DETERMINATION OF MIXING AND COMPACTING TEMPERATURES FOR

HOT MIX ASPHALT

NOORAFIDAH BINTI ITHNIN

A project report submitted in partial fulfillment of the

requirement for the award of the degree of

Master of Engineering (Civil-Transportation and Highway)

Faculty of Civil Engineering

Universiti Teknologi Malaysia

NOVEMBER, 2008

iii

Dedicated to my beloved mother, Hjh. Satina Mat Alias,

My Husband, Miskam,

Dear sons, Haziq, Aiman and Erfan

Idah, Juli, Rostam and Firdaus

And Special Appreciation to

All lecturers of Transportation & Highway Department,

Lab colleagues Azah, Ros, Nhat & Hameed.

To Wadad, Ina, Kak Miha, Izudin, Nana, Dayah and all friends ..

Thanks for all the support.

iv

ACKNOWLEDGEMENT

In the name of Allah S.W.T, I would like to express my gratefulness and most heartfelt

thanks to Him for giving me strength to finish my project.

First and foremost, I wish to express my gratitude to my supervisor, Assoc. Prof. Dr. Mohd.

Rosli bin Hainin, for his guidance and constructive critics throughout the tough path in

completing this report. Thanks for continuously and patiently guided me throughout every

step of my thesis work and generously shared your time and knowledge with me.

Appreciation also goes to Mr. Suhaimi, Mr Abdul Rahman, Mr. Mohd. Adin, and Mr. Azman

of the Transportation and Highway Laboratory, UTM, for rendering their help, both time and

energy. A special word of thanks is also reserved for my laboratory colleagues for being there

to share knowledge and experience with me. Last, but not least, I would like to acknowledge

each and every person who have contributed to the success of this report, whether directly or

indirectly. May God bless you in your life journey.

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ABSTRACT

Malaysia has been using bitumen grade of 80-100 penetration for many years. The

typical mixing and compacting temperature has been normally set as 160°C and 140°C

respectively based on experience for the lab procedure purpose. With the newly revised

Specification of Roadwork 2007 by JKR, new bitumen grade had been introduced

including grade 60-70 and some other types of modified bitumen. The objective of this

study is to determine the appropriate mixing and compacting temperature for the bitumen

grades by viscosity and correlation with other physical properties of bitumen. Rotational

Brookfield Viscometer was used to determine the correct temperature for viscosity at

165°C and 135°C and at viscosity ranges of 0.17±0.02 and 0.28±0.03 Pa s for mixing and

compacting, respectively as per ASTM D 2493. The result shows that the PEN 60/70

bitumen, PG 76 and PG 82 show higher mixing and compacting temperature than PEN

80/100. It also indicates that penetration shows close relationship with viscosity and

could be used to determine the mixing and compacting temperatures.

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ABSTRAK

Bitumen gred PEN 80-100 telah digunakan di Malaysia semenjak dahulu lagi.

Suhu bancuhan dan pemadatan asphalt yang biasa digunakan masing-masing ialah 160°C

dan 140°C berdasarkan kepada pengalaman dan prosedur biasa di makmal. Dengan

pengenalan kepada Semakan Semula Spesifikasi Kerja Jalan 2007 oleh Jabatan Kerja

Raya Malaysia, beberapa jenis bitumen baru diperkenalkan termasuk PEN 60-70 dan

bitumen Terubahsuai. Objektif kepada kajian ini ialah untuk menentukan suhu bancuhan

dan pemadatan bagi beberapa jenis bitumen yang biasa digunakan di Malaysia serta

kajian ke atas kelikatan dan hubungkaitan dengan ciri-ciri fizikal bitumen.

Alat Rotational Brookfield Viscometer digunakan untuk menentukan suhu yang

sebenar berdasarkan kelikatan pada suhu 165°C dan 135°C dan pada sela kelikatan

0.17±0.02 untuk bancuhan dan 0.28±0.03 Pa s untuk pemadatan sebagaimana ASTM D

2493. Keputusan menunjukkan bahawa bitumen PEN 60/70, PG 76 dan PG 82

menunjukkan suhu bancuhan dan pemadatan yang lebih tinggi berbanding bitumen PEN

80/100. Kajian juga menunjukkan nilai Penusukan menunjukkan hubungkait yang rapat

dengan Kelikatan dan boleh digunakan untuk menentukan suhu bancuhan dan pemadatan

asfal.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION OF THE STATUS OF THESIS

SUPERVISOR’S DECLARATION

TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xiii

LIST OF ABBREVIATIONS/SYMBOLS xv

LIST OF APPENDICES xvi

1 INTRODUCTION

1.1 Research Background 1

1.2 Problem Statement 2

1.3 Aim and Objective of The Study 4

1.4 Scope of the Study 4

1.5 Significant of The Study 5

1.6 Limitation of the Study 5

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1.7 Outline of Project 5

2 LITERATURE REVIEW

2.1 Introduction 6

2.2 Nature of bitumen 7

2.2.1 Saturates 7

2.2.2 Aromatic 8

2.2.3 Resins 8

2.2.4 Asphaltenes 9

2.3 Type of Bitumen 10

2.3.1 Paving Grade Bitumen 10

2.3.2 Cutback Bitumen 10

2.3.3 Bitumen Emulsion 11

2.3.4 Industrial Bitumen 12

2.3.5 Modified Bitumen 12

2.4 Bitumen Grading System 13

2.4.1 Penetration Grading 13

2.4.2 Viscosity Grading 15

2.4.3 Superpave Performance Grading (PG) System 17

2.5 Rheological Properties of Bitumen 20

2.5.1 Rotational (or Brookfield) Viscometer (RV) 21

2.5.2 Penetration Test 22

2.5.3 Softening Point Test 24

2.6 Bitumen Modification 25

2.6.1 Criteria of Improvement 25

2.6.2 Generic of Classification 27

2.7 Viscosity 29

2.7.1 Absolute viscosity 29

2.7.2 Kinematic Viscosity 31

2.7.3 Newtonian and Non-Newtonian Fluids 31

2.7.4 Specific Gravity Effect 33

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2.7.5 Viscosity-Temperature Graph 33

2.7.6 Viscosity-Temperature Relationship for Asphalt 35

2.8 Penetration Index (PI) 38

3 METHODOLOGY

3.1 Introduction 40

3.2 Operational Framework 41

3.3 Consistency Tests 42

3.3.1 Viscosity Test

3.3.1.1 Introduction 42

3.3.1.2 Apparatus 43

3.3.1.3 Procedures 43

3.3.2 Penetration Test

3.3.2.1 Introduction 45

3.3.2.2 Apparatus 48

3.3.2.3 Procedures 49

3.3.3 Softening Point Test

3.3.3.1 Introduction 50

3.3.3.2 Apparatus 51

3.3.3.3 Procedures 51

4 RESULTS AND DISCUSSION

4.1 Introduction 54

4.2 Viscosity Test Results 55

4.3 Penetration Test Results 57

4.4 Softening Point Test and Penetration Index (PI) Results 58

4.5 Relationship Between Viscosity, Penetration, Softening Point

And Penetration Index (PI) 59

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5 CONCLUSIONS

5.1 Introduction 64

5.2 Conclusion 65

REFERENCE

APPENDICES

xi

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Prediction of PG Grades for Different Crude Oil Blends 20

2.2 Generic Classification of Asphalt Additive and Modifier 27

2.3 Summary of the Potential Benefits from using Binder

Modifiers in Mixtures 28

3.1 Values of penetration and the maximum discrepancy allowed 50

4.1 Viscosity Test results 55

4.2 Bitumen Properties From Viscosity-Temperature Chart 57

4.3 Result of Penetration of Bitumen 57

4.4 Result of Softening Point and Penetration Index 58

4.5 Minimum and Maximum Mixing and Compacting Temperature

Based on Penetration 60

xii

4.6 Minimum and Maximum Mixing and Compacting Temperature

From Viscosity Temperature Chart 60

xiii

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Typical Structures of Some of The Molecules

Found in Bitumen 9

2.2 Indication of Relative Size of Bitumen Particle 11

2.3 Comparison of Penetration and Viscosity Asphalt Grade 17

2.4 Rotational Viscometer 21

2.5 Rotational Viscometer Schematic 22

2.6 The Penetration Test 24

2.7 Softening Point 25

2.8 Effects of an Anti stripping Modifier 26

2.9 Rotary Viscometer ASTM 2983 30

2.10 Typical Equiviscosity Curve for Asphalt Binder 34

xiv

3.1 The operational framework for the tests and analysis 41

3.2 Thermosel and Viscometer 45

3.3 Penetration test for an asphalt binder sample 46

3.4 Water bath 46

3.5 Penetration Test Setup 48

3.6 Ring and Ball apparatus 53

3.7 Softening Point Test Setup 53

4.1 Bitumen viscosity vs temperature relationship for Various

Type of Bitumen Tested 56

4.2 Relationship between Minimum & Maximum Mixing/

Compacting Temperature versus Penetration@25oC 59

4.3 Relationship between Softening Point vs Penetration 61

4.4 Relationship between Viscosity and Penetration@25oC 62

4.5 Penetration Index(PI) versus Type of Bitumen 63

xv

LIST OF ABBREVIATIONS

ASTM American Society for Testing and Materials

JKR Jabatan Kerja Raya

SBS Styrene-butadiene-styrene

HMA Hot Mix Asphalt

RV Rotational Viscometer

AASHTO American Association of State Highway and Transportation Officials

PG Penetration Grade

PI Penetration Index

xvi

LIST OF APPENDICES

APPENDIX. TITLE PAGE

A Rotational Viscometer Temperature Test Result 70

B Penetration Test 75

C Softening Point Test 80

1

CHAPTER ONE

INTRODUCTION

1.1 Research Background

Bitumen is a thermoplastic material and its consistency changes with temperature.

According to Roberts et al, (1996), at 275oF (135

oC) the bitumen viscosity is very low.

This characteristic is not desirable as that could result in occasional tender mix problem

during compacting. Their viscosity (stiffness) at the lowest service temperature in the

other hand, are usually very high, resulting in low temperature shrinkage cracking.

In addition, Hunter (2000) noted that it is important to have knowledge of

bitumen viscosity at certain key point during the manufacture and lay of mixture,

particularly during aggregate coating and compacting of mixture because the physical

aspect of bitumen at low temperature is hard and has high viscosity. This resembles a

solid and brittle but at higher temperature it becomes liquid and low viscosity.

Currently in most countries around the world, bitumen are graded according to a

number of traditional, and often empirical tests. For example in UK, penetration and

softening point have long been the basis of the grading systems. Elsewhere, fundamental

properties such as viscosity have also been specified. Based on these properties, binder

supplier have built up experience of how different binder will comply with the

specification ( Claxton, 1996).

2

To date, a lot of changes on grades of bitumen used where new grades are

introduced to cater for specific needs in construction, unknown modifiers and heavy duty

mixes. However, the criteria which never change after decades of asphalt use is the

needs on understanding the viscosity for determination of mixing and compacting

temperature of bitumen.

