Major project final

CHAPTER 1

INTRODUCTION

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INTRODUCTION

Concrete is the most widely used construction material in the world. In recent years,

researchers have focused on the improvement of concrete quality regarding its mechanical

and durability properties. These can be achieved by the application of the supplementary

cementitious materials.

Out of these supplementary cementitious materials, silica fume is the one of the waste

materials that is being produced in tones of industrial waste per year in our country. The first

testing of silica fume in Portland-cement-based concretes was carried out in 1952. The

biggest drawback to exploring the properties of silica fume was a lack of material to

experiment with. Early research used an expensive additive called fumed silica, an

amorphous form of silica made by combustion of silicon tetrachloride in a hydrogen-oxygen

flame. Silica fume on the other hand, is a very fine pozzolanic material. It is a by-product of

producing silicon metal or ferrosilicon alloys. One of the most beneficial uses of silica fume

is in concrete. Because of its chemical and physical properties; it is a very reactive pozzolanic

material. Concrete containing silica fume has very high strength and is very durable.

The main field of application is as pozzolanic material for high performance concrete. Silica

fume is an ultrafine airborne material with spherical particles less than 1 µm in diameter, the

average being about 0.1 µm. This makes it approximately 100 times smaller than the average

cement particle. The unit weight, or bulk density, of silica fume depends on the metal from

which it is produced. Its unit weight usually varies from 130 to 430 kg/mᶾ. The specific

gravity of silica fume is generally in the range of 2.20 to 2.5. In order to measure the specific

surface area of silica fume a specialized test called the “BET method” or nitrogen adsorption

method must be used. Based on this test the specific surface of silica fume typically ranges

from 15,000 to 30,000 mᶾ/kg. Silica fume increase durability, toughness and it give very low

permeability to chloride and water intrusion in the concrete.

Silica fume is sold in powder form but is more commonly available in a liquid. Silica fume is

used in amounts between 5% and 15% by mass of the total cementitious material. It is used in

applications where a high degree of impermeability is needed and in high- strength concrete.

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CHAPTER-2

MATERIALS AND SPECIFICATIONS

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MATERIAL USED AND THEIR PROPERTIES

Concrete which is a homogenous Mixture of cement and fine aggregates derives its strength

in presence of water through hydration .The bonding strength of concrete mainly depends on

the cement used and the compressive strength of concrete is derived from coarse and fine

aggregates used.

In the experimental work following ingredients are used

2.1Cement:

Ultra tech cement of ordinary Portland cement (OPC) of 53 Grade was used which satisfies

the requirements of IS: 12269-1987.

S.N.O PROPERTIES RESULTS

1 Normal Consistency 29.50%

2 Specific Gravity 3.0

3 Initial setting time 33 min

2.2Aggregate:

Fine Aggregate: locally available sand was used. The sand was conforming to zone IV as per

IS: 383-1987. The properties of fine aggregate are shown in Table


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1 Bulk density (kg/m^3) 1650

2 Specific gravity 2.60

2.3Coarse Aggregate:

The crushed aggregate was used from the local quarry. In this experiment the aggregate was

used of 20mm down and tested as per IS: 2386-1963(I, II, III) specification. The properties of

coarse aggregate are shown in Table


1 Maximum Nominal size 20mm

2 Bulk density (kg/m^3) 1800

3 Specific gravity 2.67

2.4Silica Fume:

The silica fume was used in these experiments conforms to ASTM C 1240 and IS

15388:2003. The silica fume is extremely fine particle, which exists in white color powder

form.


1 Form Ultra fine amorphous powder

2 Colour White

3 Specifc gravity 2.39

4 Pack density 0.76 gm/cc

5 Specific surface 20m^2 /g

6 Particle size 15μm

7 Sio2 99.89%

2.5 Water:

Normal portable water obtained from Gandipet water reservoir was used for the experiment.

2.6 Super Plasticizers: CEMCRETE SP25 was used for M50 Grade of concrete. The

properties of super plasticizer is shown in table

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Colour Brown

Specific gravity 1.20+0.035

Chloride content Nil to BS 5075 to I.S:456-

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Nitrate content Nil

Freezing point 0°C

Air entrainment Maximum 0.5%

Dosage:

0.2 to 0.5% by weight of the cement depending upon the condition of the materials and

conditions. Trail mixes are recommended prior to production of concrete.

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CHAPTER-3

LITERATURE SURVEY

SILICA FUME

3.1 Introduction

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Silica fume, also referred to as micro silica or condensed silica fume, is a by-product material

that is used as a pozzolan. This by-product is a result of the reduction of high-purity quartz

with coal in an electric arc furnace in the manufacture of silicon or ferrosilicon alloy. Silica

fume rises as an oxidized vapour from the 2000°C (3630°F) furnaces. When it cools it

condenses and is collected in huge cloth bags. The condensed silica fume is then processed to

remove impurities and to control particle size.

Condensed silica fume is essentially silicon dioxide (usually more than 85%) in non

crystalline (amorphorous) form. Since it is an airborne material like fly ash, it has a spherical

shape. It is extremely fine with particles less than 1 µm in diameter and with an average

diameter of about 0.1 µm, about 100 times smaller than average cement particles.

Condensed silica fume has a surface area of about 20,000 m2/kg (nitrogen adsorption

method). For comparison, tobacco smoke’s surface area is about 10,000 m2/ kg. Type I and

Type III cements have surface areas of about 300 to 400 m2/kg and 500 to 600 m2/kg

(Blaine), respectively.

The relative density of silica fume is generally in the range of 2.20 to 2.5. Portland cement

has a relative density of about 3.15. The bulk density (uncompacted unit weight) of silica

fume varies from 130 to 430 kg/m3.

Silica fume is sold in powder form but is more commonly available in a liquid. Silica fume is

used in amounts between 5% and 15% by mass of the total cementitious material. It is used in

applications where a high degree of impermeability is needed and in high- strength concrete.

