends for the relatively cooler months,

namely, October to April. The data in the plot is an average of the data available from 2000-

2011. The data shows that there are large changes in O3 and NOx concentrations throughout the

day for relatively warm temperature months (i.e., May to September). Appendix A shows the

corresponding plots, for Toronto E station, and they follow the same trends observed for the

Windsor DT station.

Table 3.4: Station locations

Air Quality Forecast

Region Station Name Location of the Station

Windsor-Essex-

Chatham-Kent Windsor DT 467 University Ave. W.

City of Toronto

Toronto DT Bay St./Wellesley St. W.

Toronto W 125 Resources Rd.

Toronto E Kennedy Rd./Lawrence Ave. E.

Toronto N Hendon Ave./Yonge St.

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Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

O3 (

pp

b)

0

10

20

30

40

50

60May

Jun

Jul

Aug

Sep

Figure 3.1: Windsor DT O3 hourly data from May to Sept (2000-2011)

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

NO

x (

pp

b)

0

10

20

30

40

50

60May

Jun

Jul

Aug

Sep

Figure 3.2: Windsor DT NOx hourly data from May to Sept (2000-2011)

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Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H1

0

H1

1

H1

2

H1

3

H1

4

H1

5

H1

6

H1

7

H1

8

H1

9

H2

0

H2

1

H2

2

H2

3

H2

4

O3 (

pp

b)

0

10

20

30

40

50

60

Oct

Nov

Dec

Jan

Feb

Mar

Apr

Figure 3.3: Windsor DT O3 hourly data from Oct to April (2000-2011)

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H1

0

H1

1

H1

2

H1

3

H1

4

H1

5

H1

6

H1

7

H1

8

H1

9

H2

0

H2

1

H2

2

H2

3

H2

4

NO

x (

pp

b)

10

20

30

40

50

60

Oct

Nov

Dec

Jan

Feb

Mar

Apr

Figure 3.4: Windsor DT NOx hourly data from Oct to April (2000-2011)

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3.4.2 Monthly Trend

The average monthly data of all the pollutant concentrations of the regions in Ontario with

highest smog advisories were examined. Figure 3.5 shows the monthly data of O3 concentration

for all of the stations. The data in the plot is an average of the data available from 2000-2011.

Based on the data in Figure 3.5, regions with the highest O3 concentrations were selected for

further investigation of their other pollutants concentrations. Figure 3.6 shows the monthly data

of NOx for those regions. Although none of Toronto’s stations were within the top 5 stations

with high O3 concentration.

As shown in Figures 3.5 and 3.6, the average monthly O3 and NOx concentration fluctuation is

consistent with the hourly data and it follows the same trend as the hourly data; with an increase

in temperature, there is an increase in O3 concentration and a decrease in the concentration of

NOx.

This data reveals that the hourly and monthly changes in pollution concentrations are an

important factor to account for when monitoring air quality. The pollution-abating effectiveness

of photocatalytic concrete field applications may be over-estimated or underestimated if hourly

or monthly changes in pollution concentration levels are not accounted for in the air pollution

monitoring program.

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Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

O3 (

pp

b)

0

10

20

30

40

50

60

Windsor DT

Windsor W

Oakville

Toronto DT

Toronto W

Toronto E

Toronto N

Hamilton DT

Hamilton MT

Hamilton W

Port Stanley

Oshawa

Brantford

Sarnia

London

Figure 3.5: O3 monthly data for regions in Ontario with the highest smog advisories (2000-

2011)

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Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

x (

ppb)

0

10

20

30

40

50

60

Windsor DT

Hamilton MT

Oshawa

Brantford

Sarnia

Toronto DT

Toronto W

Toronto E

Toronto N

Figure 3.6: NOx monthly data for regions in Ontario with the highest smog advisories

(2000-2011)

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3.5 Estimated Removal Efficiency

To estimate the potential NO removal efficiency of the photocatalytic concrete, a total of eight

stations are considered. Four stations, Windsor DT, Hamilton MT, Sarnia, and Oshawa, were

selected based on their high O3 concentration level and geographic location in Ontario. In

addition four Toronto stations were also considered, namely, Toronto DT, W, E and N.

Appendix B presents the average monthly pollution concentrations from 2000-2011 for NOx,

NO2, and NO of the above mentioned stations.

Using the average month wind speed data reported by Windfinder (2012), the NO

concentrations in mg/h/m2 were calculated based on Equation 4.4 and shown in Figures 3.7 and

3.8:

𝐴 =(𝑏×𝑐×273.15×𝑑)

22.4136×(273.5+𝑒)×760 (4.4)

where 𝐴 is the concentration of NO (mg/h/m2), 𝑏 is the concentration of NO (ppm), 𝑐 is the

molecular weight of NO, 𝑑 is the atmospheric pressure (mmHg), and 𝑒 is the ambient air

temperature (˚C).

In addition, Figures 3.7 and 3.8 show two horizontal lines that represent two abatement levels, a

relatively low NO degradation rate and a relatively high NO degradation rate, which are 6 and

20 mg/h/m2, respectively. The basis for these abatement rates is detailed in Churchill and

Panesar (2012). Table 3.5 presents the maximum and minimum NO concentration for each

monitoring station. The month in which the maximum and minimum are observed are also

reported. In general, it is observed that the maximum available NO is most commonly found in

February, whereas the minimum NO concentrations for all stations except Sarnia occurs in July.

The percentage removal efficiency is calculated based on the low and high abatement rates of 6

and 20 mg/h/m2, respectively. Considering a 6 mg/h/m

2 abatement rate, up to 20% NO

abatement can be achieved, and if an abatement rate of 20 mg/h/m2

occurs, up to 67% NO

abatement is estimated at the Hamilton MT location. In Toronto, a range of 3% to 24% removal

efficiency is calculated. In general, these estimates fall within the pollution abatement

effectiveness reported in the literature.

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Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

(m

g/h

/m2)

0

200

400

600

NOx Abatement Rate: 6 mg/h/m2

NOx Abatement Rate: 20 mg/h/m2

Windsor DT

Hamilton MT

Oshawa

Sarnia

Figure 3.7: Average monthly NO concentration (mg/h/m2) (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

(m

g/h

/m2)

0

200

400

600

NOx Abatement Rate: 20 mg/h/m2

NOx Abatement Rate: 6 mg/h/m

2

Toronto DT

Toronto W

Toronto E

Toronto N

Figure 3.8: Average monthly NO concentration for Toronto (mg/h/m2) (2000-2011)

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Table 3.5: Percentage removal efficiency (%)

Removal Efficiency (%)

Station

Name

Available NO Abatement Rate

Month (mg/h/m2)

6.00

(mg/h/m2)

20.00

(mg/h/m2)

Windsor

DT

Max Dec 363.35 1.65 5.50 Min

Min Jul 58.08 10.33 34.44 Max

Hamilton

MT

Max Nov 173.70 3.45 11.51 Min

Min Jul 30.07 19.95 66.51 Max

Sarnia

Max Feb 173.86 3.45 11.50 Min

Min Aug 54.77 10.96 36.52 Max

Oshawa

Max Feb 222.34 2.70 9.00 Min

Min Jul 56.19 10.68 35.59 Max

Toronto

DT

Max Feb 295.82 2.03 6.76 Min

Min Jul 83.63 7.17 23.91 Max

Toronto W

Max Feb 684.68 0.88 2.92 Min

Min Jul 227.75 2.63 8.78 Max

Toronto E

Max Feb 546.44 1.10 3.66 Min

Min Jul 146.70 4.09 13.63 Max

Toronto N

Max Feb 409.62 1.46 4.88 Min

Min Jul 93.22 6.44 21.45 Max

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Chapter 4 Experimental Program

4.1 Introduction

The objective of the experimental part of the research is to compare conventional concrete made

using GU cement to concrete containing photocatalytic cement in context with mechanical,

transport and durability properties. The experimental program has been divided into four phases:

Phase I: Investigating cement paste

Phase II: Investigating concrete

Phase III: Investigating concrete with finished and formed surfaces, with minimum

variance in the amount of air content

Phase IV: Investigating concrete with finished and formed surfaces, with minimum

variance in both air content and slump

4.2 Materials

Throughout the experimental work the following materials were used:

4.2.1 Cementing Materials

Ordinary portland cement (OPC), obtained from Holcim Cement, Mississauga, Canada; Saylor’s

portland cement type I/II (GU) and photocatalytic TX Active Aria GB cement (PH), both of

which were obtained from Essroc Cement Corporation shipped from Front Royal Cement; and

Grade 100 GGBFS was obtained from Holcim Cement Canada. The chemical composition for

each of the cementing materials used in the experiments is shown in Table 4.1.

Recognizing that photocatalytic cement is not typically used in combination with supplementary

cementing materials because it will dilute the pollution abating effectiveness, GGBFS is blended

with OPC, GU and PH to assess if the expected behaviour will occur in the presence of TiO2.

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Table 4.1: Chemical composition of cementing materials

Main

Constituent

OPC

(%)

GU

(%)

PH

(%)

GGBFS

(%)

SiO2 17.15 19.1 16.83 34.07

Al2O3 4.04 3.69 3.12 7.33

Fe2O3 2.19 3.06 2.72 0.45

CaO 57.43 61.3 55.12 35.77

MgO 3.03 2.67 3.23 14.16

SO3 5.75 6.37 4.27 1.24

K2O 1.27 1.12 0.89 0.55

Na2O 0.32 0.23 0.34 0.45

TiO2 0.24 0.2 5.71 0.53

The density of the materials was measured using a stereo pyncometer. The device employs

Archimede’s principle of fluid displacement to determine the volume of solid objects. The

displaced fluid is helium gas that penetrates the finest pores. The equation to calculate is

(Quantachrome Instruments, 2007):

𝑉𝑃 = 𝑉𝐶 +𝑉𝐴

1− 𝑃2

𝑃3

(4.1)

𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 𝑆𝑎𝑚𝑝𝑙𝑒 𝑀𝑎𝑠𝑠 (𝑔)

𝑉𝑃 (4.2)

where 𝑉𝑃 is volume of powder (cm3), 𝑉𝐶 is the volume of sample cell holder (cm

3), 𝑉𝐴is the

added volume, 𝑃2 pressure reading after pressurizing cell (psi), and 𝑃3is pressure reading (psi)

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after adding 𝑉𝐴. This test was run 3 times per sample and the average density of each material is

shown in Table 4.2.

Table 4.2: Density of powder materials

Material Source Density (g.cm-3

)

OPC Holcim 3.11

GU Essroc 3.14

PH Essroc 3.18

GGBFS Holcim 2.95

4.2.2 Aggregate

4.2.2.1 Coarse Aggregate

The coarse aggregate used was a crushed limestone with a maximum size of 13 mm and was

supplied by Dufferin Aggregates Milton Quarry. The specific gravity and absorption of the

coarse aggregate were 2.89 and 1.97%, respectively.

4.2.2.2 Fine Aggregate

The fine aggregate used was natural sand from the CBM Sunderland Pit. The specific gravity,

fineness modulus and absorption of the sand were experimentally determined to be 2.72, 2.50

and 0.63%, respectively.

4.2.3 Chemical Admixtures

The air-entraining admixture (AEA) used in phases I, II, and III of the experimental program

was Airextra, obtained from Euclid Concrete Admix, with a specific gravity of 1.07. In phase

IV, MicroAir with a specific gravity of 1.01 was used as the AEA. Glenium 7700, a

polycarboxylate-based high range water reducing admixture with a specific gravity of 1.064,

was used as the superplasticizer (HRWR). Both MicroAir and HWR were provided by BASF

Canada.