ASTM D2493 Calculation of Mixing and Compaction temperatures was

established for unmodified bitumen binders, which are Newtonian fluids at high

temperatures as for unmodified binder, viscosity does not depend on shear rate.

Stuart, (2001) mentioned that standardized procedures for determining the mixing

and compaction temperature to be used in the laboratory are based on the equiviscous

principle, which was developed 30 to 40 years ago for unmodified asphalt binders. This

principle states that the allowable compaction temperature range is the range that

provides an asphalt binder viscosity from 250 to 310 mm2/s. There are methods for

determining appropriate laboratory mixing and compaction temperatures for mixtures

modified binders, but they require additional mixture tests to be performed during

mixture design. A methodology like the equiviscous principle greatly reduces the

amount of mixture testing that needs to be performed.

1.2 Problem Statement

Bitumen grade of 80-100 penetration has been widely used in Malaysia for many

years. It is important to have knowledge of bitumen viscosity during the manufacture

and lay of mixture, aggregate coating and compaction of mixture because in nature

bitumen is solid, brittle and high viscosity at low temperature, but becomes liquid and

low viscosity at higher temperature. The typical mixing and compaction temperature has

been normally set as 160°C and 140°C respectively base on experience during the lab

procedure.

3

With the vast development of construction industry in Malaysia, JKR has

introduced newly revised Specification of Roadwork 2007 which list new bitumen grade

including modified bitumen. According to the changes, it is necessary to choose accurate

typical mixing and compaction temperature as a lab procedure to ensure the effectiveness

and workability of the bitumen. This leads to the objective to determine the appropriate

mixing and compaction temperature for the bitumen grades.

Historically, standardized procedures for determining mixing and compaction

temperature should be used in the laboratory for mixture design have not provided valid

temperatures for many asphalt mixtures for neat and modified binder. The use of an

incorrect laboratory mixing and compaction temperature as a basis for adjusting the

temperature of a hot-mix asphalt plant has caused significant problems in the field.

Therefore, paving contractors generally use plant temperatures recommended by the

suppliers of modified binders

According to Stuart (2001), the advantage of determining the mixing temperature of

particular bitumen is to produce a good quality mixture at reasonable operating cost as

excessively high temperatures may damage the asphalt binder, generate fumes, cause

asphalt binder draindown, and may lead to a low asphalt binder content in some mixtures.

Compacting bitumen at too high a temperature also may result in hairline cracks and mix

displacement and if the bitumen is compacted at too low a temperature, there is a risk that

the bonds between the aggregate and the binder will break up, or that the aggregate will

be crushed.

Determining the compacting temperature will help to controls bitumen viscosity

which affects its ability to coat and provide adequate lubrication for aggregates to slides

with each other and pack into dense mass during compaction.

According to Lu (1997), for the base (neat) bitumen and modified bitumen

containing a low polymer content (3% by weight in his study), dynamic viscosity is

relatively independent of shear rate, indicating that these binders have a purely viscous

Newtonian flow. However the modification with a sufficiently high modifier (SBS)

increases the degree of non-Newtonian behaviour of bitumen.

4

1.3 Aim and Objective of The Study

The aim of the study is to establish a graphical relationship between temperature

and viscosity to increase accuracy for mixing and compacting temperature for neat and

modified bitumen and eliminate unnecessary wastage of power and change of bitumen

properties during construction stage.

The objective of this study is to determine the appropriate mixing and compaction

temperature for various bitumen grades used in Malaysia. This study will also establish

the relationship between the physical properties that is viscosity, penetration and

softening point related to the mixing and compacting temperature.

1.4 Scope of the Study

The scope of the study focused on five types of bitumen including neat bitumen

grade of 2 types of PEN 80-100 from various supplier, PEN 60-70 and two types of

modified bitumen; PG 76 and PG 82. All type of bitumen were tested for their

rheological properties, which viscosity by using Brookfield Rotational Viscometer,

penetration test by using Penetrometer and softening point by using Ring & Ball

Apparatus.

1.5 Significant of the Study

Based on the result obtained from this study, a more accurate temperature of the

mixing and compacting of mixture using various type of bitumen are proposed to

improve the performance of the bitumen.

5

1.6 Limitation of Study

The study covers the process which was done in the lab and using limited type of

bitumen based on availability as per suppliers’ specification. Therefore the data collected

based on the handling of bitumen, the quality, modifier used, pollutant and others if any.

The procedures conducted were based on the Standard Test Method for Viscosity

Determination of Unfilled Asphalt Using the Brookfield Thermosel Apparatus ASTM

D4402-87(reapproved 2000), Penetration Test ASTM D 5 and Softening Point ASTM D

36. The tests are conducted in Makmal Pengangkutan, Universiti Teknologi Malaysia,

Skudai, Johor.

1.7 Outline of Project

This project consists of five chapters. Chapter I presents the introduction of the

study. It covers the problem statement, objectives, scope, significant and limitation of

study. Chapter II describes the literature review of the project. It explains the general

review of the bitumen properties and the behavior. Chapter III describes the

methodology which was used to determine the mixing and compaction of variety of

bitumen. Chapter IV discusses the result of laboratory experiment on the bitumen.

Chapter V highlights the conclusion and recommendation on relationship between

temperature of mixing and compacting of various type of bitumen and other factors.

6

CHAPTER II

LITERATURE REVIEW

2.1 Introduction

ASTM defines asphalt as dark brown to black cementitious material in which the

predominating constituent are bitumen, which occur in nature or are obtained in

petroleum processing, composed principally of high molecular weight hydrocarbons, of

which bitumen, tars, pitches, and asphaltene are typical.

By the last two decades of the nineteenth century, considerable amounts of

asphalt from the Trinidad Lake deposit were used for road building in the United States

and elsewhere in the world (Roberts et al, 1996).

This bitumen, once free of water, was too "hard" to use in paving. In fact,

Trinidad Lake bitumen, when loaded into a ship’s holds for transport, would fuse to the

point that removal required chopping.

Typically, producers added flux, created from petroleum distillation, to Trinidad

Lake bitumen to soften it for use in early pavements. It appears that the earliest use of

bitumen binder in the U.S. was about 1874 for a project built in Washington, D.C. This

binder was a combination of Trinidad Lake bitumen and a flux distilled from crude oil.

These early bitumen binders were quite variable, making pavement mix and structural

design somewhat challenging.

7

By the 1880s, bitumen binders were regularly produced from crude oil in

California and by 1902 in Texas as well. In 1907, crude oil-based bitumen production

surpassed "natural" bitumen production. Today, bitumen for HMA pavements is

produced almost entirely from petroleum refining.

2.2 Nature of Bitumen

Bitumen is a complex mixture of components with various chemical structures

composed of hydrocarbon, oxygen, sulphur and nitrogen.

The most common model used to describe the structure of bitumenis Micellar

Model and to understand this model, the hydrocarbon and heteroatom are further

subdivided. This compound is classified as saturates, aromatics, resin or asphaltenes.

2.2.1 Saturates

These are straight and branched chain molecule consisting of carbon and

hydrogen only. They are termed saturates because they contain almost exclusively single

carbon-carbon or carbon-hydrogen bonds although there may be some aromatic and

naphtenic ring structures present.

Since they are composed of only carbon and hydrogen, the saturates are non-polar

and show no great affinity on each other. When extracted from bitumen, the saturates

8

appear as a viscous, white to straw colored liquid with a molecular weight in the range of

300-2000. The saturates constitute between 5% and 20% of the total bitumen structure.

Consequently the saturates contribute very little to the stiffness of bitumen. They

do, however play an important part in defining the overall properties.

2.2.2 Aromatics

These are low molecular weight compounds comprising ring and chain structures

and form the major part of the dispersing medium for the asphaltenes (Refer Figure 2.1).

Unsaturated ring structures predominate in the overall aromatic structure which can

contribute up to 65% of total bitumen structure. When purified, the aromatics appear as

viscous brown liquid with a molecular weight in the range of 300-2000.

2.2.3 Resins

The resin are highly polar, predominantly hydrocarbon molecule with

significantly higher concentration of heteroatom than the other species which are present

in bitumen. They have been found to contain both acidic and basic group which means

that possibilities exist for hydrogen bonding and strong inter-molecular and intra-

molecular attraction. When purified, the resins appear as black or dark brown solid or

semi solid with molecular weight in the range of 500-50,000.

9

Figure 2.1 : Typical Structures of Some of The Molecules Found

in Bitumen (Hunter, 2000)

2.2.4 Asphaltenes

Asphaltenes are arguably the species with the highest molecular weight within the

bitumen structure. They are generally described as being very polar molecule containing

a high concentration of aromatic ring structures (Refer Figure 2.1). When purified, the

asphaltenes appear as solid black with a gritty or brittle feel. Depending on the method

of purification and analysis, the asphaltenes have been found to have molecular weight

ranging between 600-300,000. The asphaltene content, which may range between 5% to

25% has an enormous effect on the overall properties of bitumen.

Bitumen with high asphaltenes content will have higher softening point, higher

viscosities and lower penetration than those with low asphaltenes content.

Typical structure of an asphaltene molecule The R group may be aromatic or naphthenic

Typical structure of an aromatic molecule The R group may be other carbon ring structures

10

2.3 Type of Bitumen

According to BP (2008), , there are five major types of petroleum bitumen

produced by the refining and manufacturing process:

2.3.1 Paving grade bitumen

This bitumen is refined and blended to meet road engineering and industrial

specifications that take into account different climatic conditions and as a product it is the

most widely used bitumen. It may also be considered as the parent bitumen from which

the other types, listed below, are produced.

2.3.2 Cutback bitumen

Cutback bitumen consist basically of bitumen that has been diluted in order to

make it more fluid for application, mainly in road making. Their fluidity depends on the

degree of hardness of the bitumen base and the proportion of diluent (or flux) to bitumen.

They are classified according to the time it takes them to become solid, as rapid curing

(RC), medium curing (MC) or slow curing (SC) cutbacks. The cutback varies according

to the flux, white spirit commonly being used for RC grades, kerosene for MC and diesel

for SC.

As Cutback bitumen set, the flux evaporates and currently the evaporation is

regarded as a potentially undesirable characteristic from the point of view of the

environment and health and safety. Therefore cutback bitumen are looked upon less

favorably than the more modern bitumen emulsions.

11

2.3.3 Bitumen emulsion

The basic bitumen has also been diluted in order to facilitate application. Hot

bitumen, water and emulsifier are processed in a high-speed colloid mill that disperses

the bitumen in the water in the form of globules that are normally in the 5-10 micrometer

size range but may be even smaller. The emulsifier produces a system in which fine

droplets of bitumen, of between 30% and 80% of the volume, are held in suspension. If

they separate in storage, the emulsion can easily be restored by agitation.

Bitumen emulsions have a low viscosity and can be workable at ambient

temperatures, which makes them ideal for use in road construction. This application

requires controlled breaking and setting. The emulsion must not break before it is laid on

the road surface but, once in place, it should break quickly so that the road can be in

service again without delay.