NATURAL POZZOLANS

Natural pozzolans have been used for centuries. The term “pozzolan” comes from a volcanic

ash mined at Pozzuoli, a village near Naples, Italy, following the 79 AD eruption of Mount

Vesuvius. However, the use of volcanic ash and calcined clay dates back to 2000 BC and

earlier in other cultures. Many of the Roman, Greek, Indian, and Egyptian pozzolan concrete

structures can still be seen today, attest- ing to the durability of these materials. The North

American experience with natural pozzolans dates back to early 20th century public works

projects, such as dams, where they were used to control temperature rise in mass concrete and

provide cementitious material. In addition to controlling heat rise, natural pozzolans were

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used to improve resistance to sulphate attack and were among the first materials to be found

to mitigate alkali-silica reaction. The most common natural pozzolans used today are

processed materials, which are heat treated in a kiln and then ground to a fine powder they

include calcined clay, calcined shale, and metakaolin.

CURRENT AVAILABILITY AND USE OF SILICA FUME

Global consumption of silica fume exceeds 1 million tonnes per annum. Silica fume is

generally dark grey to black or off-white in colour and can be supplied as a densified powder

or slurry depending on the application and the available handling facilities. For use in the

UK, it is normally supplied as slurry, consisting of 50% powder and 50% water. In powder

form silica fume is available in bulk, large bags and small bags. If required in bags, these can

be tailored to suit the customers’ needs for handling and batch weight per cubic metre of

concrete. Other applications include fibre cement, gypsum cement, refractory mortars and

castables and in the use of specialised ultra high strength precast sections where strengths of

over 200 N/mm2 can be designed.

COMPATIBILITY WITH ADMIXTURES

Generally chemical admixtures can be used with silica fume in the same way as for

conventional concretes. Silica fume is normally used with a super-plasticiser. As is the case

for OPC cements the performance of admixtures may depend upon the properties of the

individual source of the cementitious material and tests should be carried out to establish the

appropriate dosage levels.

To maximise the full strength producing potential of silica fume in concrete it is

recommended that it should always be used with a dispersant admixture such as high range

water reducing agent (HRWRA). The dosage will depend on the amount of silica fume and

the type of admixture used; see Jahren. The dosage of air-entraining admixture to produce a

required volume of air in concrete usually increases with the amount of silica fume. The

amount of silica fume and the type of mixing were found to have no significant influence on

the development and stability of the air-void system.

WATER DEMAND

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Silica fume can be expected to produce an increased water demand, which is normally

countered by the use of admixtures.

The water demand of concrete containing silica fume increases with increasing amounts of

silica fume. This increase is caused primarily by the high surface area of the silica fume. To

achieve a maximum improvement in strength and durability, silica-fume concrete should

contain a high- range water reducing admixture.

WORKABILITY/CONSISTENCE

Fresh concrete containing silica fume is more cohesive and less prone to segregation than

concrete without silica fume. Experience has shown that it is necessary to increase the initial

slump of concrete with silica fume by approximately 50mm above that required for

conventional CEM I concrete to maintain the same apparent workability. Silica fume addition

has been used to assist in pumping long distances, especially vertically.Concrete was pumped

in a single operation to a height of 601 metres at the Burj Khalifa project in Dubai; so far the

world’s tallest building.

SETTING TIME

Unlike other SCM’s such as slag and fly ash, silica fume does not significantly affect setting

time.

BLEEDING

After concrete has been placed there is a tendency for the solids (aggregates and

cementitious) to settle and displace the water, which is pushed upwards. If the process is

excessive, the water appears as a layer on the surface. The tendency of a concrete to bleed is

affected by the constituents and their proportions, particularly the grading of the fine

aggregate, the water content and any admixtures. Excessive bleeding can produce a layer of

weak laitance on the top of the concrete and may result in plastic settlement cracks but

bleeding can also be beneficial in avoiding plastic shrinkage cracks, which can form on

concrete placed on hot or windy days, where the rate of evaporation of moisture from the

surface exceeds the rate of bleeding.

Concrete containing silica fume shows significantly reduced bleeding. As silica fume dosage

is increased, bleeding will be reduced. This effect is caused primarily by the high surface area

of the silica fume to be wetted; there is very little free water left in the mixture for bleeding, .

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Jahren points out that because of the reduced bleeding, care should be taken to prevent early

moisture loss from freshly placed silica-fume concrete, particularly under conditions that

promote rapid surface drying.

HEAT OF HYDRATION

Silica fume has effectively a similar heat of hydration to CEM I.

A reduction in the early age temperature rise can reduce the risk of early-age thermal

cracking, Early-age thermal crack control in concrete. However a slower release of heat can

reduce the initial rate of strength gain. This may necessitate longer periods before striking

formwork and/or removal of props especially when casting thin, exposed sections in winter

conditions in cooler climates.It also points out that silica fume, when used with a high range

water reducing admixture, can achieve equivalent strength with a reduced binder content

(subject to any minimum limit on binder content) and thereby lower heat output. Papworth et

al calculated theoretically the temperature rise for silica fume concrete and concluded that by

reducing the total binder content of the mix, it can reduce the temperature rise. They then

compare predicted temperature rises with those measured in practical situations. A solution

to providing high early strength couple with low heat was demonstrated in massive silica

fume concrete pours at the Hanford Nuclear Encapsulation facility in the USA.

SENSITIVITY TO CURING

Concrete stiffens and hardens through the hydration reaction between cement and water.

Strength and microstructure, which depend on the degree of hydration, can be adversely

affected if concrete is allowed to dry out at early ages and hydration is prematurely arrested.