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4.3 Phase I

4.3.1 Introduction

The objective of this phase of the research involves investigation and comparison of

conventional cement pastes made using OPC and GU to cement paste containing PH in context

with strength and porosity. The preliminary selection of cement paste mix design variables are

based on the findings reported in the literature. The effects of water to cement ratio (w/c), the

presence of GGBFS, and the curing age have also been examined. Furthermore, the difference

between OPC and GU in comparison to PH was also investigated.

4.3.2 Mix Design

Ten mix designs were prepared for the experimental program as summarized in Table 4.3.

4.3.3 Mixing, Casting and Curing

The ASTM C305-06 mixing procedure was used. The dry paddle and dry bowl were placed in

the mixing position in the mixer. The measured amount of the materials was introduced into the

bowl in the following manner: hand-mix the dry cementing material for 30s; place the water in

the mixing bowl; add the mixed cementing material to the water and allow 30s for the

absorption of the water; start the mixer at the slow speed (140 ± 5r/min) for 30s; stop the mixer

for 15s and scraped down the paste on sides of the bowl into the batch; start the mixer at

medium speed (285 ± 10r/min) and mix for 60s.

For each mixture, six cubes were cast into molds of 50mm × 50mm × 50 mm and compacted in

two layers using a plastic compacting bar, where each layer was compacted 25 times. Then the

molds were immediately covered with plastic to avoid moisture loss, and were kept at room

temperature (23 ± 2°C) for 24 hours. Then the specimens were demolded and cured in a lime-

saturated water container at room temperature prior to test days.

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Table 4.3: Mix design proportions (Phase I)

Mix # Mix ID

OPC

(%)

GU

(%)

PH

(%)

GGBFS

(%)

w/c ratio

1 OPC0.42-I 100 0 0 0 0.42

2 GU0.42-I 0 100 0 0 0.42

3 OPC0.5-I 100 0 0 0 0.5

4 OPC25S0.42-I 75 0 0 25 0.42

5 GU25S0.42-I 0 75 0 25 0.42

6 OPC25S0.5-I 75 0 0 25 0.5

7 PH0.42-I 0 0 100 0 0.42

8 PH0.5-I 0 0 100 0 0.5

9 PH25S0.42-I 0 0 75 25 0.42

10 PH25S0.5-I 0 0 75 25 0.5

4.3.4 Testing Procedure

4.3.4.1 Cube Strength

The cube strength of the cement paste was determined based on ASTM C109 after 3 and 28

days. Prior to the test, samples were removed from the curing environment, surface dried by

towel, and weighed.

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4.3.4.2 Mercury Intrusion Porosimetry (MIP)

The Quantachrome Autoscan Porosimeter device was used to determine the total porosity of all

the paste mix designs. MIP measures porosity by entering mercury into the (dried) capillary

pore system of materials under pressure. The Washburn equation is used:

𝑃 =−4𝛾 𝑐𝑜𝑠𝜃

𝑑 (4.3)

where 𝑃 is pressure, 𝛾 is the surface tension of the liquid, 𝜃 is the contact angle of the liquid,

and 𝑑 is the capillary diameter (Abell et al., 1999). The total porosity was evaluated by using the

MIP device. After the compressive strength test, the paste specimens were crushed and left to

soak in liquid nitrogen for 5 to 10 minutes to terminate the hydration process. The specimens

were then placed in the vacuum freezer at -20±2 °C for 24 hours followed by vacuum oven at

40±2°C for another 24 hours, while surrounded by silica gel and soda lime to minimize the

occurrence of carbonation. Prior to the MIP test, the samples were ground by mortar and pestle

into small pieces to pass 5mm sieve and remain on 2.5mm sieve.

4.4 Phase II

4.4.1 Introduction

The objective of this phase of the research involves a comparison of conventional concrete made

using GU cement to concrete containing PH cement in context with mechanical and transport

properties. The preliminary selection of concrete mix design variables are based on the findings

reported in the literature and phase I of this report.

It should be noted that PH cement, produced by Essroc, is simply the GU cement, from Essroc

with the addition of proprietary particles of TiO2. OPC was eliminated from the mix design to

minimize the variables due to different cement suppliers.

The properties of photocatalytic concrete samples were compared with conventional concrete at

w/c of 0.42. The effects of the presence of 25% ground granulated blast furnace GGBFS as well

as the curing age were also examined.

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4.4.2 Mix Design

All mixes had a total cementing material design mass of 428.6 kg/m3 and a w/c ratio of 0.42.

The coarse aggregate content for all mixes was 900 kg/m3. Table 4.4 presents the concrete mix

design proportions.

Table 4.4: Mix design proportions (Phase II)

Mix

# Mix ID

Cementing Material Aggregate

Water AEA

GU PH GGBFS Coarse Sand

Units kg/m3 mL/100kgcement

1 GU-II 428.6 0 0 900 875 180 52

2 GU25S-II 321.4 0 107.1 900 867 180 52

3 PH-II 0 428.6 0 900 876 180 52

4 PH25S-II 0 321.4 107.1 900 869 180 52

4.4.3 Mixing, Casting and Curing

The ASTM C192-07 mixing procedure was used. All mixtures were prepared in 40 L batches in

a 65 L capacity pan mixer. First all the dry ingredients were added at once and mixed for 1 min;

the AEA was diluted in the mixing water; the mixing water was added and mixed for 3 min;

stop the mixer for 3 min and allow the mix to rest; start the mixer and mix for another 2 min.

For each mixture, sixteen cylinders (100mm x 200mm) were cast and compacted in three layers,

where each layer was compacted 25 times. Then the cylinders were immediately covered with

plastic lid to avoid moisture loss, and were kept at curing room at 23±2°C and 100% RH for 24

hours. The samples were then demolded and kept in the same curing room until testing.

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4.4.4 Testing Procedure

4.4.4.1 Fresh Concrete Properties

The following tests, listed in Table 4.5, were evaluated for each of the four mix designs.

Table 4.5: Fresh concrete property tests

Type of test Standard Units

Slump CSA A23.2-5C mm

Air Content ASTM C231 %

Density CSA A23.2-6C kg/m3

4.4.4.2 Mechanical Properties

Mechanical properties of the four mix designs were evaluated after 28 and 56 days of curing.

All of the tests are listed in Table 4.6.

4.4.4.2.1 Compressive Strength

Compressive strength of the concrete cylinders was determined based on CSA A23.2-9C. Three

cylinders per mix design and curing age were tested. Prior to the test, samples were removed

from the curing environment, both ends of the cylinders were ground (5 to 10 mm), surface

dried by towel, weighted, and the dimensions were measured.

4.4.4.2.2 Hardened Density

Density of the concrete specimens was determined based on CSA A23.2-11C. Two cylinders

per mix design and curing age were tested. Prior to the test, cylinders were removed from the

curing environment, cut into half the length, weighted, and the dimensions were measured.

4.4.4.2.3 Ultrasonic Pulse Velocity (UPV)

Ultrasonic pulse velocity (UPV) of the concrete specimens was determined based on ASTM

C597, to help in assessing the uniformity and relative changes in the quality of concrete in

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different mixes. Three cylinders per mix design and curing age were tested. Prior to the test,

samples were removed from the curing environment, both ends of the cylinders were ground (5

to 10mm), surface dried by towel, weighted, and the dimensions were measured.

4.4.4.2.4 Hardened Air Content

Air content of the hardened concrete samples were measured based on ASTM C547. One

cylinder per mix design and curing age was tested. Prior to the test, the cylinder was removed

from the curing environment, cut into half lengthwise, and each half was cut into two sections

with a height of about 80mm.

Table 4.6: Mechanical property tests

Type of test Standard Units

Compressive Strength CSA A23.2-9C MPa

Hardened Density CSA A23.2-11C kg/m3

UPV ASTM C597 m/s

Hardened Air Content ASTM C457 %

4.4.4.3 Transport Properties

The transport properties of the four mix designs were evaluated after 28 and 56 days of curing.

4.4.4.3.1 Rapid Chloride Permeability

A rapid chloride permeability test (RCPT) was performed based on ASTM C1202 to determine

the resistance to chloride ion penetration. Two cylinders per mix design and curing age were

tested. Prior to the test, the cylinders were removed from the curing environment, cut into two

sections of 50mm thick, and the dimensions were measured.

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4.5 Phase III

4.5.1 Introduction

The objective of this phase of research involves a comparison of mechanical, transport and

durability properties the conventional concrete made using GU cement to concrete containing

PH, both with finished and formed surfaces. The properties of the photocatalytic concrete

samples have been investigated by comparing them with conventional concrete at w/c of 0.42.

The effects of the presence of GGBFS as well as the curing age were also examined.

4.5.1.1 Foam Index Test

Prior to the phase III mix design, due to the low plastic air content of the photocatalytic concrete

in phase II and the difficulty in entraining air in PH concrete, the foam index test was conducted

to help determine the proper amount of required air-entraining admixture (AEA) sufficient to

produce a stable air-void system in the photocatalytic concrete.

For this test, the aqueous solutions of the air entraining admixture were prepared in 2%, 6%,

10%, and 15% strengths of air entraining admixture by volume. The mixture of 20 grams

cement and 50 ml distilled water was mixed for 60s followed by the addition of diluted air-

entraining solution in the intervals. The mixture was shaken for 45s. If the foam on the surface

is not stable and in the continuous layer, further air-entraining solution should be added until a

stable and continuous foam is achieved. The minimum amount of air‐entraining admixture

needed to produce stable foam was established as the foam index (Lashley, 2009). Average

foam index values were calculated based on the following steps:

(1) massAEA = massAEAsol/ 5* = massAEA

(2) massAEA / kgcem [gAEA/ kgcem] = massAEA/20 [g cem] x 1000 [gcem /kgcem]

(3) densityAEA = density[gAEA/mL]

(4) foam index [mLAEA/ kg cem] = massAEA/kgcem / densityAEA

*Using a 1:4 dilute AEA solution

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Table 4.7: Paste mix proportions used for the foam index test methods

GU

(g)

PH

(g)

Distilled Water

(g)

Foam Index

(ml AEA/kgcem)

Mix #1 20 0 50 1.25

Mix #2 0 20 50 0.47

Figure 4.1: Mix#1 and Mix#2 before addition of AEA solution (left), foam on the surface after

addition of AEA and shaking for 45s (right)

As illustrated in Figure 4., the surface of the mixture of PH and water (mix#2) is not as clear as

mix#1 and already started the formation of the foam on the surface. In addition, results from the

fresh air content test of the trial batches were not consistent with the results from the foam index

test. Based on the fresh air content test (ASTM C231), in order to reach 5% air content for

concrete with GU and PH cement, the required AEA (ml/kgcem) is 0.75 and 5.25 respectively.

It can be concluded that due to the surface appearance of the mix#2, the foam index test is not a

good indicator of required AEA for mixes with PH cement.

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4.5.2 Mix Design

All mixes had a total cementing material design mass of 429 kg/m3 and a w/c of 0.42. The

coarse aggregate content for all mixes was 892 kg/m3. Table 4.9 presents the concrete mix

design proportions.

Table 4.8: Mix design proportions (Phase III)

Mix

# Mix ID

Cementing Material Aggregate

Water AEA

GU PH GGBFS Coarse Sand

Units kg/m3 mL/100kgcement

1 GU-III 429 0 0 892 883 180 74

2 GU25S-III 321 0 107 892 875 180 78

3 PH-III 0 429 0 892 884 180 530

4 PH25S-III 0 321 107 892 877 180 530

4.5.3 Mixing, Casting and Curing

The ASTM C192-07 mixing procedure was used. All mixtures were prepared in 60 L batches in

a 65 L capacity pan mixer. First, all the dry ingredients were added at once and mixed for 1 min;

the AEA was diluted in the mixing water; the mixing water was added and mixed for 3 min;

mixing was stopped for 3 min, and then the mixture was mixed for another 2 min.