Figure 2.2 : Indication of Relative Size of Bitumen Particle (BP, 2008)

Particles of bitumen that are dispersed in water to make bitumen emulsions are

usually between 5 and 10 micrometer in size. This gives an indication of relative size of

the particles (Figure 2.2). The mechanical performance of bitumen emulsions can also be

tailored like that of other construction materials.

The development of bitumen emulsions is an area where technological progress is

still being made to meet engineering demands. The first emulsions were the anionic.

12

They are currently less favor than the cationic because the positively charged globules of

bitumen coat the aggregates more thoroughly and have greater adhesion. Use of cationic

emulsions is therefore increasing.

2.3.3 Industrial bitumen

They also called as oxidized bitumen, are made by blowing air through hot paving

grade bitumen. The result is a product that softens at a higher temperature than that at

which paving grade bitumen softens. It also has more rubberlike properties and its

viscosity is much less affected by changes in temperature than is the case with paving

grade bitumen.

2.3.4 Modified bitumen

They are formulated with additives to improve their service performance by

changing such properties as their durability, resistance to ageing, elasticity and/or

plasticity. As well as natural rubbers, polymers such as styrene butadiene styrene (SBS),

thermoplastic rubbers and ethylene vinyl acetate (EVA) are commonly used to modify

bitumen and some companies, including BP, have their own proprietary technology using

special polymers or polymer blends. This is an exciting development of growing

importance due to the ability of modem technology to satisfy the demands of the bitumen

market internationally.

For example, polymers that extend the range of temperatures at which bitumen is

worked will enable road builders to work effectively for more months of the year. A

modified bitumen that increases the extent to which a road 'bounces back' after being

subjected to heavy traffic, in terms of weight and volume, will contribute towards a

longer road life and lower maintenance costs.

13

2.4 Bitumen Grading System

Asphalt binders are typically categorized by one or more shorthand grading

systems according to their physical characteristics. These systems range from simple to

complex and represent an evolution in the ability to characterize asphalt binder.

2.4.1 Penetration Grading

The penetration grading system was developed in the early 1900s to characterize

the consistency of semi-solid asphalts. Penetration grading quantifies the following

asphalt concrete characteristics:

(i) Penetration depth of a 100 g needle 25° C (77° F)

(ii) Flash point temperature

(iii)Ductility at 25° C (77° F)

(iv) Solubility in trichloroethylene

(v) Thin-film oven test (accounts for the effects of short-term aging)

a. Retained penetration

b. Ductility at 25° C (77° F)

Penetration grading basic assumption is that the less viscous the asphalt, the

deeper the needle will penetrate. This penetration depth is empirically (albeit only

roughly) correlated with asphalt binder performance. Therefore, asphalt binders with

14

high penetration numbers called "soft" are used for cold climates while asphalt binders

with low penetration numbers called "hard" are used for warm climates. The advantages

and disadvantages of Penetration grading are as follows :

The advantages of Penetration Grading are :

(i) The test is done at 25° C (77° F), which is reasonably close to a typical pavement

average temperature.

(ii) May also provide a better correlation with low-temperature asphalt binder

properties than the viscosity test, which is performed at 60° C (140° F).

(iii) Temperature susceptibility (the change in asphalt binder rheology with

temperature) can be determined by conducting the test at temperatures other than

25° C (77° F).

(iv) The test is quick and inexpensive. Therefore, it can easily be used in the field.

The disadvantages of Penetration Grading are :

(i) The test is empirical and does not measure any fundamental engineering

parameter such as viscosity.

(ii) Shear rate is variable and high during the test. Since asphalt binders typically

behave as a non-Newtonian fluid at 25° C (77° F), this will affect test results.

(iii) Temperature susceptibility (the change of asphalt binder rheology with

temperature) cannot be determined by a single test at 25° C (77° F).

(iv) The test does not provide information with which to establish mixing and

compaction temperatures.

2.4.2 Viscosity Grading

15

In the early 1960s an improved asphalt grading system was developed that

incorporated a rational scientific viscosity test. This scientific test replaced the empirical

penetration test as the key asphalt binder characterization. Viscosity grading quantifies

the following asphalt binder characteristics:

(i) Viscosity at 60° C (140° F)

(ii) Viscosity at 135° C (275° F)

(iii)Penetration depth of a 100 g needle applied for 5 seconds at 25° C (77° F)

(iv) Flash point temperature

(v) Ductility at 25° C (77° F)

(vi) Solubility in trichloroethylene

(vii) Thin film Oven Test (accounts for the effects of short-term aging):

Viscosity grading can be done on original (as-supplied) asphalt binder samples

called AC grading or aged residue samples called AR grading. The AR viscosity test is

based on the viscosity of aged residue from the rolling thin film oven test. With AC

grading the asphalt binder is characterized by the properties it possesses before it

undergoes the HMA manufacturing process. The AR grading system is an attempt to

simulate asphalt binder properties after it undergoes a typical HMA manufacturing

process and thus it should be more representative of how asphalt binder behaves in HMA

it should be more representative of how asphalt binder behaves in HMA it should be

more representative of how asphalt binder behaves in HMA pavements. The advantages

and disadvantages of the viscosity grading system are as follows :

Advantages of Viscosity Grading (from Roberts et al., 1996) :

(i) Unlike penetration depth, viscosity is a fundamental engineering parameter.

(ii) Test temperatures correlate well with 25° C (77° F) – average pavement

temperature, 60° C (140° F) – high pavement temperature and 135° C (275° F) –

HMA mixing temperature.

16

(iii) Temperature susceptibility; means the change in asphalt binder rheology with

temperature can be somewhat determined because viscosity is measured at three

different temperatures (penetration only is measured at 25° C (77° F)).

(iv) Testing equipment and standards are widely available.

The Disadvantages of Viscosity Grading (from Roberts et al., 1996) :

(i) The principal grading (done at 25° C (77° F)) may not accurately reflect low-

temperature asphalt binder rheology.

(ii) When using the AC grading system, thin film oven test residue viscosities can

vary greatly with the same AC grade. Therefore, although asphalt binders are

of the same AC grade they may behave differently after construction.

(iii)The testing is more expensive and takes longer than the penetration test.

Viscosity is measured in poise (cm-g-s = dyne-second/cm2). The lower the number of

poises, the lower the viscosity and thus the more easily a substance flows. Thus, AC-5

(viscosity is 500 ± 100 poise at 60° C (140° F)) is less viscous than AC-40 (viscosity is

4000 ± 800 poise at 60° C (140° F)).

17

.

Figure 2.3 : Comparison of Penetration and Viscosity Asphalt Grade (Robert, 1996)

2.4.3 Superpave Performance Grading (PG) System

Although in common use throughout the U.S., the previous grading systems are

limited in their ability to fully characterize asphalt binder for use in HMA pavement.

Therefore, as part of the Superpave research effort new binder tests and specifications

were developed to more accurately and fully characterize asphalt binders for use in HMA

pavements. These tests and specifications are specifically designed to address HMA

pavement performance parameters such as rutting, fatigue cracking and thermal cracking.

Superpave performance grading (PG) is based on the idea that an HMA asphalt

binder’s properties should be related to the conditions under which it is used. For asphalt

binders, this involves expected climatic conditions as well as aging considerations. The

PG system uses a common battery of tests as the older penetration and viscosity grading

18

systems but specifies that a particular asphalt binder must pass these tests at specific

temperatures that are dependant upon the specific climatic conditions in the area of use.

As a result, a binder used in the Sonoran Desert of California/Arizona/Mexico

would have different properties than one used in the Alaskan tundra. This concept

follows the same logic of penetration or viscosity graded asphalt binders but the

relationships between asphalt binder properties and conditions of use are more complete

and more precise with the Superpave PG system. Information on how to select a PG

asphalt binder for a specific condition is contained in Module 5, Section 5,

Superpave Method.

The limitation of Penetration, AC and AR Grading Systems compared to

Superpave PG system and Superpave Testing and Specification Features (after Roberts et

al., 1996) are as follows :

i. Penetration and ductility tests are empirical and not directly related to HMA

pavement performance.- The physical properties measured are directly related to

field performance by engineering principles.

ii. Tests are conducted at one standard temperature without regard to the climate in

which the asphalt binder will be used - Test criteria remain constant, however, the

temperature at which the criteria must be met changes in consideration of the

binder grade selected for the prevalent climatic conditions.

iii. The range of pavement temperatures at any one site is not adequately covered. For

example, there is no test method for asphalt binder stiffness at low temperatures to

control thermal cracking. The entire range of pavement temperatures experienced

at a particular site is covered.

iv. Test methods only consider short-term asphalt binder aging (thin film oven test)

although long-term aging is a significant factor in fatigue cracking and low

temperature cracking - Three critical binder ages are simulated and tested:

v. Original asphalt binder prior to mixing with aggregate.

vi. Aged asphalt binder after HMA production and construction.

vii. Long-term aged binder.

19

viii. Asphalt binders can have significantly different characteristics within the same

grading category - Grading is more precise and there is less overlap between

grades - Tests and specifications are intended for asphalt binders to include both

modified and unmodified asphalt cements.

Asphalt binder tests for Superpave performance grading are as follows :

(i) Rolling thin film oven

(ii) Pressure aging vessel

(iii) Rotational viscometer

(iv) Dynamic shear rheometer

(v) Bending beam rheometer

(vi) Direct tension tester

Superpave performance grading is reported using two numbers – the first being

the average seven-day maximum pavement temperature (°C) and the second being the

minimum pavement design temperature likely to be experienced (°C). Thus, a PG 58-22

is intended for use where the average seven-day maximum pavement temperature is 58°C

and the expected minimum pavement temperature is -22°C. The numbers represent the

pavement temperatures and not air temperatures. As a general rule-of-thumb, PG binders

that differ in the high and low temperature specification by 90°C or more generally

require some sort of modification (see Table 2.1).

20

Table 2.1: Prediction of PG Grades for Different Crude Oil Blends (Asphalt, 2003)

.

2.5 Rheological Properties of Bitumen

Rheology is the study of deformation and flow of matter. Deformation and flow

of the asphalt binder in HMA is important in determining HMA pavement performance.

HMA pavements that deform and flow too much may be susceptible to rutting and

bleeding, while those that are too stiff may be susceptible to fatigue or thermal cracking.

HMA pavement deformation is closely related to asphalt binder rheology. Since the

rheological properties of asphalt binder vary with temperature, rheological

characterization involves two key considerations:

(i) To compare different asphalt binders, their rheological properties must be

measured at some common reference temperature.

(ii) To fully characterize an asphalt binder, its rheological properties must be

examined over the range of temperatures that it may encounter during its life.

21

2.5.1 Rotational (or Brookfield) Viscometer (RV)

The rotational viscometer (RV) (see Figures 2.4) is used in the Superpave system

to test high temperature viscosities (the test is conducted at 135° C (275° F)). The basic

RV test measures the torque required to maintain a constant rotational speed (20 RPM) of

a cylindrical spindle while submerged in an asphalt binder at a constant temperature (see

Figure 2.5). This torque is then converted to a viscosity and displayed automatically by

the RV.