The layer close to the surface seems to be the most sensitive, as evidenced by the large effect

of curing on abrasion-resistance. At greater depth, in the region approaching the level of the

reinforcing steel, the effect of curing appears to be less critical. With silica fume, the concrete

may contain very little free water and with significantly reduced bleed there needs to be extra

emphasis on curing so that the surface layer retains the water needed for development of the

properties of the concrete.

To obtain the full benefits of silica fume concrete, proper curing procedures must be

followed. Because concrete containing silica fume shows significantly reduced bleed (as

dosage is increased) there is very little free water left in the mixture for bleeding. This extra

emphasis on curing helps to retain the water needed for development of the desired properties

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of the concrete. Experience shows that under conditions of fast evaporation (wind and sun),

curing measures must be taken immediately after placing the concrete.

EFFECT ON CONCRETE STRENGTH

Strength Development

Figure 1, shows indicative strength development, at a fixed w/c ratio, where concretes

containing fly ash, limestone fines or high-replacement GGBS generally have lower 28-day

strength than CEM I whilst silica fume can give increased 28-day strength.

Figure 3 shows indicative longer-term strength development, where for concretes required to

achieve a specified 28-day strength, those containing GGBS, fly ash and silica fume

generally show increased ultimate strengths.

Figure 3. Indicative Strength Development (at fixed w/c and relative to the 28-day strength

of CEM I)

Notes: 1. The relative strengths are indicative and will vary significantly, with mix design and

materials 2. At fixed w/c, the workability/consistence will vary, according to the water-

demand 3. This graph is derived from experience and data contributed by the authors of

CSTR74

Concrete made with silica fume follows the conventional relationship between compressive

strength and w/c but strength is increased at a given w/c ratio when silica fume is used. High

early compressive strength (in excess of 25N/mm2 at 24 hours) can be achieved. With proper

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concrete design, very high 28-day strengths can be produced, using normal ready-mixed

concrete plants and in the USA and Asia 100–130N/mm2 concretes are used in tall buildings.

Cementitious contents are generally > 400 kg/m3 and w/c in the range 0.30 to 0.40. An

example in South East Asia is the new 79 floor East Island Centre in Hong Kong where the

volume of concrete was reduced by 15% through the use of Grade 100 MPa self-compacting

concrete. Not only were there significant sustainability benefits but also the client benefited

commercially through the additional floor space opened up for rental in this expensive part of

Hong Kong.

EFFECT ON CONCRETE DURABILITY

Permeability

Silica fume can produce very large reductions in water permeability of up to one order

magnitude or more, depending on the mix design and dosage of silica fume.

The reduction in the size of capillary pores increases the probability of transforming

continuous pores into discontinuous one.Because capillary porosity is related to permeability,

the permeability to liquids and vapours is thus reduced by silica fume addition. Silica fume

can produce very large reductions in water permeability, up to an order of magnitude or

more.Data for mortar and concrete show a similar trend in that silica fume reduces

permeability, see for example Scheetz, Grutzek and Strickler, Mehta and Gjørv and Delage

and Aitcin. Maage and Maage and Sellevold reported a reduction in permeability of about

one order of magnitude for silica fume dosages of 5% to 12%; the most improvement was

with the lowest dose that was used with the lowest w/c ratio. Measurement of the water

permeability for quality concrete (40N/mm2) is often impossible because of the measuring

equipment limitations and leakage around the permeability cells, see for example Hustad and

Loland and Hooton. El-Dieb and Hooton were able to measure a water permeability of 1.9 ×

10-16 m/s for a 0.29 w/c concrete with 7% silica fume plus 25% GGBS. The mechanism

involved is due primarily to the high pozzolanic reaction linked with improvement in the

interfacial transition zone.

PROTECTION TO EMBEDDED STEEL (CARBONATION)

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Steel embedded in concrete is protected against corrosion by the alkalinity of the cement

paste. Despite any reduction in calcium hydroxide, resulting from the incorporation of silica

fume, the pH of the cement paste remains at an adequately high level to protect steel.

Carbonation can reduce the alkalinity and protection to the steel. Silica fume concrete tends

to show greater carbonation than CEM I mixes of equivalent 28 day strength.

PROTECTION TO EMBEDDED STEEL (CHLORIDES)

If chloride permeates the concrete to the depth of the reinforcement it can initiate corrosion

of the steel. Concrete made with silica fume is generally substantially more resistant to

chloride diffusion than CEM I concrete and for reinforced concrete structures exposed to

chlorides, its use will give enhanced durability.

SULFATE RESISTANCE

Sulfate attack of concrete occurs through both chemical and physical processes. Two main

reactions are involved, these being the reaction of sulfate ions with hydrated calcium

aluminates forming ettringite, and the combination of sulfate ions with free calcium

hydroxide forming gypsum. The first reaction is of more practical significance. Considerable

increases in volume result from both reactions causing expansion and disruption of the

hardened concrete. More recently, a second form of sulfate attack, called thaumasite attack

has been recognised as a problem after the discovery of its effects on the foundations of some

motorway bridges in the UK. Thaumasite is a calcium silicate sulfo-carbonate hydrate, which

forms at temperatures below 15°C by a reaction between cement paste hydrates, carbonate

and sulfate ions. Its formation reduces the cement paste to a soft mulch. Unfortunately,

conventional Sulfate Resisting Portland Cement offers no protection against the Thaumasite

form of sulfate attack. GGBS, fly ash and silica fume can substantially increase the resistance

to both forms of sulfate attack compared with CEM I concrete.

Detailed recommendations for avoiding sulfate attack using GGBS and fly ash can be found

in Building Research Establishment: Special Digest 1:2005, Concrete in aggressive ground

and the recommendations of this Digest have been adopted by BS 8500:2006. These

documents do not provide any guidance for utilising the increase in sulfate resistance from

incorporating silica fume. For limestone fines concretes, the recommendations for limestone

fines concretes are generally more onerous than for CEM I.