For each mixture, eighteen cylinders (100mm x 200mm), four slabs (300mm x 200mm x

75mm), and two prisms (75mm x 75mm x 300mm) were cast and compacted in three layers,

with each layer compacted 25 times. The cylinders were then immediately covered with plastic

lids to avoid moisture loss, and were kept in a curing room at 23±2°C and 100% relative

humidity for 24 hours. The samples were then demolded and kept in the same curing room until

testing. Slabs were immediately covered with plastic and kept at room temperature for the first

24 hours. Then they were demolded and kept in a curing room at 23±2°C and 100% relative

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humidity for 14 days, followed by dry curing in a room at 23±2°C and 50% relative humidity

for another 14 days. As for the prisms, they were immediately covered with plastic and kept at

room temperature for the first 24 hours. They were then demolded and kept in a curing room at

23±2°C and 100% relative humidity for 28 days.

4.5.4 Testing Procedure

4.5.4.1 Fresh Concrete Properties

The testing procedures for fresh properties were the same as in Phase II.

4.5.4.2 Mechanical Properties

The testing procedures for mechanical properties were the same as in Phase II.

4.5.4.3 Transport Properties

All of the tests are listed in Table 4.9. The testing procedure for RCPT was the same as in Phase

II.

Table 4.9: Transport property tests

4.5.4.3.1 Sorptivity

Sorptivity testing was performed based on ASTM C1585 to determine the sorption coefficient

(mm/sec1/2

). Three cylinders per mix design and curing age were tested. As soon as the samples

reached the targeted curing age of 28 and 56 day at 100% relative humidity, they were removed

from the curing environment, weighed, and the dimensions were measured. The specimens were

then conditioned at 50°C and 80% relative humidity for three days, followed by 15 days in a

sealed container at room temperature. To evaluate the effect of surface on sorptivity, both top

(finished) and bottom (formed) surfaces of a standard cylinder were tested.

Type of test Standard Units

RCPT ASTM C1202 Coulombs

Sorptivity ASTM C1585 mm/sec1/2

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4.5.4.4 Durability Properties

All the durability tests performed are listed in Table 4.10. Slabs and prisms were used for

scaling resistance and rapid freezing and thawing tests, respectively.

Table 4.10: Durability property tests

4.5.4.4.1 Resistance to Salt Scaling

Salt scaling testing was performed using on MTO LS-412 to determine the resistance to scaling

of a horizontal concrete surface exposed to freeze/thaw cycles in the presence of a 3% NaCl de-

icing solution. Two slabs per mix design were tested. Prior to the test, samples were removed

from the curing environment and prepared based on the standard.

The specimens were subjected to 50 freeze/thaw cycles, with one cycle lasting 24 hours. The

samples were kept in freezing condition for 16 to 18 hours at –18±2ºC and then in thawing

condition for 6 to 8 hours at 23±2ºC and 50±5% relative humidity. The dry mass of the flaked

off material from the surface of the concrete slabs, was measured every five cycles. A salt

scaling value of 0.8 kg/m2 is the specified acceptance limit in accordance with OPSS 1351.

4.5.4.4.2 Resistance to Rapid Freezing and Thawing Damage

Freeze/thaw resistance was performed using on ASTM C666 Procedure A to determine the

relative dynamic modulus and durability factor of the specimens as an indicator of internal

micro-cracking in the concrete. Two prisms per mix design were tested. The relative dynamic

modulus, Pc , and the durability factor, DF, were calculated using Equations 4.4 and 4.5.

Type of test Standard Units

Resistance to Salt Scaling MTO LS-412 Kg/m2

Resistance to Rapid Freezing and Thawing ASTM C666 %

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49

𝑃𝑐 = 𝑛1

2

𝑛2 × 100 (4.4)

𝐷𝐹 =𝑃𝑁

300 (4.5)

where n1 is the fundamental transverse frequency after c freeze/thaw cycles, n is the

fundamental transverse frequency prior to cycling, and N is the number of cycles at which

testing was terminated. The specimens were measured at the intervals of 36 to 40 cycles for both

the length change and fundamental transverse frequency.

4.6 Phase IV

4.6.1 Introduction

Due to poor scaling results for PH concrete in Phase III, which is explained in chapter 5, a new

set of mix designs were tested in Phase IV to trigger the primary difference in slump. The

objective of this phase of research involved an examination of the effects of the addition of a

polycarboxylate-based high range water reducing admixture in comparison to conventional

concrete made using GU cement to concrete containing photocatalytic, both with finished and

formed surfaces, on the following properties:

Mechanical properties: Compressive Strength, UPV, and Hardened Air content;

Transport properties: RCPT and Sorptivity;

Durability properties: Resistance to Salt Scaling.

The properties of the photocatalytic concrete samples have been investigated by comparing

them with conventional concrete at w/c of 0.42.

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4.6.2 Mix Design

Table 4.11: Mix design proportions (Phase IV)

Mix # Mix ID

Cementing

Material Aggregate

Water AEA HRWR

GU PH Coarse Sand

Units kg/m3 mL/100kgcement

1 GU-IV 429 0 892 883 180 5.7 116

3 PH-IV 0 429 892 884 180 29 300

4.6.3 Mixing, Casting and Curing

The ASTM C192-07 mixing procedure was used. All mixtures were prepared in 60 L batches in

a 65 L capacity pan mixer. First, all the dry ingredients were added at once and mixed for 1 min;

the AEA was diluted in the mixing water; the mixing water was added, then the HRWR was

added and mixed for 3 min; mixing was stopped for 3 min, and then the mixture was mixed for

another 2 min.

For each mixture, nine cylinders (100mm x 200mm) and four slabs (300mm x 200mm x 75mm)

were cast and compacted in three layers, with each layer compacted 25 times. The cylinders

were then immediately covered with plastic lids to avoid moisture loss, and were kept in a

curing room at 23±2°C and 100% relative humidity for 24 hours. The cylinders were then

demolded and kept in the same curing room for 28 days. Slabs were immediately covered with

plastic after the casting and kept at room temperature for the first 24 hours. Then they were

demolded and kept in a curing room at 23±2°C and 100% relative humidity for 14 days,

followed by dry curing in a room at 23±2°C and 50% relative humidity for another 14 days.

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Chapter 5 Results and Discussion

5.1 Phase I

The compressive strength and the total porosity of all the specimens at 3 and 28 days of curing

are shown in Table 5.1. It should be noted that the results for compressive strength and total

porosity are the average of 3 measurements. However, for mix PH25S0.42-I the strength at age

of 3 days is the average of two measurements due to one outlier.

5.1.1 Compressive Strength

As shown in Figure 5., all the samples demonstrated a consistent trend of increase in strength

with further curing regardless of their mix design proportions. The error bar is ± one standard

deviation. Both OPC and GU demonstrate similar cube strength at w/c of 0.42 which shows the

different source of cement does not have a significant effect on the strength. However, addition

of 25% slag reduces the strength in GU sample.

For all the samples, the strength is decreasing with the increase in water to cement ratio (from

0.42 to 0.5). This trend stays the same with the addition of 25% GGBFS. At early ages, it is

expected that the presence of GGBFS reduces the cube strength, owing to its latent hydraulic

and pozzolanic properties. However, addition of the 25% GGBFS as a substitute for OPC and

PH, at lower w/c ratio and longer curing age, enhances the strength about 2% to 3%. It should

be noted that for all mixtures, the coefficient of variation for all strength measurements was less

than 10.5 %.

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52

Table 5.1: Strength and porosity assessments (Phase I)

MIX ID

Curing

Age (Day)

Compressive Strength Total

Porosity

(%)

Average

(MPa)

Standard

Deviation

Coefficient of

Variation (%)

OPC0.42-I 3 45.3 1.5 3.3 27.1

28 67.1 2.8 4.1 18.1

GU0.42-I 3 46.8 3.4 7.3 24.4

28 75.7 1.4 1.8 20

OPC0.5-I 3 31.8 0.8 2.7 31.9

28 50 2.5 5.1 25.2

OPC25S0.42-I 3 40.2 1.9 4.7 23.6

28 68.4 4.8 7.1 17.5

GU25S0.42-I 3 25.9 1.3 5.1 24.6

28 55.7 1.7 3.1 22.4

OPC25S0.5-I 3 26.3 2.7 10.2 33.4

28 46.7 2.5 5.3 25

PH0.42-I 3 40.1 1.3 3.3 34.8

28 60.1 1.3 2.2 18.7

PH0.5-I 3 20 0.2 1 43.1

28 32 0.9 2.8 36

PH25S0.42-I 3 37.2 0.8 2.3 29.3

28 62 1.8 3 26.3

PH25S0.5-I 3 8.3 0.2 2.8 50

28 23.5 0.5 2 44.6

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53

Mix ID

OP

C0

.42

-I

G-I

U0

.42

OP

C0

.5-I

OP

C2

5S

0.4

2-I

GU

25

S0

.42

-I

OP

C2

5S

0.5

-I

PH

0.4

2-I

PH

0.5

-I

PH

25

S0

.42

-I

PH

25

S0

.5-I

Cu

be

Str

eng

th (

MP

a)

0

20

40

60

80

100

3d

28d

Figure 5.1: Strength of Samples (Phase I)

Note: Each bar represents the average of three measurements except for PH25S0.42-I at 3d (two

measurements)

5.1.2 Porosity

Figure 5. shows the relationship between the total porosity of the samples with respect to their

mix design and curing age base on MIP analysis. Regardless of the mix design proportions, the

porosity of the samples decreases with longer curing. At early age and lower w/c, the porosity of

PH cement paste is approximately 28% and 42% higher than that of OPC cement paste and GU

cement paste, respectively. However, after 28 day of curing, this difference at low w/c reduces

to near 3% with OPC cement paste. At 28 day, the porosity of the PH sample is 7% lower than

that of GU.

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54

Furthermore, at w/c of 0.42, the addition of 25% GGBFS increases the early age porosity of PH

cement paste for up to 24% and 16% in comparison to OPC and GU, respectively. For the OPC

and PH samples at w/c of 0.5, the addition of 25% GGBFS does not have a significant effect on

the total intruded porosity when compared to the samples without GGBFS.

Mix ID

OP

C0.4

2-I

GU

0.4

2-I

OP

C0.5

-I

OP

C25S

0.4

2-I

GU

25S

0.4

2-I

OP

C25S

0.5

-I

PH

0.4

2-I

PH

0.5

-I

PH

25S

0.4

2-I

PH

25S

0.5

-I

Po

rosi

ty (

%)

0

10

20

30

40

50

60

3d

28d

Figure 5.2: Porosity of samples (Phase I)

Note: Each bar represents one measurement

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55

5.1.3 Effects of Paste Mix Design Variables – Phase I

Porosity (%)

20 30 40 50

Cu

be

Str

eng

th (

MP

a)

0

10

20

30

40

50

60

70

80

GU0.42-I

GU25S0.42-I

OPC0.42-I

OPC0.5-I

OPC25S0.42-I

OPC25S0.5-I

PH0.42-I

PH0.5-I

PH25S0.42-I

PH25S0.5-I

3d

28d

R2= 0.6908

R2= 0.8397

Figure 5.3: Porosity vs. Strength

As mentioned previously, the variables for Phase I were w/c ratio, curing age and the addition of

GGBFS. Figure 5. shows the relationship between porosity and strength at different curing age

of the samples. Regardless of the type of cement, samples with lower water cement ratio of 0.42

improved both strength and pore structure, with GU0.42 ranking the best. Furthermore, PH

samples at w/c of 0.5 show the lowest strength and the highest porosity. Data obtained at 28

days improved statistical fit, with R-square value of 0.84, when compared to samples tested at 3

day.

Furthermore, Figure 5. shows that samples containing PH cement are following the same trend

as the other samples, which indicates that PH cement behaves similarly to OPC and GU cement.