Figure 2.4: Rotational Viscometer

22

Figure 2.5: Rotational Viscometer Schematic (Asphalt, 2003)

The RV high-temperature viscosity measurements are meant to simulate binder

workability at mixing and laydown temperatures. Since the goal is to ensure the asphalt

binder is sufficiently fluid for pumping and mixing, Superpave specifies a maximum RV

viscosity. The RV is more suitable than the capillary viscometer (used for kinematic

viscosity) for testing modified asphalt binders because some modified asphalt binders

(such as those containing crumb rubber particles) can clog the capillary viscometer and

cause faulty readings.

The standard rotational (or Brookfield) viscometer test is AASHTO TP 48 and

ASTM D 4402: Viscosity Determination of Asphalt Binder Using Rotational Viscometer.

2.5.2 Penetration Test

The penetration test, an empirical test measures the consistency of paving asphalt

binder which is defined as the distance travelled by the vertical needle into a sample of

23

asphalt binder measured in tenths of a millimeter (decimillimeter, dmm) under known

conditions of loading, time, and temperature.

In general, the penetration test involves higher stresses and shorter loading time

than do most viscosity tests. Therefore, attention must be given to stress levels or shear

rates, or both, to attain direct comparison of penetration and viscosity results. Penetration

at 77oF (25

oC) has been widely used in asphalt binder specifications because no simple

method of viscosity determination at 77oF (25

oC), or lower temperatures, is currently

available (Roberts et al, 1996).

The current penetration test, first published in 1959, describes the following basic

procedure. The standard penetration test is AASHTO T 49 and ASTM D 5: Penetration

of Bituminous Materials.

(i) Melt and cool the asphalt binder sample under controlled conditions.

(ii) Measure the penetration of a standard needle into the asphalt binder sample under

the following conditions:

a. Load = 100 grams

b. Temperature = 25° C (77° F)

c. Time = 5 seconds

The depth of penetration is measured in units of 0.1 mm and reported in

penetration units (e.g., if the needle penetrates 8 mm, the asphalt penetration number is

80). Penetration grading is based on the penetration test.

24

Figure 2.6: The Penetration Test

2.5.3 Softening Point

The softening point is defined as the temperature at which a bitumen sample can

no longer support the weight of a 3.5-g steel ball. Basically, two horizontal disks of

bitumen, cast in shouldered brass rings (see Figure 2.7), are heated at a controlled rate in

a liquid bath while each supports a steel ball. The softening point is reported as the mean

of the temperatures at which the two disks soften enough to allow each ball, enveloped in

bitumen, to fall a distance of 25 mm (1.0 inch) (AASHTO, 2000).

The standard softening point test follows AASHTO T 53 and ASTM D 36:

Softening Point of Bitumen (Ring-and-Ball Apparatus).

25

Figure 2.7: Softening Point

2.6 Bitumen Modification

Some asphalt cements require modification in order to meet specifications.

Asphalt cement modification has been practiced for over 50 years but has received added

attention in the past decade or so. There are numerous binder additives available on the

market today. The benefits of modified asphalt cement can only be realized by a

judicious selection of the modifier(s); not all modifiers are appropriate for all

applications.

2.6.1 Criteria of Improvement

In general, asphalt cement should be modified to achieve the following types of

improvements (Roberts et al., 1996):

26

(i) Lower stiffness (or viscosity) at the high temperatures associated with

construction.

This facilitates pumping of the liquid asphalt binder as well as mixing and

compaction of HMA.

(ii) Higher stiffness at high service temperatures.

This will reduce rutting and shoving.

(iii) Lower stiffness and faster relaxation properties at low service temperatures.

This will reduce thermal cracking.

(iv) Increased adhesion between the asphalt binder and the aggregate in the presence

of moisture.

This will reduce the likelihood of stripping. Figure 2.8 shows two aggregate

samples from the same source after they have been coated with asphalt binder.

The asphalt binder used with the sample on the left contain no anti-stripping

modifier, which resulted in almost no aggregate-asphalt binder adhesion. The

asphalt binder used with the sample on the right contains 0.5% (by weight of

asphalt binder) of an anti-stripping modifier, which results in good aggregate-

asphalt binder adhesion.

Figure 2.8: Effects of an Anti stripping Modifier

27

2.6.2 Generic of Classification

Generic classification of asphalt additive and modifier are as follows :

Table 2.2 :Generic Classification of Asphalt Additive and Modifier (Robert, 1996)

TYPE GENERIC EXAMPLE

Filler Mineral filler : crusher fine, lime, Portland Cement, fly ash

Carbon black

Extender Sulfur

Lignin

POLYMER

Rubber

Natural latex

Synthetic latex

Block copolymer

Reclaimed rubber

Natural rubber

Sthyrene-butadene (SBR)

Polychlorophene Latex

Styrene-butadene-styrene(SBS), styrene-isoprene-styrene(SIS)

Crumb rubber modifier

Plastic

Polyethylene/polypropylene

Ethylene Archrylate Copolymer

Ethyl-vinyl-acetate(EVA)

Polyvinyl chloride(PVC)

Ethylene propylene(EPDM)

Polyolefin

Combination Blend of polymer in 3 and 4

Fiber Natural : asbestos, rock wool

Man-made : Polypropylene, polyester, fiberglass, mineral, cellulose

Oxidant Manganese salt

Antioxidant Lead compound, carbon, calcium salt

Hydrocarbon Recycling and rejuvenating oils

Hard and natural asphalts

28

Antistripping agent Amines

Lime

Waste material

Roofing shingle

Recycled tires

Glass

Miscellaneous Silicon

Deicing calcium chloride granules

Table 2.3 : Summary of the Potential Benefits from using Binder Modifiers

in Mixtures (HD 37/99 ,1999)

29

Notes

1. Where permanent deformation is improved the mixture may be designed to have

higher binder content, with the benefit of increased resistance to fatigue, thermal

cracking, ageing and moisture damage.

2. Within the same generic group there is a wide range of modifier composition and

performance benefit. The general distinctions between Plastomers and Elastomers are

becoming less well defined as innovation proceeds.

3. This table should be used as an overview and not for selection of a modifier for a

specific purpose.

2.7 Viscosity

According to HD 37/99 Design Manual for Roads and Bridges Volume 7 (1999),

binders are visco-elastic materials ; means they display both viscous and elastic

behaviour. A viscous material, like all liquids, continues to flow all the time a stress is

imposed on the material, as an elastic material deforms instantaneously under an applied

load and does not undergo further deformation thereafter. When the stress is removed, a

purely elastic material regains its original shape whereas a viscous material does not

recover but remains in the deformed state. Conventional binders are predominantly

elastic and brittle at low temperatures and viscous fluids at high road temperatures

depending on the frequency of loading.

2.7.1 Absolute Viscosity

Absolute viscosity is measured as the resistance to flow when an external and

controlled force (pump, pressurized air, etc.) forces oil through a capillary (ASTM

30

D4624), or a body is forced through the fluid by an external and controlled force such as

a spindle driven by a motor. In either case, the resistance to flow (or shear) as a function

of the input force is measured, which reflects the internal resistance of the sample to the

applied force, or its dynamic viscosity.

There are several types and embodiments of absolute viscometers. The Brookfield

rotary method pictured in Figure 2.9 is the most common. Absolute viscosity

measurement has historically been used for research applications, quality control and

grease analysis within the field of machinery lubrication.

Figure 2.9 : Rotary Viscometer ASTM 2983

Procedures for testing absolute viscosity in the lab by the traditional Brookfield

method are defined by ASTM D2983, D6080 and others. However, absolute viscosity is

becoming increasingly common in the area of used oil analysis because most onsite

viscometers sold on the market today measure absolute viscosity, not kinematic viscosity.

31

2.7.2 Kinematic Viscosity

In general, kinematic viscosity (cSt) is related to absolute viscosity (cP) as a

function of the fluid’s specific gravity (SG) according to the equations belows :

cSt = cP / SG

Or the equation’s inverse :

cP = cSt x SG

The above equations hold true only for so-called Newtonian fluids. In addition,

the specific gravity of the fluid must remain constant during the trending period. Neither

of these conditions can be assumed constant in used oil analysis, so the analyst must be

aware of the conditions under which variance can occur.

2.7.3 Newtonian and Non-Newtonian Fluids

Troyer (2002) expressed that a Newtonian fluid can be described as a fluid that

maintains constant viscosity across all shear rates (shear stress varies linearly with shear

rate). These fluids are called Newtonian because they follow the original formula

established by Sir Isaac Newton in his Law of Fluid Mechanics.

According to Jones (1987), the interactions between asphalt molecules are weak,

and the bonds may be broken through the action of heat or shear forces. This concept of

weak interactions between the molecules explains why asphalt behaves as a Newtonian

fluid at elevated temperatures, and also explains why asphalt exhibits constantly changing

behavior. Due to the weak nature of the polar-polar bonds, the bonds are constantly being

broken and reformed, each time in a unique way that never yields quite the same

material.

32

Some fluids, however, don’t behave this way. In general, they are called non-

Newtonian fluids. A group of non-Newtonian fluids referred to as thixotropic because the

viscosity of a thixotropic fluid decreases as the shear rate increases. The viscosity of a

thixotropic fluid increases as shear rate decreases. With thixotropic fluids, set-time can

increase apparent viscosity as in the case of grease.

The viscosity of a Non-Newtonian fluid could not be measured conventionally but

by measuring the apparent viscosity, which takes into consideration the shear rate at

which the viscosity measurement was made. Much like viscosity measurements do not

make sense unless the test temperature is reported, apparent viscosity measurements

don’t make sense unless the test temperature and the shear rate are reported. For example,

the viscosity of grease is never reported, rather the grease’s apparent viscosity is reported

in centipoises (cP).

A fluid is non-Newtonian if it is comprised of one substance suspended (but not

chemically dissolved) in a host fluid. There are two basic categories, emulsions and

colloidal suspensions. An emulsion is the stable physical coexistence of two immiscible

fluids.

A colloidal suspension is comprised of solid particles stably suspended in a host

fluid. For example, many paints are colloidal suspension. If the paint was Newtonian it

would either spread easily but run if the viscosity is low, or spread with great difficulty

and leave brush marks, but not run if the viscosity is high. Because the paint is non-

Newtonian, its viscosity yields under the force of the brush, but returns when the brush is

taken away. As a result, paint spreads with relative ease, but doesn’t leave brush marks

and doesn’t run.

To measure the absolute viscosity of one of these commonly encountered

emulsions or colloids described above with a variable shear rate absolute viscometer (for

example, ASTM D4741), the measurement would decrease as the shear rate increases, up

to a point of stabilization. If one were to divide this stabilized absolute viscosity by the

33

specific gravity of the fluid to estimate the kinematic viscosity, the calculated value

would differ from the measured kinematic viscosity.

2.7.4 Specific Gravity Effect

Referring to equation under 2.7.2, the absolute and kinematic viscosities of a

Newtonian fluid are related as a function of the fluid’s specific gravity. Most

hydrocarbon-based lubricating oils typically have a specific gravity of 0.85 to 0.90.