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Silica fume is very effective in reducing or preventing the attack from sodium sulfate, see for

example Carlsson et al., Mather (Ref, Mehta, Hooton, Cohen and Bentur and Sellevold and

Nilsen). The primary mechanism by which silica fume improves sodium sulfate resistance is

by reduction of permeability, see Khatri, and it may be augmented by reduced calcium

hydroxide contents due to pozzolanic reaction. Performance of silica-fume concrete exposed

to ammonium sulfate is mixed Popovic et al. Performance when exposed to magnesium

sulfate is less than that of paste without silica fume Cohen and Bentur.

RESISTANCE TO ACIDS

All types of cement are susceptible to attack by acids and, in highly acid solutions (e.g. pH

less than 3.5), dissolution of the cement matrix and subsequent loss of integrity of concrete

will occur. Some moorland waters with low hardness, containing dissolved carbon dioxide

and with pH values in the range 4–7, may also be very aggressive to concrete, particularly

with continuously flowing water. In general, in such aggressive conditions, the quality of the

concrete has been considered to be of greater importance than the type of cementitious

material.

Luther suggests that silica fume will increase the resistance of concrete to dilute acids and

chemical attack through reduced permeability and through reduced content of calcium

hydroxide, see. Silica- fume concrete is not completely impervious to all aggressive

chemicals, especially in the case of concentrated acid attack on the surface; however,

research and field performance show that at a low w/c, silica-fume concrete can be used

effectively to prevent significant damage by many types of chemical attack including sewage

and silica fume concrete has been specified for use in sewer and outfall pipes in many

countries, see for example Shanghai Institute of Building Science report.

FREEZE-THAW RESISTANCE (FOR COLD WEATHER CLIMATES)

Concrete, which is saturated with water, can be damaged by repeated cycles of freezing and

thawing, and the use of de-icing salts greatly exacerbates the likelihood of attack.

Unfortunately, there is no reliable laboratory test for establishing freeze-thaw resistance and

concrete that is known to have reliable freeze-thaw resistance under real-life conditions, can

often fail when tested by currently available laboratory test methods, see Muller. Freeze-

thaw damage usually shows up as scaling of the surface, exposing the underlying coarse

aggregate. Concretes that may be exposed to freezing and thawing while saturated, need to be

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suitably proportioned and the concrete well cured after placing see Gunter et al and Luther et

al. Air entrainment of the concrete will significantly improve the resistance of concrete to

freeze-thaw damage. Silica fume concrete should be air entrained if exposed to freezing-and-

thawing conditions.

Numerous investigators have shown that it is possible to produce freeze thaw resistant, air-

entrained concrete containing silica fume (see Aïtcin and Vezina; Caldarone et al; Cohen and

Olek; Malhotra; Sonebi and Khayat. In these studies satisfactory freeze thaw durability

factors were obtained at w/c ratios up to 0.60. Yamato et al and Malhotra et al suggest that,

for freeze thaw resistance, the silica fume content should be limited to a maximum of 15%.

Saucier et al conclude that it is vital to check admixture compatibility and to perform tests

with the actual materials to be used in order to ensure that the air-entraining admixture is

effective and that a stable air-void system can be produced. ACI 234R-2006 concludes that

the data for silica-fume concrete without entrained air is conflicting and recommends that

silica fume concrete should be air entrained where adequate resistance to freezing- and-

thawing conditions is required.

ALKALI-SILICA REACTION

Alkali-silica reaction (ASR) is a reaction between the hydroxyl ions in the pore water within

concrete and certain forms of silica, which occur as part of some aggregates. The product of

the alkali-silica reaction is a gel which imbibes pore fluid and expands; in some instances this

expansion induces internal stress in the concrete of such magnitude that extensive macro-

cracking of the concrete occurs. The damage occurs in parts of the concrete structure exposed

to moisture. Silica fume can reduce the risk of damage due to ASR.

The use of silica fume in sufficient quantity and properly dispersed in concrete, either on its

own or in combination with other pozzolans or GGBS, can be an effective means of

combating ASR, as evidenced by decades of field experience in addition to laboratory tests.

Gudmundsson and Olafsson report the effect of silica fume on the expansion of materials

from Iceland, where the entire production of cement contains 7–10% silica fume in order to

reduce the ASR caused by a combination of highly reactive natural aggregates and the local

high alkali cement.

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ABRASION RESISTANCE

Numerous factors influence the abrasion resistance of floor slabs, the most significant being

curing, strength class and trowelling intensity. Curing appears to be more important for

abrasion resistance than changes in constituent materials. For example, the difference

between immediate exposure and seven days covered with polythene can be as much as an

order of magnitude in terms of abrasion resistance. When a good standard of curing is

applied, e.g. wet curing for seven days or the application of a 90% efficiency resin

compound. Silica fume can increase abrasion resistance through increased strength Silica

fume will increase the abrasion-erosion and abrasion resistance of concrete through increased

strength of the matrix and the improved bond between matrix and aggregates. The excellent

resistance of silica fume concrete to abrasion erosion damage was reported by Holland and

McDonald based on investigations performed at the U.S. Army Corps Engineers Waterways

Experiment Station (WES). The abrasion-resistance test method used was developed by the

WES (see Liu, which is now ASTM C 1138. This method uses steel balls in water stirred by

paddles at 1200 rpm to simulate the abrasive action of waterborne particles such as silt, sand,

gravel, and boulders. In the UK proprietary special concretes have been developed for

specific applications such as waste transfer stations, sea defence construction and hard

wearing floors. Applications of silica fume concrete in dams has proven beneficial to increase

service life and thin surface applications containing silica fume have been developed for

industrial floors and highway repairs.