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5.2 Fresh Concrete Properties

5.2.1 Phase II

Table 5.2 presents the fresh state physical properties of each concrete mix design. Although

samples with PH cement show decrease in slump, addition of GGBF improves workability by

increase in slump. Fresh air content results indicate that the same amount of AEA affects PH

concrete differently when compared to GU concrete; In Table 4.4, the same amount of AEA

were used for all the mixes, however results in Table 5.2 indicated that PH-II and PH25S-II

have different fresh air content when compared to GU and GU25S.

Table 5.2: Fresh properties of plastic concrete (Phase II)

Mix # Mix ID Slump

(mm)

Apparent

Air Content

(%)

Air

Content*

(%)

Density (kg/m3)

1 GU-II 127 5.00 4.02 2429

2 GU25S-II 130 5.00 4.02 2409

3 PH-II 97 2.50 1.52 2449

4 PH25S-II 125 2.50 1.52 2438

*Aggregate correction factor of 0.98% is applied.

5.2.2 Phase III

Table 5.3 presents the fresh-state physical properties of each concrete mix design in Phase III.

The four concrete mix designs have a wide range of slump values. The PH concrete had very

low slumps (70-75mm) and the GU cements had markedly higher slumps (160-210 mm). This

drastic difference in slump is believed to be related to difficulty in entraining air and in turn to

the large differences in AEA dosages used. As indicated in Table 4.8, the GU mixtures used

approximately 75 mL of AEA while the PH concrete required 530 mL of AEA per 100 kg of

cement.

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57

Table 5.3: Fresh properties of plastic concrete (Phase III)

Mix # Mix ID Slump

(mm)

Apparent

Air Content

(%)

Air

Content*

(%)

Density (kg/m3)

1 GU-III 210 6.8 5.82 2375

2 GU25S-III 160 5.7 4.72 2399

3 PH-III 70 5.6 4.62 2394

4 PH25S-III 75 5.6 4.62 2396

*Aggregate correction factor of 0.98% is applied.

5.2.3 Phase IV

Table 5.4 presents the fresh properties of the two concrete mixes tested in phase IV. Due to

addition of HRWR, the PH mix slump value is not only closer to that of the GU mix when

compared to the previous phase, but also higher than that of the GU mix. The air contents were

within the 5-8% target, and the densities were similar for both mixes.

Table 5.4: Fresh properties of plastic concrete (Phase IV)

Mix # Mix ID Slump

(mm)

Apparent

Air Content

(%)

Air

Content*

(%)

Density

(kg/m3)

1 GU-IV 170 6.5 5.52 2373

2 PH-IV 192 7.6 6.62 2325

*Aggregate correction factor of 0.98% is applied.

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58

5.2.4 Discussion of the Effects of Mix Design Variables

Air Content (%)

2 4 6 8 10

Slu

mp

(m

m)

60

80

100

120

140

160

180

200

220

GU-II

GU25S-II

PH-II

PH25S-II

GU-III

GU25S-III

PH-III

PH25S-III

GU-IV

PH-IV

Figure 5.4: Air Content vs. Slump

As shown in Figure 5.4, as the air content increases in GU samples, the slump increases too.

However, for PH samples and addition of HRWR is necessary to increase and improve the

slump.

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5.3 Mechanical Properties

5.3.1 Phase II

Results from the compressive strength test are shown in Figure 5.5. For all the concrete

samples, at lower curing ages, it is expected that the presence of GGBFS will reduce the

compressive strength, owing to its latent hydraulic properties. However, addition of the GGBFS

at longer curing age typically enhances the compressive strength.

Although incorporating PH cement reduced compressive strength of the concrete by

approximately 10%, regardless of the curing age, addition of 25% GGBFS improved the

strength in PH samples. Furthermore, all the samples, regardless of the type of cement, show an

increase in compressive strength of approximately 10% with longer curing age.

The density of the samples is shown in Figure 5.6. The density of all the samples was almost the

same, regardless of mix design.

UPV results reflect the homogeneity of the concrete. It should be noted that results might

change with the presence of cracks. As shown in Figure 5.7, although UPV measurements for all

mixes increase linearly with age, samples with PH cement show lower UPV in comparison to

the GU samples due to lower ƒ’c. At age 56 day, all the samples have UPV of approximately

5000 m/s.

The fresh and hardened air content results are shown in Figure 5.8. The hardened air content test

was done to compare the plastic air content with the hardened air content as well as the change

in hardened air content after 28 and 56 days of curing. The results confirm that the plastic air

content could be used as the primary indication for the air content of the concrete. Also, the

results show that the addition of 25% GGBFS results in a decrease of approximately 12 and

15% in the hardened air content of the GU and PH samples after 56 days, respectively. This is

due to the increase in hydration products in the samples with GGBFS.

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Mix ID

GU-II GU25S-II PH-II PH25S-II

Co

mp

ress

ive

Str

eng

th (

MP

a)

0

10

20

30

40

50

60

70

28d

56d

Figure 5.5: Compressive strength of concrete (Phase II)

Note: Each bar represents the average of three measurements

Mix ID

GU-II GU25S-II PH-II PH25S-II

Den

sity

(k

g/m

3)

2100

2200

2300

2400

2500

2600

Fresh

Dry Density (28d)

Dry Density (56d)

Figure 5.6: Density of Concrete (Phase II)

Note: Each symbol represents one measurement for fresh and two measurements for dry density

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61

Mix ID

GU-II GU25S-II PH-II PH25S-II

Ult

raso

lnic

Pu

lse

Vel

oci

ty (

m/s

)

0

1000

2000

3000

4000

5000

6000

28d

56d

Figure 5.7: Ultrasonic pulse velocity (Phase II)

Note: Each bar represents the average of three measurements

Mix ID

GU-II GU25S-II PH-II PH25S-II

Air

Co

nte

nt

(%)

0

1

2

3

4

5

6

Fresh

Hardened (28d)

Hardened (56d)

Figure 5.8: Air content (Phase II)

Note: Each symbol represents one measurement for fresh and the average of two measurements

for hardened concrete.

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5.3.2 Phase III

Compressive strength results at 28 and 56 days are shown in Figure 5.9. By 28 days, all of the

concrete samples achieved compressive strengths of 40 MPa or greater. At 56 days, the PH

concrete demonstrated approximately 5% decrease in compressive strength when compared to

GU concrete. Although addition of 25% GGBFS improved the strength in both GU and PH

samples, PH25S-III showed 13% decrease in strength when compared to GU25S-III.

The density of the samples is shown in Figure 5.10. The density of all the samples at 56 days is

within a range of 2200 to 2300 kg/m3, which reflects normal density concrete. As shown in

Figure 5.11, the UPV measurements for all mixes at age 56 day are in a narrow range of

approximately 4700 to 4900 m/s. This range of UPV measurements is typical for dense,

homogeneous concrete with compressive strengths greater than 40 MPa.

Mix ID

GU-III GU25S-III PH-III PH25S-III

Co

mp

ress

ive

Str

eng

th (

MP

a)

0

20

40

60

28d

56d

Figure 5.9: Compressive strength of concrete (Phase III)

Note: Each bar represents the average of three measurements and the error bar represents

standard deviation

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63

Mix ID

GU-III GU25S-III PH-III PH25S-III

Den

sity

(k

g/m

3)

2100

2200

2300

2400

2500

2600

Fresh

Dry Density (28d)

Dry Density (56d)

Figure 5.10: Density of concrete (Phase III)

Note: Each symbol represents one measurement for fresh and two measurements for dry density

Mix ID

GU-III GU25S-III PH-III PH25S-III

UP

V (

m/s

)

0

1000

2000

3000

4000

5000

6000

28d

56d

Figure 5.11: Ultrasonic pulse velocity (Phase III)

Note: Each bar represents three measurements and the error bar represents standard deviation

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64

Given the difficulty in entraining air in the PH concrete, the hardened air void content was

further examined. Table 5.5 shows additional information on the air characterization of the GU

and PH mixes. All mixes have the hardened air content of 5- 6.6%, the spacing factor of 0.11-

0.18 mm, and the specific surface of 33-39 mm2/mm

3 and the results were within an acceptable

limit. Figure 5.12 presents the fresh air content plotted with the hardened air content at 56 days.

The results show similar fresh and hardened air content measurements for all mixtures, falling

between target air content of 5-8%. This result confirms the plastic air content measurements

and will play an important factor for the freeze-thaw durability performance.

Table 5.5: Air content characterization (Phase III)

Mix ID

Apparent

Air

Content

(%)

Fresh

Air

Content*

(%)

Hardened

Air Content

(%)

Specific

Surface

(mm2/mm

3

of air)

Spacing

Factor

(mm)

Void

Frequency

(intercepts/mm)

28d 56d 28d 56d 28d 56d 28d 56d

Average of Two Measurements

GU-III 6.8 5.82 6.54 6.56 34.07 39.23 0.13 0.12 0.48 0.70

GU25S-

III 5.7 4.72 5.07 5.83 35.42 39.25 0.14 0.11 0.46 0.61

PH-III 5.6 4.62 5.18 5.36 34.31 30.51 0.16 0.18 0.41 0.38

PH25S-

III 5.60 4.62 5.28 5.36 33.13 33.13 0.16 0.15 0.45 0.42

*Aggregate correction factor of 0.98% is applied.

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65

Mix ID

GU-III GU25S-III PH-III PH25S-III

Air

Con

tent

(%)

0

2

4

6

8

10

Fresh

Hardened (28d)

Hardened (56d)

Figure 5.12: Air content of concrete (Phase III)

Note: Each symbol represents ones measurements for fresh and the average of two

measurements for hardened concrete.

5.3.3 Phase IV

Results from the compressive strength test at 28 days are shown in Figure 5.13. By 28 days, GU

sample achieved compressive strengths of approximately 45 MPa, which is higher than the

previous phase by more than 6%, while PH sample resulted in a lower compressive strength of

approximately 35 MPa, which is lower by more than 14%.

The 28 day UPV measurements, shown in Figure 5.14, for all mixes are in generally lower

range (4400 to 4800m/s) in comparison to the previous phase III (4700 to 4900m/s). This is

expected since Phase IV concrete has relatively higher air content (6.5 to 8%) in comparison to

the air content of the concrete in Phase III (5.6 to 6.8%).

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66

Mix ID

GU-IV PH-IV

Co

mp

ress

ive

Str

eng

th (

MP

a)

0

20

40

60

28d

Figure 5.13: Compressive strength of concrete (Phase IV)

Note: Each bar represents the average of three measurements and the error bar represents

standard deviation

Mix ID

GU-IV PH-IV

UP

V (

m/s

)

0

1000

2000

3000

4000

5000

6000

28d

Figure 5.14: Ultrasonic pulse velocity (Phase IV)

Note: Each bar represents three measurements and the error bar represents standard deviation

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Table 5.6 shows additional information on the air characterization of the GU and PH mixes.

Figure 5.15 presents the fresh air content and the hardened air content at 28 days. The results

show similar fresh and hardened air content measurements for all mixtures, falling between 6.5-

8%.

Previously, in Phase III, AirExtra was used as an AEA. Although the hardened air content of the

GU samples are almost the same, when compared to Phase III, using different brand of AEA

and addition of HRWR results in an increase in both spacing factor and the specific surface of

air. For PH samples, when compared to the previous page, increase in both fresh and hardened

air content results in decrease of both spacing factor and specific surface of air.

Table 5.6: Air content characterization (Phase IV)

Mix

ID

Apparent

Air

Content

(%)

Fresh

Air

Content*

(%)

Hardened

Air Content

(%)

Specific

Surface

(mm2/mm

3 of

air)

Spacing

Factor

(mm)

Void Frequency

(intercepts/mm)

28d 28d 28d 28d

Average of Two Measurements

GU-IV 6.5 5.52 6.51 22.6 0.19 0.37

PH-IV 7.6 6.62 8.04 25.44 0.15 0.5

*Aggregate correction factor of 0.98% is applied.