However, this can change over time as they becomes contaminated by water or dirt which

produces a differential between absolute and kinematic viscosity measurements.

2.7.5 Viscosity-temperature Graph

According to Roberts, et al., (1996), asphalt binders must remain sufficiently

fluid, or workable, at the high temperatures necessary during the plant mixing, field

placement and compaction of hot mix asphalt and the binder reaches temperatures

exceeding 135 oC during these procedures. The rotational viscometer (RV) is used to

evaluate binder in an unconditioned or neat state. This represents the state of material in

the tank at the asphalt plant. Measuring the rheological properties of asphalt binders

enable to evaluate their pumpability during delivery and plant operations.

The rotational viscometer is used to establish equiviscous temperature ranges for

selecting HMA mixing and compaction temperatures (Asphalt Institute, 2001). Mixing

and compaction temperatures are determined from viscosity-temperature graphs. A

typical log-log viscosity vs. log temperature graph is shown in Figure 2.10 (Asphalt

34

Institute, 2003). Viscosities at two temperatures are plotted on the log-log viscosity vs.

log temperature graph. The equiviscous temperature range for mixing and compaction

correspond to where the plotted line passes through the respective viscosity range.

Unlike the capillary viscometers used with the viscosity-graded method, the

rotational viscometer can also evaluate modified asphalt binders (Anderson, et al., 1994).

The viscosity of asphalt binders can be measured within the range of 0.01 Pa·s (0.1 poise)

to 200 Pa·s (2000 poise) (Petersen, et al., 1994).

Figure 2.10 Typical Equiviscosity Curve for Asphalt Binder

35

2.7.6 Viscosity-temperature Relationship For Asphalt

Rotational viscosity tests at two temperatures are needed when creating viscosity-

temperature graphs for establishing equiviscous temperature ranges. The lower

temperature measurement is taken first as it is much quicker to raise the temperature in

the thermo-chamber than to cool the sample for the second viscosity measurement. The

Asphalt Institute recommends taking the first viscosity measurement at 135 oC, and the

second at 165 oC (Asphalt Institute, 2001). A test temperature of 135

oC is specified for

evaluating pumpability in AASHTO MP1. Thus, prior to conducting tests for equiviscous

temperature ranges, the thermo-chamber should be preheated at the lower temperature.

Likewise, the sample holder and spindle are preheated in an oven heated to the lower

temperature.

A container of neat asphalt is placed in the oven and heated until fluid to pour.

The heated asphalt is poured into the sample holder to a level that will just cover the

upper conical portion of the spindle when it is lowered into the sample holder. The

sample holder is placed in the preheated thermo-chamber. The spindle is removed from

the oven, attached to the viscometer, and lowered into the asphalt sample. The system is

allowed to equilibrate for 30 minutes and the test is initiated.

Three viscosity measurements are taken at each test temperature. Thus, when

evaluating asphalt pumpability, three viscosity measurements are taken at 135 oC. When

establishing equiviscous temperature ranges, three measurements are taken at the lower

temperature and at the higher temperature.

If the displayed torque is out of the allowable viscosity range for the selected

spindle and operating speed, the spindle or speed is changed, as per the manufacturer’s

recommendations, and the test is restarted with a new asphalt specimen. The test is

terminated at the conclusion of the viscosity readings. The sample holder is removed

from the thermo-chamber and the asphalt specimen is discarded.

36

The test method requires the verification of the RV temperature controller. An

asphalt sample is placed in the testing chamber and heated to the test temperature. The

indicated temperature of the sample is verified via an ASTM thermometer. In addition to

the temperature controller verification, the accuracy of the rotational transducer is

checked by performing a viscosity test on a standard viscosity reference fluid.

Most asphalt binders behave like Newtonian fluids when heated to temperatures

exceeding 100 oC (Bahia and Anderson, 1995). A Newtonian fluid is characterized by a

totally viscous response, in which the viscosity is independent of the rate of shear strain.

Since asphalt has a totally viscous response at high temperatures, it is sufficient to

characterize the workability of the asphalt during mixing and construction with a measure

of its viscosity.

The working equations relating shear stress to torque and shear rate to angular

velocity are as follows (Petersen, et al., 1994 and Whorlow, 1992):

37

The unit of viscosity may be converted to pascal-seconds (Pa·s) using the

conversion :

1 centipoise = 0.001 Pa·s.

AASHTO MP1 requires a maximum viscosity limit of 3 Pa·s when tested at 135

oC. The maximum limit ensures that the asphalt binder is sufficiently fluid for pumping

during delivery and plant operations.

New mixing and compaction viscosity specifications were not developed during

the SHRP research (Asphalt Institute, 2001). The industry standard for the past twenty

years has been the viscosity ranges of 170±20 centistokes for mixing temperatures and

280±30 centistokes for compaction temperatures. The same viscosity ranges are still

recommended for Superpave; however, the units have been converted the Pascal-second

metric equivalent for Superpave Level 1 Mix Design (SP-2); 0.17 ± 0.02 Pa·s for mixing

and 0.28 ± 0.02 Pa·s for compaction.

38

2.8 Penetration Index (PI)

A parameter known as penetration index (PI) is often used to describe the

relationship between penetration and softening point (European Standard EN 12591

(1999) Bitumen and Bituminous Binders-Specifications for paving grade bitumen, Annex

B).

Since an asphalt has approximately a penetration of 800 at the softening point

temperature, the softening point temperature can be used along with the penetration at 25

°C to determine the temperature susceptibility as:

[ log(pen at 25 °C) - log(800)]

M = -----------------------------------------

(25 – Softening point temperature)

The M computed in this manner can then be used to compute a Penetration Index (PI) as

follows:

PI = (20 - 500 M) / (1 + 50 M) (45.5)

PI provides an indication of how the hardness of a bitumen changes with

temperature, i. e. its temperature susceptibility. For PI value which is less than -2 shows

that the bitumen has very strong bond to particle; that is Newtonian characteristic. A

higher PI with values higher than +2, denotes a lower temperature susceptibility and non

Newtonian characteristic. Bitumen for roads typically have PI values in the range-1 to +1

while bitumen for roofs typically have PI values of +3 to +7. Although roofing bitumen

have high PIs they are generally unsuitable for roads due to their very high viscosity at

asphalt mixing and laying temperatures (typically 100°C -180°C) which reduces the

workability and ease of compaction of the hot asphalt mix at the road construction stage.

39

High PI bitumen also tend to be slightly rubbery i. e. have elastic characteristics,

which can often mean that minor cracks in a pavement, induced by heavy traffic, may not

self-heal, which can be the case with normal road bitumen of lower PI. Also, high PI

bitumen are more susceptible to oxidative hardening due to their chemical nature.

40

CHAPTER III

METHODOLOGY

3.1 Introduction

This chapter discusses several tests that were conducted in achieving the

objectives of the study. The tests were carried out according to the required specification.

A total of 45 samples from 5 different types of asphalt binders for each type and each test

were prepared, namely PEN 80-100(Supp.A), PEN 80-100(Supp.B), PEN 60-70, PG 76,

and PG 82.

For the purpose of this study, all tests on the asphalt binders were conducted in

Makmal Pengangkutan, Universiti Teknologi Malaysia, Skudai. From the tests, the

rheological properties of the asphalt binders were determined.

41

3.2 Operational Framework

The operational framework for this study was summarized in the Figure 3.1

below:

Collecting asphalt binders

Preparing asphalt binders samples

Viscosity Test

Penetration Test

Softening Point Test

Data Analysis

Conclusion

Figure 3.1: The operational framework for the tests and analysis

42

3.3 Consistency Tests

Consistency describes the degree of fluidity of asphalt binder at any particular

temperature. Since asphalt binder is a thermoplastic material, its consistency varies with

the temperature. Therefore, it is necessary to measure the consistency of different asphalt

binders at the same temperature and shear loading conditions if comparisons are to be

made. The following consistency tests are performed on asphalt binders:

3.3.1 Viscosity Test

3.3.1.1 Introduction

The Brookfield Thermosel Viscometer is used to measure the viscosity of asphalt

at elevated temperatures. The rotational viscometer (RV) has been adopted in this study

for determining the viscosity of asphalt binder at high construction temperatures (above

100oC) to ensure that the binder is sufficiently fluid for pumping and mixing. The RV is

more suited for testing many modified asphalt binders compared to capillary viscometer

because the latter can get clogged up partially inhibiting smooth flow.

This method of measuring viscosity is given in detail in ASTM Method D4402,

“Viscosity Determination of Unfilled Asphalts Using the Brookfield Thermosel

Apparatus.” Rotational viscosity is determined by measuring the torque required to

maintain a constant rotational speed (20 RPM) of a cylindrical spindle while submerged

in an asphalt binder at a constant temperature. The measured torque is directly related to

the viscosity of the binder sample, which is automatically calculated and displayed by the

viscometer. Most asphalt binders can be tested with only two spindles: Nos. 21 and 27

where the latter is most frequently used.

43

The viscometer reading is displayed digitally along with spindle number, RPM,

and temperature. The digital display of the rotational viscosity is in units of centipoises

(cP) whereas the Superpave binder specification uses Pa.s. The following factor is used to

convert from cP to Pa.s.

1000 cP = 1 Pa.s

Therefore, the Brookfield viscosity output in cP is multiplied by 0.001 to obtain

viscosity in Pa.s.

3.3.1.2 Apparatus

(i) Brookfield Thermosel High Temperature Viscosity Measurement System Using a

Standard Brookfield Viscometer – Depending on viscosity range Model LV, RV,

HA, or HB series may be used.

(ii) Spindle size 27 for Brookfield Thermosel Viscometer.

(iii) Thermosel System:

a. Thermo Container and Sample Chamber.

b. SCR Controller and Probe.

3.3.1.3 Procedures

(i) Thermosel power is turned on.

(ii) The proportional temperature controller is set to desired temperature.

(iii) Wait 1.5 hour (or until equilibrium temperature is obtained) with the

selected spindle in the chamber (check control lamp).

44

(iv) The sample holder is removed and the volume of sample specified for the

spindle to be used is added. Caution is taken to avoid sample overheating

and to avoid ignition of sample with low flash point. The mass required

from specific gravity or density data for the sample is calculated.

Approximately 8 to 10 mL will be required.

(v) The sample volume is critical to meet the system calibration standard. The

filled asphalt coatings are thoroughly stirred to obtain a representative

sample.

(vi) The liquid level should intersect the spindle shaft at a point approximately

3.2 mm (1/8 in.) above the upper “conical body” – “spindle shaft”

interface.

(vii) Using the extracting tool, the loaded chamber back is put into the thermo

container.

(viii) The viscometer is lowered and the thermo-container is aligned.

(ix) The selected spindle is inserted into the liquid in the chamber, and coupled

to the viscometer.

(x) The asphalt is allowed to come to the equilibrium temperature.

(xi) The Brookfield viscometer is started at 20 rpm.

(xii) The speed (rpm setting) is maintained during the viscosity measurement.