RESISTANCE TO FIRE

There is no evidence to suggest that the type of cementitious material will have a large effect

on the resistance to fire. In some cases of extremely low permeability concrete, explosive

spalling has been reported

A number of researchers have demonstrated that the fire performance of silica-fume concrete

is little different from that of conventional concrete, see for example Jensen and Aarup and

Dumuolin and Behloul. Properties such as thermal conductivity and specific heat do not

change significantly, and there is evidence that properties during the fire and residual

properties are actually better for silica- fume concrete. Research by Phan and Carino indicates

that for high-strength concrete, the relative amount of residual strength may be less than that

in conventional-strength concrete. This is in part due to the reduced content of calcium

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hydroxide in concrete with pozzolans, which means that less water is released at high

temperatures, see Chan, Peng and Chan, Chan, Peng and Anson and Saad et al.

In some cases of extremely low permeability, silica fume concrete, explosive spalling has

been reported. While silica fume content as such is not the governing parameter, the low

permeability often associated with a low w/c and silica fume may require preventative

measures. Section 6.2, Spalling, in Part 1-2 of Eurocode 2 (General rules – Structural fire

design) suggests that no special precautions need be taken for concretes up to C80/95

provided that the silica fume content is below 6% by weight of cement. For higher silica

fume contents, and for concrete grades above C80/95, various precautionary measures are

recommended including the provision of at least 2kg/m3 of monofilament polypropylene

fibres.

EFFECT ON CONCRETE’S PHYSICAL PROPERTIES

Colour

Although the curing time and formwork type can have some effect, the colour of concrete is

principally determined by the colour of the cementitious material. Although ‘white cements’

are available at a price, CEM I is normally a shade of grey. Most silica fumes range from

light to dark grey. Because SiO2 is colourless, the colour is determined by the non-silica

components, which typically include carbon and iron oxide. In general, the higher the carbon

content, the darker the silica fume. The carbon content of silica fume is affected by many

factors relating to the manufacturing process, such as: use of wood chips versus coal, wood

chip composition, furnace temperature, furnace exhaust temperature, and the type of product

(metal alloy) being produced. Almost white coloured silica fume is available for use in

architectural concrete.

Elastic Modulus

GGBS, fly ash or silica fume usually increase the ultimate modulus, but the magnitude of the

increase is generally not significant in terms of design. Limestone fines has little effect.

Sellevold et al found that the dynamic modulus of elasticity increases with increasing silica-

fume content in pastes. Helland, Hoff and Einstabland concluded that the stress-strain

behaviour of silica- fume concrete was similar to that of concrete without silica fume. Several

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other researchers have reported that the static modulus of elasticity of silica-fume concrete is

apparently similar to that of concrete without silica fume of similar strength, see for example

Luther and Hansen; Løland and Hooton. However, Burg and Ös reported that concrete

incorporating 15% silica fume as an addition had a higher modulus of elasticity than the

control concrete without silica fume, regardless of curing conditions. Wolsiefer reported a

modulus of elasticity of 43.1kN/mm2 and a Poisson’s ratio of 0.21 for a 98N/mm2

compressive strength silica-fume concrete. Saucie studied five silica-fume concretes and

found Poisson’s ratios ranging in value from 0.208 for 92N/mm2 concrete to 0.256 for

113N/mm2 concrete. Iravani obtained Poisson’s ratios ranging from 0.16 to 0.20, including

0.18 for a 105N/mm2 strength, 31.7kN/mm2 modulus silica-fume concrete, and 0.19 for a

120N/mm2 strength, 37.1kN/mm2 modulus silica-fume concrete cured for 3 weeks at 100%

relative humidity and then for 5 weeks at 50% relative humidity. The range of these values

for Poisson’s ratio (0.16 to 0.256) are similar to what would be expected for CEM I concrete.

Creep

Under conditions of no moisture loss, lower creep values will be found when using GGBS or

fly ash in concrete in comparison to CEM I concrete of a similar strength class. This is

generally associated with the greater strength gain of the GGBS or fly ash concretes during

the period under load. Such conditions are likely with concrete which is remote from the

cover zone, particularly in large sections. In many other practical situations (i.e. beams,

columns, slabs), where there is significant long-term drying, the strength gain may be

negligible and the creep characteristics of the different types of concrete will be similar. The

creep of silica-fume concrete should be no higher than that of concrete of equal strength class

without silica fume. Where the load is applied at an age less than 28-days, the lower early-

strengths of GGBS or fly ash concretes may result in increased creep, see Bamforth et al.

Limited published data and the different nature of the creep tests used by various

investigators make it difficult to draw specific conclusions on the effect of silica fume on the

creep of concrete. Wolsiefer examined concretes loaded from both 12 hours and 28 days up

to 4 months. He found that the silica fume concretes exhibit less creep than would have been

expected from control concrete of equivalent strength. Penttala studied high strength

concretes with 10% silica fume addition and found that the creep was 20% less than

theoretical predictions. Tomaszewicz concluded that the creep coefficient of a C80 silica

fume concrete was lower than a control C30 concrete.

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Tensile Strain Capacity Concrete Society Digest 2, Mass concrete suggests that concrete

containing GGBS or fly ash might exhibit marginally more brittle failure characteristics, with

the tensile strain capacity being slightly lower than for a similar strength class CEM I

concrete. However data on the effects of cementitious materials on the tensile strain capacity

of concrete is very limited.

Drying Shrinkage

Because of the differing conditions under which tests have been carried out, it is difficult to

make direct comparisons between the effects of different cementitious materials.

Long-term total shrinkage of silica-fume concrete is comparable to that of concrete without

silica fume of otherwise similar composition. Jahren found that shrinkage was of the same

order as that of control concretes with emphasis on good curing. Drying shrinkage data on

concrete containing 20% silica fume have been published by Wolsiefer, who found that

shrinkage values for the silica fume specimens were 24% lower than those of similar but

lower strength concrete made without silica fume. Khatri and Sirivivatnanon reported that the

incorporation of 10% silica fume as replacement for CEM I reduced the long-term drying

shrinkage of the concrete after 28 days; however, it increased the early-age shrinkage after an

initial curing of 7 days in lime water.