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68

Mix ID

GU-IV PH-IV

Air

Con

tent

(%)

0

2

4

6

8

10

Fresh

Hardened (28d)

Figure 5.15: Air content of concrete (Phase IV)

Note: Each symbol represents ones measurements for fresh and the average of two

measurements for hardened concrete.

28d Hardened Air Content (%)

2 4 6 8 10

28

d C

om

pre

ssiv

e S

tren

gth

(M

Pa)

30

35

40

45

50

55

60

GU-II

GU25S-II

PH-II

PH25S-II

GU-III

GU25S-III

PH-III

PH25S-III

GU-IV

PH-IV

Figure 5.16: Influence of air content on compressive strength (28d)

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5.3.4 Discussion of the Effects of Mix Design Variables

As shown in Figure 5.16, for both GU and PH samples, there is a decrease in compressive

strength with an increase in the air content. Utilizing different brand of AEA and addition of

HRWR improves the strength of GU sample with no effect on the hardened air content, while it

reduces the strength in PH sample and increases its air content.

5.4 Transport Properties

5.4.1 Phase II

The RCPT results, shown in Figure 5.17, indicate that the chloride permeability of all the mixes

with 25% GGBFS are less than 2000 Coulombs. PH samples show the highest chloride

permeability.

Mix ID

GU-II GU25S-II PH-II PH25S-II

Ad

just

ed c

har

ge

pas

sed (

Co

ulo

mb

s)

0

2000

4000

6000

28d

56d

Figure 5.17: Rapid chloride permeability of concrete (Phase II)

Note: Each bar represents the average of two measurements

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5.4.2 Phase III

The RCPT results are shown in Figure 5.18. Both the GU25S and the PH25S have similar

RCPT values at 28 and 56 days. At 28 days, the RCPT of the GU and PH concrete is similar.

For all mixtures, the RCPT decreases with age as expected.

The initial sorptivity of finished and formed surfaces at 28 and 56 days are shown in Figure 5.19

and Figure 5.20, respectively. It is apparent that there is a greater sorptivity for finished (top)

surfaces in comparison to formed (bottom) surfaces. This is attributed to a more porous surface

layer in finished surface than to that of formed. As expected, the sorptivity coefficient of the

finished surface was greater than that of the formed surface, while this rate decreased with

higher curing period. Concrete with PH cement did not have any effect on the sorptivity

coefficient. The addition of 25% GGBFS resulted in an increase in initial sorptivity rate of both

GU and PH specimens.

Mix ID

GU-III GU25S-III PH-III PH25S-III

RC

PT

(C

ou

lom

bs)

0

2000

4000

6000

28d

56d

Figure 5.18: Rapid chloride permeability of concrete (Phase III)

Note: Each bar represents the average of two measurements, except for PH at 28d (three

measurements)

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Init

ial

So

rpti

vit

y (

x1

0-4

mm

/sec

1/2

)

MIX ID

GU-III GU25S-III PH-III PH25S-III

0

10

20

30

40

50

Finished

Formed

Figure 5.19: Initial sorptivity of finished and formed surface concrete at 28 days (Phase

III)

Note: Each bar represents the average of three measurements

MIX ID

GU-III GU25S-III PH-III PH25S-III

Init

ial

So

rpti

vit

y (

x1

0-4

mm

/sec

1/2

)

0

10

20

30

40

50

Finished

Formed

Figure 5.20: Initial sorptivity of finished and formed surface concrete at 56 days (Phase

III)

Note: Each bar represents the average of three measurements

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72

5.4.3 Phase IV

Figure 5.21 shows the RCPT results for phase IV mixes. At 28 days, when compared to phase

III, the RCPT of both GU and PH is high. The relative increase in RCPT results is higher for PH

and this can be related to the improvement in the pore structure of the samples in Phase IV.

The initial rate of absorption of the samples followed the same trend; higher than that found in

the previous phase, especially in the formed surface samples.

Mix ID

GU-IV PH-IV

RC

PT

(C

ou

lom

bs)

0

1000

2000

3000

4000

5000

6000

28d

Figure 5.21: Rapid chloride permeability of concrete (Phase IV)

Note: Each bar represents the average of two measurements

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73

Init

ial

So

rpti

vit

y (

x1

0-4

mm

/sec

1/2

)

MIX ID

GU-IV PH-IV

0

10

20

30

40

50

Finished

Formed

Figure 5.22: Initial sorptivity of finished and formed surface concrete at 28 days (Phase

IV)

Note: Each bar represents the average of three measurements

28d Hardened Air Content (%)

0 2 4 6 8 10

28

d R

CP

T (

Co

ulo

mb

s)

0

2000

4000

6000

GU-II

GU25S-II

PH-II

PH25S-II

GU-III

GU25S-III

PH-III

PH25S-III

GU-IV

PH-IV

Figure 5.23: Influence of air content on RCPT results at 28d

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74

5.4.4 Discussion of the Effects of Mix Design Variables

As shown in Figure 5.23, the RCPT results for all the PH samples are about or higher than 4000

coulombs, despite of the amount of AEA used. This can be due the TiO2 in the photocatalytic

cement, which acts as a semiconductor. This demonstrates that RCPT test may not be

appropriate testing photocatalytic concrete.

Since the RCPT test is related to capillary absorption, the samples need to maintain a continuous

liquid phase for chloride ingress. For GU samples, utilizing different brand of AEA and addition

of HRWR improves the pore structure development of the concrete samples.

5.5 Durability Properties

5.5.1 Phase III

Results from the resistance to salt scaling test for finished and formed surfaces are shown in

Figure 5.24 and Figure 5.25, respectively. Based on the results of up to 50 freeze-thaw cycles,

the finished surface scaled more than the formed surface for the same concrete mix design. As

expected, the poorer scaling performance of the finished surface is attributed to the effects of

bleed water and/or variations in surface microstructure due to the finishing technique. For both

the finished and the formed surface, the PH and PH25S exhibit greater mass losses. The

influence of the fine particle size of the TiO2 on surface scaling may be a potential explanation

but needs to be examined further.

Figure 5.24 shows that the finished surface of PH and PH25S concrete exhibits much greater

scaling losses compared to GU and GU25S even after 5 freeze thaw cycles, at which point they

had already exceeded the 0.80 kg/m2 OPSS 1351 acceptance limit. Figure 5.25 shows that for

the formed surface, although the PH mixtures are scaling more than the GU concrete, the

cumulative mass loss after 50 freeze-thaw cycles is less than the OPSS limit of 0.80 kg/m2.

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As expected, the concrete containing 25% GGBFS exhibited greater scaling mass loss compared

to those without GGBFS, irrespective of whether GU or PH cements were used and whether the

formed or finished surface was tested. Theories of the influence of GGBFS on salt scaling are

well reported in literature and will not be discussed in this report (Copuroglu, 2006; Boyd and

Hooton, 2007; Valenza and Sherer, 2006).

In terms of visual ranking, based on ASTM C672, as shown in Figures 5.26 and 5.27, for

finished surface samples, GU samples are closer to visual rating of 2, while PH samples can be

ranked at 5. For formed surfaces, as shown in Figures 5.28 and 5.29, GU samples had a visual

ranking of 1 and the PH samples had a visual ranking of 4.

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76

Cycles

0 10 20 30 40 50 60

Cum

ula

tive

Mas

s L

oss

(K

g/m

2)

0

1

2

3

4

GU-Fin

GU25S-Fin

PH-Fin

PH25S-Fin

MTO Limit (0.80)

Figure 5.24: Salt scaling mass loss of finished surface (Phase III)

Note: Each symbol represents the average of two measurements

Cycles

0 10 20 30 40 50 60

Cum

ula

tive

Mas

s L

oss

(K

g/m

2)

0

1

2

3

4

GU-For

GU25S-For

PH-For

PH25S-For

MTO Limit (0.80)

Figure 5.25: Salt scaling mass loss of formed surface (Phase III)

Note: Each symbol represents the average of two measurements

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77

Figure 5.26: GU concrete (finished surface) after 50 freeze-thaw cycle (Phase III)

Figure 5.27: PH concrete (finished surface) after 50 freeze-thaw cycle (Phase III)

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78

Figure 5.28: GU concrete (formed surface) after 50 freeze-thaw cycle (Phase III)

Figure 5.29: PH concrete (formed surface) after 50 freeze-thaw cycle (Phase III)

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79

Rapid freeze/thaw testing was used to evaluate the durability factor of the prisms. Figure 5.30

illustrates the durability factors that were calculated in accordance with the recommendation is

ASTM C666 after 300 freeze/thaw cycles. The durability factors range from 92% to 97%. This

reveals that all mix designs are resisting damage well.

Figure 5.31 and Figure 5.32 show the appearance and conditions of the prisms after 300 rapid

freeze-thaw cycles.

Mix ID

GU GU25S PH PH25S

Du

rab

ilit

y F

acto

r (%

)

0

20

40

60

80

100

Figure 5.30: Durability factor after 300 rapid freeze-thaw cycles (Phase III)

Note: Each bar represents the average of two measurements

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80

Figure 5.31: GU and GU+25%GGBFS prisms after 300 rapid freeze-thaw cycles (Phase III)

Figure 5.32: PH and PH+25%GGBFS prisms after 300 rapid freeze-thaw cycles (Phase III)

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81

5.5.2 Phase IV

Results from the resistance to salt scaling test are shown in Figures 5.33 and 5.34 for the

finished and formed surface, respectively. Based on the results the finished surface of both mix

GU and PH mixes already exceeded the 0.80 kg/m2

OPSS 1351 acceptable limit just after the

first 5 freeze-thaw cycles. For the formed surface, the PH mixtures are scaling less than the GU

concrete and the cumulative mass loss after 50 freeze-thaw cycles is well below the OPSS limit

of 0.80 kg/m2.

In terms of visual ranking, based on ASTM C672, as shown in Figures 5.26 and 5.27, for

finished surface samples, both GU and PH samples were closer to visual rating of 4, while the

GU formed surface and PH formed surface, as shown in Figures 5.28 and 5.29, had a visual

ranking of 3 and 1, respectively.

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82

Cycles

0 10 20 30 40 50 60

Cum

ula

tive

Mas

s L

oss

(K

g/m

2)

0

1

2

3

4

GU-Fin-IV

PH-Fin-IV

MTO Limit (0.8)

Figure 5.33: Salt scaling mass loss of finished surface (Phase IV)

Cycles

0 10 20 30 40 50 60

Cum

ula

tive

Mas

s L

oss

(K

g/m

2)

0

1

2

3

4

GU-For-IV

PH-For-IV

MTO Limit (0.8)

Figure 5.34: Salt scaling mass loss of formed surface (Phase IV)

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83

Figure 5.35: GU concrete (finished surface) after 50 freeze-thaw cycle (Phase IV)

Figure 5.36: PH concrete (finished surface) after 50 freeze-thaw cycle (Phase IV)

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84

Figure 5.37: GU concrete (formed surface) after 50 freeze-thaw cycle (Phase IV)

Figure 5.38: PH concrete (formed surface) after 50 freeze-thaw cycle (Phase IV)

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85

5.5.3 Effects of Mix Design Variables

As shown in Figures 5.39 and 5.40, the addition of HRWR resulted in improved salt-scaling

resistance for PH samples with formed surfaces while it had an opposite effect on finished

surfaces for both GU and PH.