45

Figure 3.2 : Thermosel and Viscometer

3.3.2 Penetration Test

3.3.2.1 Introduction

The penetration test is an empirical test used to measure the consistency of asphalt

binder. Usually penetration is measure at 77oF (25

oC) which also approximates average

service temperature of the HMA pavements in United States. At this temperature no

simple test method is currently available to measure the consistency of the asphalt binder

in terms of viscosity, although viscosity is the preferred form of measurement. The

standard penetration test is shown in figure below.

46

Figure 3.3 : Penetration test for an asphalt binder sample

Figure 3.4 : Water bath

47

The penetration test is run in accordance with ASTM D5. The test can also be run

at other temperatures such as 32oF (0

oC), 39.2

oF (4

oC), and 115

oF (46

oC). However, the

needle load or penetration time or both are then varied. At low temperatures, such as 4oC,

the asphalt binder is very stiff and therefore penetration of the needle is significantly

lower if it is loaded with a 100 g weight and is allowed to penetrate for 5 seconds. At

these temperatures, a 200 g weight and 60 seconds penetration time have been used to

obtain penetration values.

The penetration of a bituminous material may be defined as determining the

hardness or softness of bitumen by measuring the depth in tenths of a millimeter that a

standard needle vertically penetrates a sample of the material under known conditions of

loading, time and temperature. The penetration test is used for evaluating the consistency

of a bituminous material. The grade of semisolid and solid bituminous material is usually

designated by the penetration.

The penetrometer consists of a needle assembly with a total weight of 100g and a

device for releasing and locking in any position. The bitumen is softened to a pouring

consistency, stirred thoroughly and poured into containers at a depth at least 15 mm in

excess of the expected penetration. The test should be conducted at a specified

temperature of 25o C. It may be noted that penetration value is largely influenced by any

inaccuracy with regards to pouring temperature, size of the needle, weight placed on the

needle and the test temperature.

A grade of 40/50 bitumen means the penetration value is in the range 40 to 50 at

standard test conditions. In hot climates, a lower penetration grade is preferred. The

Figure 3.5 shows a schematic Penetration Test setup.

48

Figure 3.5: Penetration Test Setup

3.3.2.2 Apparatus

(i) Penetration apparatus – consist of needle assembly with total loads of 100g, an

apparatus capable of indicating the depth of penetration to the nearest 0.1 mm,

and an automated timing device accurate to within ± 0.1 second.

(ii) Sample container – made of metal or glass with flat bottom.

(iii) Transfer dish for container – a cylinder with flat bottom and a minimum inside

diameter of 90 mm.

(iv) Water bath – having capacity of at least 10 liters and capable of maintaining a

temperature varying not more than ± 0.1oC from the temperature of the test.

(v) Thermometer – conform to the requirements prescribed in ASTM or IP Standard

Thermometers.

49

3.3.2.3 Procedures

(i) The sample is heated with care, stirred as soon as possible to prevent local

overheating, until it has become sufficiently fluid to pour. Incorporating

bubbles are avoided in the sample.

(ii) The sample is poured into the sample container to a depth such that, when

cooled to the temperature of test, the depth of the sample is at least 10 mm

greater than the depth to which the needle is expected to penetrate.

(iii)Each container is loosely covered as a protection against dust and allowed to

cool in the atmosphere at a temperature between 15oC and 30

oC for 1 to 1 ½

hour.

(iv) The needle holder and guide are examined to establish the absence of water

and other extraneous matter.

(v) A penetration needle is cleaned with toluene or other suitable solvent, dried

with a clean cloth and the needle is inserted in the penetrometer.

(vi) The needle is positioned by slowly lowering it until its tip just makes contact

with the surface of the sample.

(vii) The reading of the penetrometer dial is noted and the pointer is brought to

zero.

(viii) The needle holder is quickly released for the specified period of time and

the instrument is adjusted to measure the distance penetrated in tenths of a

millimetre.

(ix) At least three determinations at points on the surface of the sample not less

than 10 mm from the side of the container and not less than 10 mm apart are

made. The needle is cleaned before repeating the test.

(x) The average of three penetrations is reported to the nearest whole unit whose

values do not differ by more than the amounts in the following table:

50

Table 3.1 : Values of penetration and the maximum discrepancy allowed

Penetration 0 to 49 50 to 149 150 to 249 250 and

above

Maximum difference

between highest and lowest

determination

2 4 6 8

(xi) The test is repeated using the second sample if the differences are exceeded.

(xii) The test is repeated completely and the results are ignored if the

appropriate tolerance is again exceeded.

3.3.3 Softening Point Test

3.3.3.1 Introduction

Softening point is measured by ring and ball (R & B) method in accordance with

ASTM D36. It can simply be defined as the temperature at which an asphalt binder

cannot support the weight of a steel ball and starts flowing. Its purpose is to determine the

temperature at which a phase change occurs in the asphalt binder.

Softening point is the temperature at which a substance attains a particular degree

of softness under specified conditions of test. As temperature increases, asphalt binder

changes from solid to liquid, and the stiffness of asphalt binder will reduce accordingly.

Before mixing with aggregates to form a road pavement, asphalt binder must be soft

enough in order for it to be handled easily during pavement work. The most common

method to soften the asphalt binder is by heating it. Higher grade asphalt binder has

51

higher softening temperature compare to lower grade asphalt binder. The ring and ball

test is commonly used to determine the softening temperature of asphalt binder.

3.3.3.2 Apparatus

(i) Steel ball having a diameter of 9.53 mm and weighing 3.50 ± 0.05 g.

(ii) Ring – square shouldered brass ring.

(iii) Ball guide – a convenient form of ball centering guide.

(iv) Ring holder made of brass or other metal.

(v) Bottom plate made of brass or other metal.

(vi) Thermometer.

(i) Bath – a heat resistant glass capable of supporting the rings in horizontal

position.

(ii) Bath liquid – distilled water or glycerol.

(iii) Mechanical Stirrer – to ensure uniform heat throughout the bath.

3.3.3.3 Procedures

(vii) The sample is heated with care, stirred as soon as possible to prevent local

overheating, until it has become sufficiently fluid to pour. Incorporating

bubbles are avoided in the sample.

(viii) The two rings are heated approximately to the same temperature as the

sample and placed on the metal plate, and without delay, the ring is filled

with the sample to give an excess above the top of the ring when cooled.

(ix) The ring is allowed to cool at room temperature, and then any excess

sample is removed with warm blade so that the test specimens are levelled

with the top of the rings.

52

(x) The thermometer is inserted through the hole in the top plate and adjusted

so that the bottom of the thermometer bulb will be level with the bottom of

the rings, i.e. just below (0.4 mm) the bottom of the ring holder.

(xi) The filled rings are placed in the ring holder and the ball-centering guides

are placed on the rings.

(xii) With the distilled water in the bath 5 ± 2oC, the assemble apparatus and

the steel balls are transferred to the bath.

(xiii) The level of the water is ensured to be 50 ± 5 mm above the tops of the

rings.

(xiv) The bath temperature is maintained at 5 ± 2oC for 15 minutes, then using

tongs or other suitable implement, a steel ball is placed on each of the test

specimens.

(xv) For each test specimen, the temperature shown by the thermometer is

estimated to the nearest half division at the instant that the asphalt binder

surrounding the ball touches the base plate. The temperature is recorded.

(xvi) If the differences between the two recorded temperatures exceed 1oC, the

test is repeated.

(xvii) The mean of the two recorded softening points is calculated and rounded

to the nearest 0.5oC.

53

Figure 3.6 : Ring and Ball apparatus

Figure 3.7: Softening Point Test Setup

54

CHAPTER IV

RESULTS AND DISCUSSION

4.1 Introduction

This chapter includes the analysis of all the results and discussions of the results

obtained from the analysis. The data analysis is divided into two parts; determining the

asphalt viscosity to derive the mixing and compacting temperature of HMA, and

comparing the data of all tests done to determine the relationship between the physical

characteristic studied.

Consistency tests were run to determine the penetration values, viscosity values

and the softening points of the five different type of asphalt samples. The data obtained

from viscosity test were used to establish equiviscous temperature ranges for selecting

HMA mixing and compaction temperatures. Mixing and compaction temperatures are

determined from a typical log-log viscosity vs. log temperature graphs.

The viscosity, penetration, softening point test data and penetration index

calculated were analyzed to see the relationship between the consistency tests and their

effect to the mixing and compacting temperatures of HMA.

55

4.2 Viscosity Test Results

Based on viscosity test, data collected are as follows :

Table 4.1 : Viscosity Test results

Average Viscosity (Pa.s) Temperature

(oC)

PEN 80/100

(supp A)

PEN 80/100

(supp B)

PEN 60/70 PG 76 PG 82

120 0.70 0.83 1.07 4.17 6.27

135 0.27 0.40 0.60 2.07 2.77

150 0.07 0.17 0.30 1.00 1.33

165 - 0.07 0.17 0.60 0.73

180 - 0.04 0.03 0.20 0.53

The data above are plotted on Standard Viscosity –Temperature Chart for Asphalt

ASTM D2493 as Figure 4.1.

The range for mixing and compacting based on viscosity are derived from

intersection of best fit line that falls within established viscosity recommended by

Asphalt Institute’s Superpave Level 1 Mix Design (SP-2) ranging from 0.17±0.02 and

0.28±0.03 Pa.s respectively.

56

Figure 4.1 : Bitumen viscosity vs temperature relationship

for Various Type of Bitumen Tested

From Figure 4.1, PEN 80/100 (Supplier A) shows the lowest mixing and

compacting temperature followed by PEN 60/70, PG 76 and PG 82. The R2 value for

each line is more than 0.9 show close relationship between viscosity and temperature of

bitumen.

Based on Figure 4.1 the viscosity at 135 oC and 165

oC and the range of mixing

and compacting temperature for each type of bitumen are derived as per Table 4.2 below.

57

Table 4.2 Bitumen Properties From Viscosity-Temperature Chart

Viscosity@

135oC

Viscosity@

165oC

Mixing

temperature

Compacting

temperature

Properties

Type of

Bitumen Pa s Pa s oC

oC

PEN 80/100

(Supplier A) 0.24 - 138-141 131-134

PEN 80/100

(Supplier B) 0.38 - 148-153 139-143

PEN 60/70 0.58 0.11 155-159 146-150

PG 76 2.10 0.49 184-189 174-179

PG 82 3.00 0.84 199-205 188-193

4.3 PenetrationTest Results

Based on penetration test, data collected are as follows :

Table 4.3 Result of Penetration of Bitumen

Average

Penetration@ 25oC

Properties

Type of Bitumen (dmm)

PEN 80/100

(Supplier A) 89.20

PEN 80/100

(Supplier B) 84.08

PEN 60/70 63.50

PG 76 61.20

PG 82 37.8

58

Bitumen PEN 80/100 and PEN 60/70 has higher penetration values compared to

the modified bitumen, PG76 and PG82. Higher penetration value means softer bitumen.