Micro filler effect:

Silica Fume is an extremely fine material, with an average diameter 100 times finer than

cement. At a typical dosage of 8% by weight of cement, approximately 100,000 particles for

each grain of cement will fill the water spaces in fresh concrete. This eliminates bleed and the

weak transition zone between aggregate and paste found in normal concrete. This micro filler

effect greatly reduces permeability and improves paste-to aggregate bond in SF concrete

compared to conventional concrete3. The silica fume reacts rapidly providing high early

strength and durability. The efficiency of silica fume is 3-5 times that of OPC and

consequently concrete performance can be improved drastically.

20

Verma ajay et al, (2012) have studied the effect of micro silica and the strength of concrete

with ordinary Portland cement. They observed that silica fume increases the strength of

concrete and reduces capillary pores. Dilip Kumar Singha Roy (2012) has investigated on

the strength parameters of concrete made with partial replacement of cement by SF.

Dilip Kumar Singha Roy (2012) has investigated on the strength parameters of concrete

made with partial replacement of cement by SF.

T.Shanmugapriya (2013) studied the influence of silica fume on M50 concrete and found

that 10% of silica fume replacement increases the maximum compressive strength, split

tensile strength and flexural strength.

Mohammad Reza Zamani Abyaneh, et al (2013) have found that the concrete produced with

Micro-SiO2 and Nano-SiO2 show higher degrees of quality in their compressive strength

than the concrete which only have Micro-SiO2 in their mixtures. Specimens with 2% Nano-

SiO2 and 10% Micro-SiO2 had less water absorption and more electrical resistance.

21

CHEMICAL ADMIXTURE

4.1 CEMCRETE SP25:

The basic components of CEMCRETE SP are synthetic polymers, which allow mixing water

to be reduced considerably and concrete strength to be enhanced significantly, particularly at

the early ages. CEMCRETE SP is chloride free product.

Advantages:

CEMCRETE SP makes the concrete highly flowable, with low water/ cement ratio and

improves strength of concrete when compared with normal concrete with same workability.

Due to the reduction in water cement ratio, all other properties like permeability, shrinkage,

creep, workability and modulus elasticity will be improved.

TYPICAL PROPERTIES

1) CEMCRETE SP is a brown free flowing liquid.

2) Specific gravity: 1.20+0.035

3) Chloride content: Nil to BS 5075 to I.S:456-78

4) Nitrate content: Nil

5) Freezing point: 0°C. Can be reconstituted if stirred after thawing.

6) Air entrainment: Maximum 0.5%.

Dosage

0.2 to 0.5% by weight of the cement depending upon the condition of the materials and

conditions. Trail mixes are recommended prior to production of concrete.

22

5. Mix design

Concrete mix design is defined as the appropriate selection and proportioning of constituents

to produce a concrete with pre-defined characteristics in the fresh and hardened states.

In general, concrete mixes are designed in order to achieve a defined workability, strength

and durability .

The selection and proportioning of materials depend on:

the structural requirements of the concrete

the environment to which the structure will be exposed

the job site conditions, especially the methods of concrete production, transport,

placement, compaction and finishing

the characteristics of the available raw materials

Mix design is carried out for M50 grade concrete as per IS: 10262-2009 and IS: 456-2000 for

Normal concrete and for partially replaced cement with silica fume for 5 to 12.5%

replacement.

23

5.1 Mix design for Normal concrete

1) Determine Target mean strength of concrete as:

ft= fck+ k. s

ft= target mean compressive

Where,

ft= target mean compressive strength at 28 days,

fck= Characteristic compressive strength of concrete at 28 days,

k = usually 1.65 as per is 456-2000

s = standard deviation.

From table 1 of IS 10262:2009

S.N.O GRADE OF CONCRETE ASSUMED STANDARD DEVIATION

N/mm2

1 M10,M15 3.5

2 M20,M25 4.0

3 M30,M35,M40,M45,M50, 5.0

Step 2: selection of w/c ratio:

Choose w.c.ratio against max w.c.ratio for the requirement of durability. (Table 5, IS:456-

2000)

Make a more precise estimate of the preliminary w/c ratio corresponding to the target average

strength.

Water cement ratio is selected based on strength criteria and durability criteria given from the

following graph of the plain concrete.

24

The obtained water cement ratio has been checked against the limiting water cement ratio as

given in table 2 and the least of the two values have been taken.

Step 3: selection of water content:

Water Content is influenced by

Aggregate size

Aggregate shape and texture

Workability required

Water cement ratio

Cementations material content

Environmental exposure condition

Based on Aggregate size the water content is selected.

S.N.O Nominal Maximum size

of Aggregate (mm)

Maximum water content

(kg)

1. 10 208

2. 20 186

3. 40 165

Maximum water content for 20mm aggregate = 186 litre (for 25 to 50mm slump range)

25

For 100mm slump the water content = 186+(6/100)x186=197 litre

Super plasticizer

As super plasticizer is used. The water content can be reduced up 30 percent.

Based on trials with super plasticizer reduction of water content percent has to be selected .

Step 4 –Calculation of Cementations Material

Calculate the cement content from W/C ratio and final water content arrived after adjustment.

Check the cement content so calculated against the min. cement content from the requirement

of durability. Adopt greater of the two values.

Satep – calculation of cement and silica fume content

Now, to proportion a mix containing silica fumr the following steps are suggested:

a) Decide the percentage silica fume to be used based on project requirement and quality of

materials.

b) In certain situations increase in cernentitious material content may be warranted, The

decision on increase in cementitious material content and its percentage may be based on

experience and trial

NOTE - This illustrative example is with increase of 10 percent cement itious material

content.