0 2 4 6 8 10

0

1

2

3

4

GU-III

GU25S-III

PH-III

PH25S-III

GU-IV

PH-IV

Hardened Air Content (%)

Cum

mu

lati

ve

Mas

s L

oss

(K

g/m

2)

Figure 5.39: Influence of air content on salt-scaling for finished surface after 50 cycles

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86

0 2 4 6 8 10

0

1

2

3

4

GU-III

GU25S-III

PH-III

PH25S-III

GU-IV

PH-IV

Hardened Air Content (%)

Cum

mu

lati

ve

Mas

s L

oss

(K

g/m

2)

Figure 5.40: Influence of air content on salt-scaling for formed surface 50 cycles

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87

Chapter 6 Conclusion

Photocatalytic concrete is a rapidly emerging and innovative technology in material science that

exhibits self-cleaning and pollution-abating properties owing to the presence of titanium

dioxide. Although the pollution-abating effectiveness of photocatalytic concrete has been

proven in laboratory and field studies around the world, a close examination of the material

properties have not been reported as widely.

Key conclusions from this study include:

For Hamilton MT station, the NO abatement estimates of photocatalytic concrete are:

o For a relatively lower abatement rate (6 mg/h/m2), a maximum NO abatement

rate of 20% is achieved. This estimate is calculated based on the eleven year

average NO concentration of 30 mg/h/m2 for the month of July.

o For a relatively higher abatement rate (20 mg/h/m2), a maximum NO abatement

rate of 67%. This estimate is calculated based on the eleven year average NO

concentration of 30 mg/h/m2 for the month of July.

In Toronto, for a 20 mg/h/m2 abatement rate of photocatalytic concrete, estimated range

of 3% to 24% NO removal efficiency can be achieved. In general, these estimates fall

within 20-80% range of pollution abatement effectiveness reported in the literature.

The mechanical and fluid transport properties of photocatalytic concrete are

comparable to conventional GU concrete:

o In Phase III at 28 days, where hardened air contents for GU concrete is 6.5%

and for PH concrete is 5.2%, with total cementitious material of 429 k/m3 and

water to cement ratio of 0.42, the compressive strength ranges between 39-48

MPa.

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88

o In Phase IV at 28 days, where hardened air content for GU concrete is 6.5%

and for PH concrete is 7.6%, with total cementitious material of 429 k/m3 and

water to cement ratio of 0.42 plus the addition of HRWR, the compressive

strength of the photocatalytic concrete decreased by approximately 13% while

the compressive strength of the GU concrete increased by approximately 6%

when compared to phase III. The decrease in compressive strength of the

photocatalytic concrete could be explained by the increase in the air content.

o RCPT values in different phases gave inconsistent results.

Air was much more difficult to entrain in photocatalytic concrete compared to GU

concrete. However, with 5% to 7% air, photocatalytic concrete can achieve good

freeze-thaw resistance, comparable to air-entrained GU concrete.

In terms of de-icer salt scaling performance:

o Formed surface performed well and achieved relatively lower mass loss.

Although formed surface PH concrete mass loss was greater than that of GU, it

was still below 0.8 even after 50 cycles.

o Highly variable results for PH and GU concrete was observed for the finished

surface. This is particularly important because photocatalytic concrete is only

economically feasible if it is applied as a cover.

o Utilizing different brands of AEA with addition of HRWR improved the

scaling performance of the photocatalytic concrete for the formed surface.

Possible explanations are the relatively higher air content and a better

workability (higher slump).

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89

Chapter 7 Recommendations for Future Work

Further research is necessary to investigate why photocatalytic concrete performs poorer than

conventional concrete in the salt-scaling test.

This can be done by investigating different methods for surface finishes as well as utilizing

different admixtures to optimize the entrained air content. Until this is resolved, it is suggested

that photocatalytic concrete should be restricted from de-icer salt expose. Admixtures need to

be evaluated to ensure that they do not decrease the effectiveness of the photocatalytic activity

of concrete.

Furthermore, due to inconclusive RCPT results, other tests should be carried out in order to

investigate the penetration resistance of the photocatalytic concrete.

F

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Appendix A: Hourly Pollution Data for Toronto E Station

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

O3 (

ppb)

0

10

20

30

40

50

60May

Jun

Jul

Aug

Sep

Figure A.1: Toronto E O3 hourly data from May to Sept (2000-2011)

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

O3 (

ppb)

0

10

20

30

40

50

60Oct

Nov

Dec

Jan

Feb

Mar

Apr

Figure A.2: Toronto E O3 hourly data from Oct to April (2000-2011)

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98

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

NO

x (

ppb)

0

10

20

30

40

50

60May

Jun

Jul

Aug

Sep

Figure A.3: Toronto E NOx hourly data from May to Sept (2000-2011)

Hour

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

H22

H23

H24

NO

x (

ppb

)

0

20

40

60

Oct

Nov

Dec

Jan

Feb

Mar

Apr

Figure A.4: Toronto E NOx hourly data from Oct to April (2000-2011)

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99

Appendix B: Monthly Pollution Data for Cities with the Greatest Number of Smog Advisories in Ontario

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

O3 (

pp

b)

0

10

20

30

40

50

60Windsor DT

Hamilton MT

Port Stanley

Oshawa

Brantford

Sarnia

Figure B.1: Average monthly O3 concentration (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

O3 (

ppb

)

0

10

20

30

40

50

60Toronto DT

Toronto W

Toronto E

Toronto N

Figure B.2: Average monthly O3 concentration for Toronto (2000-2011)

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100

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

x (

ppb)

0

10

20

30

40

50

60Windsor DT

Hamilton MT

Oshawa

Brantford

Sarnia

Figure B.3: Average monthly NOx concentration (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

x (

ppb)

0

10

20

30

40

50

60

Toronto DT

Toronto W

Toronto E

Toronto N

Figure B.4: Average monthly NOx concentration for Toronto (2000-2011)

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101

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

2 (

pp

b)

0

10

20

30

40

50

60

Windsor DT

Hamilton MT

Oshawa

Brantford

Sarnia

Figure B.5: Average monthly NO2 concentration (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

2 (

pp

b)

0

10

20

30

40

50

60

Toronto DT

Toronto W

Toronto E

Toronto N

Figure B.6: Average monthly NO2 concentration for Toronto (2000-2011)

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102

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

(p

pb

)

0

10

20

30

40

50

60

Windsor DT

Hamilton MT

Oshawa

Brantford

Sarnia

Figure B.7: Average monthly NO concentration (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NO

(p

pb

)

0

10

20

30

40

50

60

Toronto DT

Toronto E

Toronto N

Toronto W

Figure B.8: Average monthly NO concentration for Toronto (2000-2011)

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103

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

µg/m

3

0

5

10

15

20

25

30

Windsor DT

Hamilton MT

Oshawa

Brantford

Sarnia

Figure B.9: Average monthly PM2.5 concentration (2000-2011)

Month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

µg/m

3

0

5

10

15

20

25

30

Toronto DT

Toronto W

Toronto E

Toronto N

Figure B.10: Average monthly PM2.5 concentration for Toronto (2000-2011)

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104

Appendix C: Pollution Conversion (ppb to mg/h/m2)

Table C.1: Toronto DT

[NO] Average wind speed

Toronto

Average

Air

Temp TORONTO DT

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 10 19 19000 -2 10.30 0.0139 263.86

FEB 12 22 22000 -1 10.01 0.0134 295.82

MAR 11 20 20000 6 7.62 0.0100 199.55

APR 12 22 22000 8 5.83 0.0076 166.78

MAY 8 15 15000 17 4.87 0.0061 91.99

JUN 10 19 19000 21 4.47 0.0056 105.57

JUL 9 17 17000 26 4.02 0.0049 83.63

AUG 9 17 17000 23 4.67 0.0058 98.04

SEP 8 15 15000 19 5.85 0.0073 109.90

OCT 10 19 19000 12 9.40 0.0121 229.14

NOV 9 17 17000 8 10.35 0.0135 228.89

DEC 11 20 20000 0 9.34 0.0125 250.07

Table C.2: Toronto W

[NO] Average wind speed

Toronto

Average

Air

Temp TORONTO W

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 10 19 19000 -2 20.98 0.0283 537.60

FEB 12 22 22000 -1 23.16 0.0311 684.68

MAR 11 20 20000 6 20.65 0.0271 541.09

APR 12 22 22000 8 15.35 0.0200 439.11

MAY 8 15 15000 17 13.35 0.0168 252.32

JUN 10 19 19000 21 11.39 0.0142 269.02

JUL 9 17 17000 26 10.96 0.0134 227.75

AUG 9 17 17000 23 13.78 0.0170 289.24

SEP 8 15 15000 19 18.28 0.0229 343.27

OCT 10 19 19000 12 24.06 0.0309 586.29

NOV 9 17 17000 8 27.71 0.0360 612.61

DEC 11 20 20000 0 21.35 0.0286 571.70

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105

Table C.3: Toronto E

[NO] Average wind speed

Toronto

Average

Air

Temp TORONTO E

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 10 19 19000 -2 18.29 0.0247 468.73

FEB 12 22 22000 -1 18.49 0.0248 546.44

MAR 11 20 20000 6 14.35 0.0188 375.92

APR 12 22 22000 8 9.73 0.0127 278.47

MAY 8 15 15000 17 8.27 0.0104 156.42

JUN 10 19 19000 21 7.67 0.0095 181.13

JUL 9 17 17000 26 7.06 0.0086 146.70

AUG 9 17 17000 23 8.86 0.0109 185.89

SEP 8 15 15000 19 12.27 0.0154 230.38

OCT 10 19 19000 12 17.34 0.0222 422.47

NOV 9 17 17000 8 20.45 0.0266 452.21

DEC 11 20 20000 0 17.56 0.0235 470.22

Table C.4: Toronto N

[NO] Average wind speed

Toronto

Average

Air

Temp TORONTO N

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 10 19 19000 -2 14.04 0.0189 359.81

FEB 12 22 22000 -1 13.86 0.0186 409.62

MAR 11 20 20000 6 11.53 0.0151 302.18

APR 12 22 22000 8 8.47 0.0110 242.41

MAY 8 15 15000 17 6.81 0.0086 128.71

JUN 10 19 19000 21 5.52 0.0069 130.42

JUL 9 17 17000 26 4.49 0.0055 93.22

AUG 9 17 17000 23 5.47 0.0068 114.92

SEP 8 15 15000 19 8.20 0.0103 153.92

OCT 10 19 19000 12 13.40 0.0172 326.42

NOV 9 17 17000 8 16.91 0.0220 373.87

DEC 11 20 20000 0 14.20 0.0190 380.17

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106

Table C.5: Windsor DT

[NO] Average wind speed

Windsor

Average

Air

Temp Windsor DT

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 11 20 20000 -2 12.74 0.0172 343.70

FEB 10 19 19000 0 11.93 0.0160 303.34

MAR 10 19 19000 5 8.81 0.0116 220.02

APR 12 22 22000 11 5.05 0.0065 142.97

MAY 9 17 17000 18 4.51 0.0057 96.26

JUN 9 17 17000 23 4.06 0.0050 85.26

JUL 8 15 15000 25 3.16 0.0039 58.08

AUG 8 15 15000 24 4.31 0.0053 79.57

SEP 8 15 15000 20 6.38 0.0080 119.33

OCT 9 17 17000 14 10.09 0.0128 218.34

NOV 10 19 19000 7 12.89 0.0168 319.58

DEC 10 19 19000 0 14.28 0.0191 363.35

Table C.6: Oshawa

[NO] Average wind speed

Oshawa

Average

Air

Temp Oshawa

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 9 17 17000 -3 7.97 0.0108 183.39