4.4 Softening Point Test and Penetration Index (PI) Results

Table 4.4 Result of Softening Point and Penetration Index

Softening Point Penetration

Index

Properties

Type of Bitumen oC

PEN 80/100

(Supplier A) 38.38 -3.43

PEN 80/100

(Supplier B) 38.75 -3.42

PEN 60/70 49.30 -0.81

PG 76 59.30 1.41

PG 82 69.00 1.98

Table 4.4 above shows the results obtained from the Softening point tests and

Penetration Index calculated from the Penetration and Softening Point data. From this

Table, for any PEN and PG graded bitumen tested, Softening Point Test, the Ring & Ball

Test results shows that tor any PEN and PG graded bitumen tested, softening point

generally low for unmodified bitumen and higher for modified bitumen. Based on the

figure, the Penetration Index shows negative value for unmodified bitumen and positive

value for modified bitumen.

59

4.5 Relationship Between Viscosity, Penetration, Softening Point and

Penetration Index (PI)

The relationship between the physical properties studied; viscosity, penetration

and softening point and calculated Penetration Index (PI) related to the mixing and

compacting temperature is analyzed. Figures below are based on Table 4.2, 4.3 and 4.4

shows the correlation between physical properties studied.

Figure 4.2 : Relationship between Minimum & Maximum Mixing/Compacting Temperature versus Penetration@25

oC

Figure 4.2 presents the relationship between Minimum & Maximum Mixing/

Compacting Temperature versus Penetration@25oC. Acceptable models are obtained

based on the linear model employed on the test data. The high value of R2 that is 0.86

indicates that a linear model exactly represents the relationship between Minimum &

Maximum Mixing/Compacting Temperature versus Penetration@25oC. This indicates

60

that the besides of viscosity, penetration is also able to show the required temperature for

mixing and compacting by the model shown. Based on Figure 4.2, the minimum and

maximum mixing and compacting temperature based on the penetration are as Table 4.5.

Table 4.5 Minimum and Maximum Mixing and Compacting Temperature Based on Penetration

Type of bitumen

Minimum

Mixing

Temperature

Maximum

Mixing

Temperature

Minimum

Compacting

Temperature

Maximum

Compacting

Temperature

PEN 80/100

(Supp.A) 138.95 142.6 131.14 134.52

PEN 80/100

(Supp.B) 144.94 148.81 136.81 140.36

PEN 60/70

169.04 173.77 159.57 163.85

PG 76

171.73 176.56 162.11 166.47

PG 82

199.14 204.95 187.99 193.17

The minimum and maximum mixing and compacting temperature From

Viscosity-Temperature Chart ( Figure 4.1), are as Table 4.6.

Table 4.6 Minimum and Maximum Mixing and Compacting Temperature From Viscosity-Temperature Chart

Type of bitumen

Minimum

Mixing

Temperature

Maximum

Mixing

Temperature

Minimum

Compacting

Temperature

Maximum

Compacting

Temperature

PEN 80/100

(Supp.A) 138 141 131 134

PEN 80/100

(Supp.B) 148 153 139 143

PEN 60/70

155 159 146 150

PG 76

184 189 174 179

PG 82

199 205 188 194

61

The belows Figure 4.3 represents the relationship between Softening Point versus

Penetration. Acceptable models are obtained based on the linear model employed on the

test data. The high value of R2 of 0.94 indicates that a linear model exactly represents the

relationship between Softening Point versus Penetration. As the penetration increases the

softening point decreases.

Figure 4.3 : Relationship between Softening Point vs Penetration

62

Figure 4.4 : Relationship between Viscosity and Penetration@25oC

Figure 4.4 shows a good the relationship between Viscosity at 135oC & 165

oC

and Penetration with the high value of R2 (0.82 and 0.857). Penetration basic assumption

is that the less viscous the asphalt, the deeper the needle will penetrate and the

penetration depth is empirically correlated with asphalt binder performance. As

penetration is easily and commonly used compared to viscosity instrument which is much

expensive, viscosity of asphalt binders could be predicted by penetration value.

63

Figure 4.5: Penetration Index(PI) versus Type of Bitumen

Figure 4.5 shows the results obtained from PI calculated for each type of bitumen.

For any PEN and PG graded bitumen tested, Penetration Index is generally negative

value for highly temperature susceptibility bitumen and positive value for low

temperature susceptibility bitumen.

64

CHAPTER V

CONCLUSIONS

5.1 Introduction

The aim of the study is to establish a graphical relationship between temperature

and viscosity to increase accuracy for mixing and compacting temperature for neat and

modified bitumen and eliminate unnecessary wastage of power and change of bitumen

properties during construction stage. To achieve this, the physical properties of bitumen

that related to temperature that is viscosity, penetration, softening point and penetration

index are studied. As viscosity is the most related to temperature, this study is done to

determine the appropriate mixing and compaction temperature for various bitumen grades

used in Malaysia based on temperatures of 135°C and 165°C and established the line

through these two points falls within established viscosity ranges of 0.17±0.02 and

0.28±0.03 Pa s for mixing and compaction, respectively according to Superpave

recommended evaluation test.

This study also establish the relationship between the physical properties that is

viscosity, penetration and softening point related to the mixing and compacting

temperature.

65

5.2 Conclusion

From the test on relationship of the viscosity and temperature, the range of mixing

and compacting temperature for most common types of bitumen were determined. From

the result, PG 76 and PG 82 have higher mixing and compacting temperature compared

with typical unmodified bitumen. For PG 82, the range of mixing temperature are 199-

205 o C and compacting temperature are 188-193

o C and PG 76, the range of mixing

temperature are 184-189 o C and compacting temperature are 174-179

o C. Whereas

60/70 PEN, the range of mixing temperature are 155-159 o

C and compacting

temperature are 146-150 o C and 80/100 PEN (Supplier A and B), the range of mixing

temperature are 148-153 o

C, compacting temperature are 139-143 o

C and mixing

temperature are 138-141 o

C, compacting temperature are 131-134 o C respectively.

Because of their distinctive characteristic, modified bitumen frequently mixed and

compacted at higher temperature than unmodified binder.

Besides of viscosity, other properties like penetration and softening point also

have close relationship with the mixing and compacting temperature through the

relationship and R2 value shown. The models to predict the temperature for mixing and

compacting through penetration could be used based on R2 of more than 0.8.

Relationship between Minimum & Maximum Mixing/Compacting Temperature

versus Penetration@25oC will help to predict the required temperature of mixing and

compacting.

The minimum and maximum mixing and compacting temperature derived based

on penetration test value are as important as viscosity based since the penetration test is

much easier, faster and cheaper and most often used compared to viscosity.

66

The relationship between Softening Point versus Penetration shows that high

penetration bitumen has a low softening point. High penetration means the bitumen are

soft therefore the required temperature at which bitumen becomes soft enough to flow is

also low.

Regarding to the relationship between Viscosity@135oC and viscosity@165

oC

with Penetration@25oC, as penetration is easier, faster and cheaper compared to

viscosity, by measuring the penetration, user could predict the correct Viscosity@135oC

(for compacting) and viscosity@165oC (for mixing). For satisfactory coating and mixing

of aggregate, approximate viscosity of bitumen should be 0.2 Pa.s. During compaction, if

the viscosity is too low, the mix is excessively mobile and too high viscosity will reduce

workability. The optimal viscosity recommended is between 2 and 20 Pa.s.

The penetration Index (PI) for five type bitumen studied shows value from -3.43

to +1.98. This PI value can be used to give a good approximation of the bitumen

behavior expected but confirmation by testing on stiffness and viscosity measurement is

necessary as extreme extrapolation could be misleading. The bitumen PI value that more

than +1 and less than -1 shows the bitumen tested is not suitable for road construction.

67

REFERENCES

3.3 Materials – Asphalt (2003) website. Viewed on January 2008,

<http://training.ce.washington.edu/wsdot/modules/03_materials/03-3_body.htm>

American Society for Testing and Materials. Standard Viscosity-Temperature Chart

for Asphalts ASTM D2493.

American Society for Testing and Materials (1997). Standard test method for

penetration of bituminous materials, ASTM D5, Philadelphia.

American Association of State Highway Official Viscosity Determination of Asphalt

Binder Using Rotational Viscometer AASHTO TP48 .

Asphalt Institute (1990). “Introduction to Asphalt.” Lexington, Kentucky, United

States of America: Asphalt Institute, Research Park Drive.

Asphalt Institute (1990). “Laboratory Mixing and Compaction Temperature.”

Lexington, Kentucky, United States of America: Asphalt Institute, Research Park

Drive.

Bahia, H. U., Hanson, D. I., Zeng, M., H., Khatri, M. A., and Anderson, R. M.

(2001), Characterization of Modified Asphalt Binders in Superpave Mix Design”

National Cooperative Highway Research Program, Rep. No. NCHRP 459, National

Acedemy Press, Washington D.C

68

BP(2008) website. Viewed on Februari 2008

<http://www.bp.com/liveassets/bp_internet/bitumen/.../downloads_pdfs/s/sources.pdf>

Claxton & Green, P.J, (1997), The Classification of Bitumens and Polymer Modified

Bitumens Within the SHRP Performance Grading System, BP Oil International,UK.

Hunter, R.N. (2000). Asphalt In Road Construction. Thomas Telford Limited,

London.

Hunter, R.N. (2003). The Shell Bitumen Handbook Fifth Edition., Thomas Telford

Limited, London.

James, H. Banks, Introduction to Transportation Engineering, Houbslow Books,

London, Mdx, UK.

Jabatan Kerja Raya (JKR) (2005). Standard Specifications for Road Works. Kuala

Lumpur, Malaysia, JKR/SPJ/rev2005.

Lee, M. G., Chiu, C. T., Kan., Y. C., Chen., K. C., Comparison of Results of SHRP

and Conventional Binder Tests on Paving Asphalts, International Journal of Applied

Science and Engineering, 2004. 245-256.

Roberts, L.F., Kandhal, P.S., Brown, R.E., Lee, D.Y., Kennedy, T.W. (1996). Hot

Mix Asphalt Materials, Mixture, Design and Construction. NAPA Education

Foundation. Maryland.

Stuart, Kevin. D., (2002), Methodology of Determining Compaction Temperature for

Modified Asphalt Binder, Federal Highway Administration, U.S Department of

Transportation, Virginia.

69

Yetkin, Y. P. E. (2006). Evaluation of Viscosity Values For Mixing and Compacting

Temperature. Journal of Materials In Civil Engineering@ASCE July/August 2006.

545-553.