Step 6 –Estimation of Coarse Aggregate Proportion

For W/C ration of 0.5 use following Table

26

Correction in Coarse Aggregate values

The table specified for W/C ratio of 0.5

1. For Every +0.05 change in W/C ratio: -0.01

2. For Every -0.05 change in W/C ratio: +0.01

3. For Pumpable Mix : -10 %

Step 7 –Estimation of Fine Aggregate Proportion

Fine Aggregate =1- coarse Aggregate proportion

27

5.2 MIX CALCULATIONS

The mix calculations per unit volume ofconcrete shall be as follows:

1)Volume of Concrete= 1 m3

2)Volume of Cement= (Mass of Cement / SG of Cement) * 1/1000

3)Volume of Water= (Mass of Water / SG of Water) * 1/1000

4)Volume of Chemical Admixture

(2 % of Mass of cementations material) = (Mass of Admixt. / SG of Admixt) * 1/1000

5)Volume of All in Aggregates= [a -( b + c + d )]

6)Mass of Coarse aggregate= e * Volume of coarse aggregate * SG of coarse aggregate *

1000

7)Mass of fine aggregate= e * Volume of fine aggregate * SG of fine aggregate * 1000

F)Mix proportions for :

Cement = Kg/m3

Water = Kg/m3

Fine aggregate = Kg/m3

Coarse aggregate = Kg/m3

28

6.Tests on Fresh concrete

The behaviour of green or fresh concrete from mixing up to compaction depends mainly on

the property called Workability of concrete. In general terms, Workability of work which is

to be done to compact the concrete in a given mould.

The desired Workability for a particular mix depends upon the type of compaction adopted

and the complicated nature of reinforcement used in reinforced concrete. A workable mix

should not segregate. Workable concrete is the one which exhibits very little internal friction

between particle & particle or which overcomes the frictional resistance offered by the

formwork surface or reinforcement contained in the concrete with just the amount of

compacting efforts forthcoming.

Measurement of Workability

The workability of concrete is determined with the help of Slump cone test .In this test fresh

concrete is filled in a mould of specified shape and dimensions & the settlement or slump is

measured when supports mould is removed.

Slump cone test conducted on nominal concrete

29

The slump value is a measure indicating the consistency or Workability of cement concrete.

It gives an idea of water content needed for concrete to be used for different works. A

concrete is said to be workable if it can be easily mixed, placed, compacted and finished .A

workable concrete should not show any segregation or bleeding. Segregation is said to occur

when coarse aggregate tries to separate out from the finer material and a concentration of

coarse aggregate at one place occurs. This results in large voids, less durability and

strength .Bleeding of concrete is said to occur which excess water comes up at the surface of

concrete .This causes small pores through the mass of concrete and is undesirable.

By this test we can determine the water content to give specified slump value.

30

3.6 Tests on Hardened concrete

Concrete cubes of sizes 150mm X 150mm X 150mm were prepared with percentage

replacement of cement with silica fume and are cured under normal conditions as IS code and

were tested for 7,14,28 days for determining the compressive strength.

31

CHAPTER-4

NOMINAL CONCRETE OF M50 GRADE

32

Mix Design for Normal concrete

The mix proportioning for a concrete of M 50 Grade with W/C ratio 0.35

A-1 STIPULATIONS FOR PROPORTIONING

a) Grade designation : M 50

b) Type of cement : OPC53 grade conforming to IS 8112

c) Maximum nominal size of aggregate : 20mm

d) Minimum cement content : 400Kg/m3

e) Maximum water-cement ratio : 0.38

f) Workability : 100mm(slump)

g) Exposure condition : Severe (for reinforced concrete)

h) Method of concrete placing : pumping

i) Degree of supervision : Good

j) Type of aggregate : Crushed angular aggregate

k) Maximum cement content : 428Kg/m3

l) Chemical admixture type : Super plasticizer

A-2 TEST DATA FOR MATERIALS

a) Cement used : OPC grade conforming to IS 8112

b) Specific gravity of cement : 3

c) Chemical admixture : Super plasticizer conforming to IS 9103

d) Specific gravity of:

1) Coarse aggregate : 2.67

2) Fine aggregate : 2.60

e) Water absorption:

1) Coarse aggregate : 0.5 percent

2) Fine aggregate : 1.0 percent

f) Free (surface) moisture

1) Coarse aggregate : Nil (absorbed moisture also nil)

2) Fine aggregate : Nil

33

g) Sieve analysis

1) Fine aggregate : Conforming to grading Zone I of table 4 of IS 383

A-3 TARGET STRENGTH FOR MIX PROPORTIONING

F’CK = FCK + 1.65S

= 50+1.65 x 5 = 58.25 N/mm2.

Where

f’ck = target average compressive strength at 28 days

fck = characteristic compressive strength at 28days, and

s = standard deviation.

From table 1 of IS 10262:2009, s = 5 N/mm2

A-4 SELECTION OF WATER-CEMENT RATIO

Based on experience, adopt water-cement ratio as 0.38

Selection of water content:

From table 2 (IS 10262:2009)

Maximum water content for 20mm aggregate = 186 litre (for 25 to 50mm slump range)

estimated water content for 100mmslump=186+ 6100

X 186

= 197 litre

As super plasticizer is used. The water content can be reduced up to 30 percent.

Based on trials with super plasticizer water content reduction of 25 percent has been

achieved, Hence, the arrived water content = 197 x 0.75 = 148 litres

CALCULATION OF CEMENT CONTENT

w/c ratio = 0.38

Cementitious material (cement + silica fume) content =148/0.38= 389.47kg/m

34

Now, to proportion a mix containing silica fume the following steps are suggested:

a) Decide the percentage silica fume to be used based on project requirement and quality of

materials.

b) In certain situations increase in cernentitious material content may be warranted, The

decision on increase in cementitious material content and its percentage may be based on

experience and (trial Note),

NOTE - This illustrative example is with increase of 10 percent cementitious material

content.