FEB 10 19 19000 -1 8.71 0.0117 222.3381

MAR 10 19 19000 5 7.36 0.0097 183.72

APR 10 19 19000 8 5.51 0.0072 136.26

MAY 8 15 15000 16 4.98 0.0063 94.48

JUN 9 17 17000 20 4.35 0.0054 92.18

JUL 7 13 13000 24 3.51 0.0043 56.19

AUG 7 13 13000 22 3.55 0.0044 57.25

SEP 7 13 13000 20 4.69 0.0059 76.06

OCT 8 15 15000 12 8.04 0.0103 154.66

NOV 7 13 13000 7 10.46 0.0137 177.53

DEC 8 15 15000 1 9.97 0.0133 199.42

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107

Table C.7: Hamilton MT

[NO] Average wind speed

Hamilton

Average

Air

Temp Hamilton MT

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 5 9 9000 0 10.44 0.0140 125.7994

FEB 5 9 9000 1 12.01 0.0160 144.1651

MAR 6 11 11000 6 9.15 0.0120 131.8332

APR 6 11 11000 9 7.64 0.0099 108.9826

MAY 5 9 9000 16 6.84 0.0087 77.8584

JUN 5 9 9000 21 4.72 0.0059 52.8643

JUL 4 7 7000 27 3.53 0.0043 30.0724

AUG 4 7 7000 24 4.26 0.0052 36.6691

SEP 4 7 7000 19 7.38 0.0092 64.6683

OCT 4 7 7000 12 11.52 0.0148 103.3916

NOV 5 9 9000 9 14.89 0.0193 173.6982

DEC 4 7 7000 2 11.51 0.0153 107.0664

Table C.8: Brantford

[NO] Average wind speed

Oxford Lake

Average

Air

Temp Brantford

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 5 9 9000 1 10.44 0.0139 125.3405

FEB 5 9 9000 13 12.01 0.0153 138.1194

MAR 5 9 9000 10 9.15 0.0118 106.3398

APR 3 6 6000 19 7.64 0.0096 57.4103

MAY n/a n/a n/a 6.84

JUN n/a n/a n/a 4.72

JUL n/a n/a n/a 3.53

AUG n/a n/a n/a 4.26

SEP n/a n/a n/a 7.38

OCT n/a n/a n/a 11.52

NOV n/a n/a n/a 14.89

DEC n/a n/a n/a 11.51

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108

Table C.9: Sarnia

[NO] Average wind speed

Blackwell/Sarnia (SARNIA)

Average

Air

Temp Sarnia

Month Knots km/h m/h ºC (ppb) (mg/m3) (mg/h/m

2)

JAN 11 20 20000 -3 5.70 0.0077 154.3496

FEB 12 22 22000 -1 5.88 0.0079 173.8628

MAR 11 20 20000 4 3.99 0.0053 105.3741

APR 13 24 24000 9 3.33 0.0043 103.7213

MAY 10 19 19000 15 3.07 0.0039 74.0867

JUN 9 17 17000 20 3.32 0.0041 70.4415

JUL 8 15 15000 23 3.19 0.0039 59.0529

AUG 8 15 15000 22 2.95 0.0037 54.7678

SEP 9 17 17000 18 3.43 0.0043 73.1834

OCT 10 19 19000 12 4.66 0.0060 113.4253

NOV 10 19 19000 7 6.71 0.0088 166.3340

DEC 11 20 20000 0 6.40 0.0086 171.3059

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109

Appendix D: Test Data

D.1 Phase II

Table D.1: Compressive Strength (Phase II)

MIX

ID

Curing

Age

(Day)

Compressive Strength (CSA.A23.2-9C)

Strength

Reading

(KN)

Strength

Reading

(Mpa)

Average

(MPa) St.Dev

Co.V.

(%)

GU

28

392.8 48.07

48.43 0.37 0.76 398.8 48.81

395.5 48.41

56

437.1 53.49

52.46 1.41 2.70 433.5 53.05

415.5 50.85

G25S

28

436.3 53.40

52.48 2.01 3.82 410.0 50.18

440.1 53.86

56

468.3 57.31

58.17 0.90 1.55 483.0 59.11

474.8 58.10

PH

28

351.8 43.05

42.12 1.58 3.76 351.5 43.01

329.2 40.29

56

383.4 46.92

46.92 0.16 0.33 382.2 46.77

384.7 47.08

PH25S

28

418.4 51.20

51.84 0.55 1.06 426.2 52.16

426.2 52.15

56

468.8 57.37

56.14 1.17 2.08 449.8 55.05

457.7 56.01

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110

Table D.2: Ultrasonic Pulse Velocity (Phase II)

MIX ID

Curing

Age

(Day)

UPV (ASTM C 597)

Length

(mm)

UPV

Reading

(µSec)

Pulse

Velocity

(m/s)

Average

Pulse

Velocity

(m/s)

St.Dev. Co.V.

(%)

GU

28

197 40.4 4.88×103

4859.5 14.5 0.30 195 40.2 4.85×103

196 40.4 4.85×103

56

199 40.2 4.95×103

5001.4 99.7 1.99 198 40.1 4.94×103

198 38.7 5.12×103

G25S

28

197 42.4 4.65×103

4654.1 12.2 0.26 198 42.6 4.65×103

197 42.2 4.67×103

56

197 38.8 5.08×103

5035.6 119.7 2.38 199 38.8 5.13×103

197 40.2 4.90×103

PH

28

196 42.0 4.67×103

4645.8 21.1 0.45 197 42.6 4.62×103

197 42.4 4.65×103

56

200 40.2 4.97×103

4917.5 51.3 1.04 197 40.2 4.90×103

198 40.6 4.88×103

PH25S

28

197 44.2 4.46×103

4456.2 21.4 0.48 196 44.2 4.43×103

197 44.0 4.48×103

56

200 40.0 5.00×103

4917.4 122.1 2.48 193 40.4 4.78×103

200 40.2 4.97×103

Page 124: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

111

Table D.3: Mass Measurements for Density (Phase II)

MIX

ID

Curing

Age

(Day)

Section

Density (CSA A23.2-11C)

Diameter

average

(mm)

Volume

(mm3)

Average

Oven

Dry

Mass

A

(Kg)

Average

Submerged

Mass

B

(Kg)

Average

Boiled

Mass

C

(Kg)

Average

Suspended

Mass

D

(Kg)

GU

28

1

102.52 8.25×105 1.88 1.97 1.97 1.12

2

3

4

56

1

102.19 8.20×105 1.85 1.97 1.97 1.12

2

3

4

GU25S

28

1

102 8.17×105 1.88 1.95 1.95 1.11

2

3

4

56

1

101.86 8.14×105 1.84 1.95 1.95 1.11

2

3

4

PH

28

1

102.68 8.28×105 1.89 1.97 1.97 1.13

2

3

4

56

1

102.02 8.17×105 1.83 1.94 1.94 1.10

2

3

4

PH25S

28

1

102.13 8.19×105 1.87 1.94 1.94 1.11

2

3

4

56

1

102.08 8.18×105 1.84 1.97 1.97 1.12

2

3

4

Page 125: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

112

Table D.4: Absorption and Density (Phase II)

MIX ID

Curing

Age

(Day)

absorption

(after

immersion)

%

absorption

(after

immersion and

boiling)

%

Dry Density

(Oven-dried)

Kg/m3

Density

(after

immersion)

Kg/m3

Density

(after immersion

and boiling)

Kg/m3

GU 28 4.65 4.65 2222.3 2325.7 2325.6

56 6.31 6.30 2187.6 2325.8 2325.6

GU25S 28 3.63 3.64 2244.0 2325.4 2325.6

56 6.15 6.13 2191.2 2325.9 2325.6

PH 28 4.48 4.47 2226.1 2325.7 2325.6

56 5.51 5.51 2204.1 2325.6 2325.6

PH25S 28 3.64 3.61 2244.4 2326.1 2325.6

56 7.23 7.20 2169.3 2326.2 2325.6

Table D.5: Rapid Chloride Permeability (Phase II)

MIX

ID

Curing

Age

(Day)

Section

RCPT (ASTM C 1202)

Average

Diameter

(mm)

Total

Charge

Passed

Average

Adjusted

Charge

Passed

Average St.Dev Co.V.

(%)

GU

28 1 102.8 3397

3661.5 2947

3176.5 324 10.22 2 102.30 3926 3406

56 1 102.81 2929

3069 2541

2662.5 171 6.45 2 102.33 3209 2784

GU25S

28 1 102.32 1719

1709 1491

1482.5 12 0.81 2 102.15 1699 1474

56 1 102.05 1192

1216 1034

1055 30 2.82 2 102.03 1240 1076

PH

28 1 102.54 7093

6239.5 6153

5412.5 1047 19.35 2 102.49 5386 4672

56 1 102.22 5752

5168.5 4990

4483.5 716 15.98 2 101.71 4585 3977

PH25S

28 1 102.20 2298

2298.5 1993

2013.5 29 1.44 2 101.68 2299 2034

56 1 102.29 1757

1661.5 1524

1441 117 8.15 2 101.82 1566 1358

Page 126: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

113

D.2 Phase III

Table D.6: Compressive Strength (Phase III)

MIX

ID

Curing

Age

(Day)

Compressive Strength (CSA.A23.2-9C)

Strength

Reading

(KN)

Strength

Reading

(Mpa)

Average

(MPa) St.Dev.

Co.V.

(%)

GU

28

352.1 43.09

42.24 0.64 1.53 339.3 41.53

344.0 42.10

56

365.7 44.75

45.45 0.49 1.08 374.2 45.80

374.2 45.79

G25S

28

392.3 48.01

46.37 1.19 2.56 374.8 45.87

369.6 45.23

56

424.9 52.00

51.88 0.71 1.37 416.4 50.96

430.6 52.69

PH

28

321.3 39.32

39.74 0.65 1.64 332.2 40.66

320.7 39.24

56

352.1 42.25

42.90 1.03 2.41 350.8 42.10

369.6 44.36

PH25S

28

336.1 41.14

41.63 0.36 0.87 343.3 42.01

341.0 41.73

56

370.4 45.33

44.77 1.49 3.34 378.0 46.26

349.2 42.73

Page 127: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

114

Table D.7: Ultrasonic Pulse Velocity (Phase III)

MIX

ID

Curing

Age

(Day)

UPV (ASTM C 597)

Length

(mm)

UPV

Reading

(µSec)

Pulse

Velocity

(m/s)

Average

Pulse

Velocity

(m/s)

St.Dev. Co.V.