1

APPENDICES A - C

70

APPENDIX A

ROTATIONAL VISCOMETER TEMPERATURE TEST RESULT

Type of bitumen : PEN 80/100 Supplier A

Spindle size : 27 / 33g in weight

Test

Temperature

Torque Shear

Rate

Viscosity Viscosity Average

Viscosity

(oC) (%) (sec

-1) (cP) (Pa.s) (Pa.s)

120 0.70 6.80 700.00 0.70

120 0.70 6.80 700.00 0.70 0.70

120 0.70 6.80 700.00 0.70

135 0.30 6.80 300.00 0.30

135 0.30 6.80 300.00 0.30 0.27

135 0.30 6.80 300.00 0.20

150 0.10 6.80 100.00 0.10

150 0.00 6.80 0.00 0.00 0.07

150 0.10 6.80 100.00 0.10

165 0.00 6.80 0.00 0.00

165 0.00 6.80 0.00 0.00 0.00

165 0.00 6.80 0.00 0.00

180 0.00 6.80 0.00 0.00

180 0.00 6.80 0.00 0.00 0.00

180 0.00 6.80 0.00 0.00

71

ROTATIONAL VISCOMETER TEMPERATURE TEST RESULT

Type of bitumen : PEN 80/100 Supplier B

Spindle size : 27 / 33g in weight

Test

Temperature

Torque Shear

Rate

Viscosity Viscosity Viscosity

(oC) (%) (sec

-1) (cP) (Pa.s) (Pa.s)

120 0.6 6.8 600 0.6

120 0.9 6.8 900 0.9 0.83

120 1.0 6.8 1000 1.0

135 0.3 6.8 300 0.3

135 0.4 6.8 400 0.4 0.40

135 0.5 6.8 500 0.5

150 0.1 6.8 100 0.1

150 0.1 6.8 100 0.1 0.17

150 0.3 6.8 300 0.3

165 0.0 6.8 0 0.0

165 0.0 6.8 0 0.0 0.07

165 0.2 6.8 200 0.2

180 0.0 6.8 0 0.0

180 0.0 6.8 0 0.0 0.03

180 0.1 6.8 100 0.1

72

ROTATIONAL VISCOMETER TEMPERATURE TEST RESULT

Type of bitumen : PEN 60/70

Spindle size : 27 / 33g in weight

Test

Temperature

Torque Shear

Rate

Viscosity Viscosity Viscosity

(oC) (%) (sec

-1) (cP) (Pa.s) (Pa.s)

120 1.0 6.8 1000 1.0

120 1.0 6.8 1000 1.0 1.07

120 1.2 6.8 1200 1.2

135 0.5 6.8 500 0.5

135 0.4 6.8 400 0.4 0.60

135 0.9 6.8 900 0.9

150 0.3 6.8 300 0.3

150 0.2 6.8 200 0.2 0.30

150 0.4 6.8 4000 0.4

165 0.2 6.8 200 0.2

165 0.1 6.8 100 0.1 0.17

165 0.2 6.8 200 0.2

180 0.1 6.8 100 0.1

180 0.0 6.8 0 0.0 0.03

180 0.0 6.8 0 0.0

73

ROTATIONAL VISCOMETER TEMPERATURE TEST RESULT

Type of bitumen : PG 76

Spindle size : 27 / 33g in weight

Test

Temperature

Torque Shear

Rate

Viscosity Viscosity Viscosity

(oC) (%) (sec

-1) (cP) (Pa.s) (Pa.s)

120 4.2 6.8 4200 4.2

120 4.0 6.8 4000 4.0 4.17

120 4.3 6.8 4300 4.3

135 2.1 6.8 2100 2.1

135 2.1 6.8 2100 2.1 2.07

135 2.0 6.8 2000 2.0

150 1.3 6.8 1300 1.3

150 0.8 6.8 800 0.8 1.00

150 0.9 6.8 900 0.9

165 0.6 6.8 600 0.6

165 0.6 6.8 600 0.6 0.60

165 0.6 6.8 600 0.6

180 0.2 6.8 0 0.0

180 0.4 6.8 400 0.4 0.20

180 0.2 6.8 200 0.2

74

ROTATIONAL VISCOMETER TEMPERATURE TEST RESULT

Type of bitumen : PG 82

Spindle size : 27 / 33g in weight

Test

Temperature

Torque Shear

Rate

Viscosity Viscosity Viscosity

(oC) (%) (sec

-1) (cP) (Pa.s) (Pa.s)

120 9.0 6.8 6800 6.8

120 6.4 6.8 6400 6.4 6.27

120 5.6 6.8 5100 5.6

135 3.7 6.8 3700 3.7

135 2.3 6.8 2300 2.3 2.77

135 2.3 6.8 2400 2.3

150 1.7 6.8 1700 1.7

150 1.1 6.8 1100 1.1 1.33

150 1.2 6.8 1300 1.2

165 1.0 6.8 1000 1.0

165 0.6 6.8 600 0.6 0.73

165 0.6 6.8 800 0.6

180 0.8 6.8 800 0.8

180 0.4 6.8 400 0.4 0.53

180 0.4 6.8 600 0.4

75

APPENDIX B

PENETRATION TEST

Type of Bitumen PEN 80/100 (Supplier A)

Temperature : 25oC

Load : 100 g

Time : 5

seconds

Cup 1

Test No. 1 2 3 4 5

Penetration 89 88.5 89.5 87 91

Average Penetration (dmm) 89.00

Cup 2

Test No. 1 2 3 4 5

Penetration 88.5 88.5 92 88 89.5

Average Penetration (dmm) 88.33

Cup 1

Test No. 1 2 3 4 5

Penetration 89.5 89 88 93 92.5

Average Penetration (dmm) 88.83

Cup 2

Test No. 1 2 3 4 5

Penetration 89.5 93.5 90 92.5 90

Average Penetration (dmm) 89.83

Cup 1

Test No. 1 2 3 4 5

Penetration 89.5 90.5 93.5 90.5 89

Average Penetration (dmm) 90.16

Cup 2

Test No. 1 2 3 4 5

Penetration 90.5 91 92 88.5 88.5

Average Penetration (dmm) 89.16

76

PENETRATION TEST

Type of Bitumen PEN 80/100 (Supplier B)

Temperature : 25oC

Load : 100 g

Time : 5

seconds

Cup 1

Test No. 1 2 3 4 5

Penetration 82 85 85 86 85

Average Penetration (dmm) 85.00

Cup 2

Test No. 1 2 3 4 5

Penetration 84.5 81 84 84 81

Average Penetration (dmm) 84.16

Cup 1

Test No. 1 2 3 4 5

Penetration 83 84.5 87.5 81 84.5

Average Penetration (dmm) 84.00

Cup 2

Test No. 1 2 3 4 5

Penetration 85.5 88.5 85 85 85.5

Average Penetration (dmm) 85.16

Cup 1

Test No. 1 2 3 4 5

Penetration 86 84 83 85 82.5

Average Penetration (dmm) 83.16

Cup 2

Test No. 1 2 3 4 5

Penetration 86.5 82 82.5 86 84.5

Average Penetration (dmm) 83.00

77

PENETRATION TEST

Type of Bitumen : PEN 60/70

Temperature : 25oC

Load : 100 g

Time : 5

seconds

Cup 1

Test No. 1 2 3 4 5

Penetration 63 64 65 62.5 62.5

Average Penetration (dmm) 62.67

Cup 2

Test No. 1 2 3 4 5

Penetration 62.5 62.5 64 62.5 63

Average Penetration (dmm) 62.50

Cup 1

Test No. 1 2 3 4 5

Penetration 64.5 63 64 61.5 65.5

Average Penetration 64.30

Cup 2

Test No. 1 2 3 4 5

Penetration 64.5 62.5 66 64 65.5

Average Penetration (dmm) 64.66

Cup 1

Test No. 1 2 3 4 5

Penetration 62.5 68.5 63 66.5 65

Average Penetration 63.50

Cup 2

Test No. 1 2 3 4 5

Penetration 63 65.5 64 63 67.5

Average Penetration (dmm) 63.33

78

PENETRATION TEST

Type of Bitumen : PG 76

Temperature : 25oC

Load : 100 g

Time : 5

seconds

Cup 1

Test No. 1 2 3 4 5

Penetration 63.5 66 65 61.5 61.5

Average Penetration (dmm) 62.17

Cup 2

Test No. 1 2 3 4 5

Penetration 62.5 63.5 66.5 63 62

Average Penetration (dmm) 62.50

Cup 1

Test No. 1 2 3 4 5

Penetration 61 61 62 61.5 63

Average Penetration (dmm) 61.16

Cup 2

Test No. 1 2 3 4 5

Penetration 60.5 64.5 65.5 60.5 61.5

Average Penetration (dmm) 60.83

Cup 1

Test No. 1 2 3 4 5

Penetration 61 58.5 61.5 59.5 58.5

Average Penetration (dmm) 60.66

Cup 2

Test No. 1 2 3 4 5

Penetration 58 59 58.5 60.5 60.5

Average Penetration (dmm) 60.00

79

PENETRATION TEST

Type of Bitumen : PG 82

Temperature : 25oC

Load : 100 g

Time : 5

seconds

Cup 1

Test No. 1 2 3 4 5

Penetration 37 38.5 36.5 38 38.5

Average Penetration (dmm) 38.33

Cup 2

Test No. 1 2 3 4 5

Penetration 38.5 39.5 39.5 37 38.5

Average Penetration (dmm) 38.83

Cup 1

Test No. 1 2 3 4 5

Penetration 39 38.5 45.5 38.5 40

Average Penetration (dmm) 38.66

Cup 2

Test No. 1 2 3 4 5

Penetration 39 37.5 39 39.5 40

Average Penetration (dmm) 39.16

Cup 1

Test No. 1 2 3 4 5

Penetration 35.5 35.5 37 36.5 36.5

Average Penetration (dmm) 36.16

Cup 2

Test No. 1 2 3 4 5

Penetration 32.5 35.5 36 36 35.5

Average Penetration (dmm) 35.66

80

APPENDIX C

SOFTENING POINT OF BITUMEN

Description of Material : PEN 80/100 (Supplier A)

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 37.00

2 37.50 37.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.00

2 38.00 38.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.00

2 39.00 38.50

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.50

2 39.00 38.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.50

2 38.50 38.50

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 39.00

2 39.50 39.25

81

SOFTENING POINT OF BITUMEN

Description of Material : PEN 80/100 (Supplier B)

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.50

2 39.50 39.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.00

2 38.00 38.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.50

2 39.00 38.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 38.00

2 38.50 38.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 39.00

2 39.00 39.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 39.00

2 40.00 39.50

82

SOFTENING POINT OF BITUMEN

Description of Material : PEN 60/70

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 48.00

2 48.50 48.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 50.00

2 50.50 50.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 49.00

2 49.50 49.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 50.00

2 50.00 50.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 48.50

2 49.00 48.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 49.00

2 50.00 49.50

83

SOFTENING POINT OF BITUMEN

Description of Material : PG 76

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 58.50

2 59.00 58.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 58.00

2 58.50 58.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 58.00

2 58.50 58.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 59.50

2 60.00 59.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 60.00

2 60.00 60.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 61.00

2 61.50 61.25

84

SOFTENING POINT OF BITUMEN

Description of Material : PG 82

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 68.50

2 69.50 69.00

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 68.50

2 69.00 68.75

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 69.00

2 69.50 69.25

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 69.00

2 70.00 69.50

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 68.00

2 69.00 68.50

Ring No. Instant Temperature, oC Softening Point, Average

oC

1 68.00

2 70.00 69.00