(%)

GU

28

195 42.2 4.62×103

4.71×103 99.79 2.12 197 40.6 4.85×10

3

197 42.2 4.67×103

56

197 40.4 4.88×103

4.9×103 20.51 0.42 199 40.6 4.90×10

3

201 40.8 4.92×103

G25S

28

200 42.0 4.76×103

4.7×103 103.95 2.18 197 40.2 4.9×10

3

197 42.4 4.65×103

56

200 40.2 4.97×103

4.97×103 0.00 0.00 200 40.2 4.97×10

3

200 40.2 4.97×103

PH

28

198 42.6 4.65×103

4.7×103 28.81 0.61 200 42.4 4.72×10

3

200 42.6 4.7×103

56

199 42.2 4.71×103

4.73×103 11.17 0.24 200 42.2 4.74×10

3

200 42.2 4.74×103

PH25S

28

210 42.6 4.93×103

4.76×103 117.17 2.46 198 42.2 4.69×10

3

199 42.6 4.67×103

56

201 42.4 4.74×103

4.71×103 19.26 0.41 200 42.4 4.72×10

3

199 42.4 4.69×103

Page 128: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

115

Table D.8: Mass Measurements for Density (Phase III)

MIX

ID

Curing

Age

(Day)

Section

Density (CSA A23.2-11C)

Diameter

Average

(mm)

Volume

(mm3)

Average

Oven

Dry Mass

A

(Kg)

Average

Submerged

Mass

B

(Kg)

Average

Boiled

Mass

C

(Kg)

Average

Suspended

Mass

D

(Kg)

GU

28

1

102.23 8.2×105 1.83 1.92 1.92 1.09

2

3

4

56

1

102.23 8.2×105 1.81 1.90 1.90 1.08

2

3

4

GU25S

28

1

101.85 8.14×105 1.86 1.94 1.94 1.11

2

3

4

56

1

102.24 8.2×105 1.84 1.92 1.92 1.10

2

3

4

PH

28

1

102.16 8.2×105 1.84 1.92 1.92 1.10

2

3

4

56

1

102.03 8.17×105 1.82 1.91 1.91 1.10

2

3

4

PH25S

28

1

102.53 8.25×105 1.88 1.94 1.94 1.11

2

3

4

56

1

101.52 8.09×105 1.84 1.91 1.92 1.11

2

3

4

Page 129: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

116

Table D.9: Absorption and Density (Phase III)

MIX

ID

Curing

Age

(Day)

absorption

after

immersion,

%

absorption

after

immersion

and boiling,

%

Dry Density

(Oven-dried),

Kg/m3

Density after

immersion,

Kg/m3

Density after

immersion

and boiling,

Kg/m3

GU 28 5.00 4.71 2220.3 2331.4 2325

56 5.22 5.16 2210.2 2325.5 2324.3

GU25S 28 4.09 3.98 2248.9 2340.9 2338.5

56 4.35 4.35 2232.9 2330.0 2330.1

PH 28 4.26 4.33 2244.6 2340.4 2341.9

56 4.81 5.03 2228.4 2335.6 2340.6

PH25S 28 3.28 3.39 2256.8 2330.9 2333.4

56 3.80 4.37 2254.9 2340.7 2353.4

Table D.10: Rapid Chloride Permeability (Phase III)

MIX

ID

Curing

Age

(Day)

Section

RCPT (ASTM C 1202)

Average

Diameter

(mm)

Total

Charge

Passed

Average

Adjusted

Charge

Passed

Average St.Dev Co.V.

(%)

GU

28 1

102.18 5013

4396.5 4349

3814 535 14.03 2 3780 3279

56 1

101.91 3312

2761.0 2873

2414 459 19.01 2 2210 1955

GU25S

28 1

102.3 1690

1609.0 1466

1395 70 5.05 2 1528 1325

56 1

101.92 1165

1138.5 1011

997 13 1.35 2 1112 984

PH

28

1

101.93

5210

3959.7

4519

3434 895 23.63 2 3146 2729

3 3523 3056

56 1

102.57 4009

4244.5 3618

3714 96 2.60 2 4480 3811

PH25S

28 1

102.26 1643

1707.0 1425

1480 55 3.75 2 1771 1536

56 1

102.01 924

953.0 802

835 33 4.01 2 982 869

Page 130: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

117

Table D.11: Initial Sorptivity – GU and GU+25%GGBFS at 28d (Phase III)

Initial

Sorptivity GU (28d) GU25S (28d)

Surface FINISHED FORMED FINISHED FORMED

Section 1 2 3 1 2 3 1 2 3 1 2 3

x10(-

4)mm/sec

1/2

14.98 17.95 15.85 5.02 6.79 5.82 5.65 27.41 40.07 28.01 24.22 4.18

Average 16.26 5.88 33.74 26.11

ST.Dev 1.53 0.89 8.95 2.68

Co.V. (%) 0.09 0.15 0.27 0.10

Table D.12: Initial Sorptivity – GU and GU+25%GGBFS at 56d (Phase III)

Initial

Sorptivity GU (56d) GU25S (56d)

Surface FINISHED FORMED FINISHED FORMED

Section 1 2 3 1 2 3 1 2 3 1 2 3

x10(-

4)mm/sec

1/2

17.38 23.72 12.33 5.65 6.30 6.38 7.09 17.31 22.18 14.98 6.29 14.98

Average 17.81 6.11 19.75 14.98

ST.Dev 5.70 0.40 3.45 0.00

Co.V. (%) 0.32 0.07 0.17 0.00

Table D.13: Initial Sorptivity – PH and PH+25%GGBFS at 28d (Phase III)

Initial

Sorptivity PH (28d) PH25S (28d)

Surface FINISHED FORMED FINISHED FORMED

Section 1 2 3 1 2 3 1 2 3 1 2 3

x10(-

4)mm/sec

1/2

17.28 11.57 18.59 13.15 9.53 8.35 19.35 24.80 12.56 16.09 10.76 9.22

Average 15.81 10.34 18.91 12.03

ST.Dev 3.73 2.50 6.13 3.60

Co.V. (%) 0.24 0.24 0.32 0.30

Page 131: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

118

Table D.14: Initial Sorptivity – PH and PH+25%GGBFS at 56d (Phase III)

Initial

Sorptivity PH (56d) PH25S (56d)

Surface FINISHED FORMED FINISHED FORMED

Section 1 2 3 1 2 3 1 2 3 1 2 3

x10(-

4)mm/sec

1/2

13.44 13.17 14.03 11.05 13.07 9.63 16.01 23.23 15.96 9.64 14.49 14.98

Average 13.55 11.25 18.40 13.04

ST.Dev 0.44 1.73 4.18 2.95

Co.V. (%) 0.03 0.15 0.23 0.23

Table D.15: Salt-Scaling Mass Loss (Phase III)

Avg. Mass/Area

(Kg/m2)

Mix ID GU G25S PH PH25S

Surface Finished Formed Finished Formed Finished Formed Finished Formed

# C

ycl

es

5 0.055 0.016 0.179 0.034 0.899 0.032 1.184 0.080

10 0.085 0.024 0.249 0.053 1.492 0.101 1.815 0.314

15 0.099 0.032 0.276 0.065 1.739 0.131 2.021 0.379

20 0.110 0.044 0.291 0.071 1.851 0.149 2.116 0.421

25 0.121 0.049 0.302 0.077 1.895 0.185 2.198 0.451

30 0.136 0.054 0.309 0.083 1.928 0.224 2.291 0.477

35 0.147 0.059 0.316 0.090 1.962 0.265 2.396 0.529

40 0.165 0.068 0.319 0.101 1.984 0.293 2.483 0.560

45 0.173 0.075 0.326 0.115 2.008 0.324 2.569 0.583

50 0.183 0.082 0.333 0.135 2.039 0.394 2.695 0.635

Page 132: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

119

Table D.16: ASTM C666 Freeze-Thaw Data (Phase III)

Prism # #1 #2

MIX ID Cycles

Frequency

Hz

Relative

Dynamic

Modulus

of

elasticity

(%)

Length

change

(%)

Durability

Factor

(%)

Frequency

Hz

Relative

Dynamic

Modulus

of

elasticity

(%)

Length

change

(%)

Durability

Factor

(%)

GU

0 3319

3374

36 3271 97.13 0.01 97.13 3333 97.58 0.00 97.58

76 3274 97.31 0.01 97.31 3326 97.17 0.01 97.17

112 3271 97.13 -0.02 97.13 3339 97.94 0.01 97.94

141 3267 96.89 0.02 96.89 3336 97.76 0.02 97.76

187 3266 96.83 0.03 96.83 3325 97.12 0.03 97.12

229 3266 96.83 0.03 96.83 3323 97.00 0.02 97.00

262 3193 92.55 0.02 92.55 3317 96.65 0.02 96.65

300 3180 91.80 0.04 91.80 3304 95.89 0.03 95.89

GU25S

0 3417

3434

36 3368 97.15 0.00 97.15 3362 95.85 0.00 95.85

76 3358 96.58 0.00 96.58 3389 97.40 0.16 97.40

112 3362 96.81 0.01 96.81 3382 96.99 0.00 96.99

141 3350 96.12 0.01 96.12 3370 96.31 0.02 96.31

187 3341 95.60 0.02 95.60 3370 96.31 0.02 96.31

229 3339 95.49 0.02 95.49 3368 96.19 0.02 96.19

262 3338 95.43 0.02 95.43 3363 95.91 0.01 95.91

300 3331 95.03 0.03 95.03 3357 95.57 0.02 95.57

PH

0 3281

3154

36 3278 99.82 0.01 99.82 3143 99.30 -2.12 99.30

76 3218 96.20 0.01 96.20 3136 98.86 0.01 98.86

112 3222 96.44 0.01 96.44 3136 98.86 0.01 98.86

141 3214 95.96 0.04 95.96 3130 98.48 -0.02 98.48

187 3186 94.29 0.02 94.29 3123 98.04 0.02 98.04

229 3182 94.06 0.02 94.06 3122 97.98 0.01 97.98

262 3175 93.64 0.02 93.64 3120 97.86 0.01 97.86

300 3168 93.23 0.03 93.23 3114 97.48 0.02 97.48

PH25S

0 3276

3353

36 3219 96.55 0.01 96.55 3294 96.51 0.00 96.51

76 3216 96.37 0.02 96.37 3283 95.87 0.00 95.87

112 3227 97.03 0.01 97.03 3304 97.10 0.01 97.10

141 3196 95.18 0.01 95.18 3293 96.45 0.01 96.45

187 3173 93.81 0.03 93.81 3256 94.30 0.01 94.30

229 3188 94.70 0.03 94.70 3243 93.55 0.01 93.55

262 3144 92.10 0.02 92.10 3240 93.37 0.01 93.37

300 3137 91.69 0.03 91.69 3235 93.09 0.02 93.09

Page 133: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

120

D.3 Phase IV

Table D.15: Compressive Strength (Phase IV)

MIX

ID

Curing

Age

(Day)

Compressive Strength (CSA.A23.2-9C)

Strength

Reading

(KN)

Strength

Reading

(Mpa)

Average

(MPa) St.Dev.

Co.V.

(%)

GU

28

361.2 44.2

45 0.65 1.45 366.9 44.9

374.2 45.8

PH

276.4 33.8

34.7 0.95 2.72 279.7 34.3

294.4 36.0

Table D.16: Ultra Pulse Velocity (Phase IV)

MIX

ID

Curing

Age

(Day)

UPV (ASTM C 597)

Length

(mm)

UPV

Reading

(µSec)

Pulse

Velocity

(m/s)

Average

Pulse

Velocity

(m/s)

St.Dev. Co.V.

(%)

GU

28

197 40.2 4.9×103

4.8×103 82.1 1.70 198 40.6 4.9×10

3

199 42.2 4.7×103

PH

195 44.2 4.4×103

4.5×103 46.8 1.05 200 44.2 4.5×10

3

200 44.6 4.5×103

Table D.17: Rapid Chloride Permeability (Phase IV)

MIX

ID

Curing

Age

(Day)

Section

RCPT (ASTM C 1202)

Average

Diameter

(mm)

Total

Charge

Passed

Average

Adjusted

Charge

Passed

Average St.Dev Co.V.

(%)

GU

28

1 102.22

3398 3188.5

2948 2766 182 6.58

2 2979 2584

PH 1

101.98 6444

5926.5 5590

5187 402 7.76 2 5409 4785

Page 134: Properties and Performance of Photocatalytic Concrete...concrete in mechanical and fluid transport properties. Although photocatalytic concrete resisted rapid freeze and thaw damage

121

Table D.18: Salt-Scaling Mass Loss (Phase IV)

Avg. Mass/Area

(Kg/m2)

Mix ID GU PH

Surface Finished Formed Finished Formed

# C

ycl

es

5 0.860 0.014 1.119 0.014

10 0.934 0.050 1.849 0.030

15 0.961 0.068 2.126 0.043

20 0.987 0.090 2.363 0.058

25 1.006 0.111 2.545 0.070

30 1.019 0.128 2.706 0.080

35 1.035 0.162 2.888 0.092

40 1.040 0.195 3.037 0.098

45 1.048 0.252 3.192 0.100

50 1.058 0.301 3.312 0.105