Cementitious material content = 389.47 x 1.10 = 428.4 kg/m

Water content = 148 litres

Water-cement ratio = 148/428.4 = 0.35

Volume of coarse aggregate = 0.63

Volume of fine aggregate content = 1 – 0.63

= 0.37

Mix calculations:

The mix calculations per unit volume of concrete shall be

a)Volume of concrete = 1m3

b¿Volumeof cement= massof cementspecific gravity of cement

X 11000

=428.43.0

X 11000

= 0.143 m3

c ¿Volumeof water= mass of waterspecific gravity of water

X 11000

35

= 148

1X 1

1000

= 0.148m3

a) chemical admixture = 9.3/1.20 x 1/1000 = 0.0077

(@ 2% of cemintituios material)

e)Volume of all in aggregate = a – (b+c+d)

= 1- (0.143+0.148+0.0077)

= 0.70

f) Mass of coarse aggregate = e X volume of coarse aggregate X specific gravity of

c oarse aggregate X 1000

= 0.70 X 0.63 X 2.67 X 1000

= 1177.5Kg

g)Mass of fine aggregate = e X volume of coarse aggregate X specific gravity of

Coarse aggregate X 1000

= 0.70 X 0.37 X 2.60 X 1000

= 673.4 Kg

h)Mix proportions

Cement = 428.4Kg/m3

Water = 148 Kg/m3

Fine aggregate = 673.4 Kg/m3

Coarse aggregate = 1177.5 Kg/m3

The mix proportion is Cement : F.A : C.A

1 : 1.57 : 2.74

36

4.2 Sample test results for compressive strength :

The casted cubes were tested for their compressive strength for 7, 14 & 28 days and the

results are tabulated as follows.

7 days testing :

S.N.O PEAK LOAD (kN) PEAK STRESS (Mpa)

Sample 1 1135 50.43

Sample 2 1196 53.20

Sample 3 1184 52.58

Average 1171.66 52.08

14 days testing:


Sample 1 1256 55.74

Sample 2 1340 59.56

Sample 3 1204 52.92

Average 1266.6 56.07

28 days testing :


Sample 1 1365 60.62

Sample 2 1254 55.70

Sample 3 1387 61.64

Average 1335.33 59.32

37

CHAPTER - 5

CEMENT REPLACED WITH SILICA FUME

38

5.1 Mix design for 5% replacement of Cement with Silica Fume:

Mix proportions :

1. Cement = 428.4 Kg/m3

2. Water = 148 Kg/m3

3. Fine aggregate = 673.4Kg/m3

4. Coarse aggregate = 1177.5 Kg/m3

The mix proportion is C : F.A : C.A

1 : 1.57 : 2.75

For 5 % replacement :

1. Weight of cement = 1.373 kg

2. Weight of Silica Fume = 0.072 kg

3. Weight of Fine aggregate = 2.27 kg

4. Weight of Coarse aggregate = 3.974 kg

For 9 Cubes :

1. Weight of cement = 12.357 kg

2. Weight of silica Fume = 0.648 kg

3. Weight of Fine aggregate = 20.43 kg

4. Weight of Coarse aggregate = 35.766 kg

39

5.2 Sample test results for compressive strength:

The casted cubes were tested for their compressive strength for 7, 14 & 28 days and the


7 days testing :


Sample 1 1280 56.86

Sample 2 1224 54.42

Sample 3 1324 58.83

Average 1276 56.70

14 days testing:


Sample 1 1383 61.34

Sample 2 1314 58.40

Sample 3 1365 60.66

Average 1354 60.13

28 days testing :


Sample 1 1409 62.43

Sample 2 1378 61.24

Sample 3 1486 65.76

Average 1424.3 63.14

40

5.3 Mix design for 7.5 % replacement of Cement with Silica Fume:

Mix proportions :

1. Cement = 428.4 Kg/m3

2. Water = 148 Kg/m3

3. Fine aggregate = 673.4Kg/m3

4. Coarse aggregate = 1177.5 Kg/m3


1 : 1.57 : 2.75

For 7.5 % replacement :

1) Weight of cement = 1.337 kg

2) Weight of Silica Fume = 0.108 kg

3) Weight of Fine aggregate = 2.27 kg

4) Weight of Coarse aggregate = 3.974 kg

For 9 Cubes :

1) Weight of cement = 12.033kg

2) Weight of silica Fume = 0.972 kg



41


The casted cubes were tested for their compressive strength for 7 ,14 & 28 days and the


7 days testing :


Sample 1 1326 58.84

Sample 2 1373 60.28

Sample 3 1337 59.34

Average 1345.3 59.34

14 days testing:


Sample 1 1496 66.48

Sample 2 1443 64.13

Sample 3 1388 61.68

Average 1442.3 64.09

28 days testing :


Sample 1 1478 65.68

Sample 2 1502 66.75

Sample 3 1485 66.00

Average 1488.3 66.14

42

5.5 Mix design for 10 % replacement of Cement with Silica Fume:

Mix proportions :

1) Cement = 428.4 Kg/m3

2) Water = 148 Kg/m3

3) Fine aggregate = 673.4Kg/m3

4) Coarse aggregate = 1177.5 Kg/m3


1 : 1.57 : 2.75

For 10 % replacement :





For 9 Cubes :





43

5.6 Sample test results for compressive strength



7 days testing :


Sample 1 1474 65.51

Sample 2 1390 61.76

Sample 3 1439 63.95

Average 1434.33 63.74

14 days testing:


Sample 1 1485 66.00

Sample 2 1542 68.53

Sample 3 1540 68.46

Average 1522.33 67.66

28 days testing :


Sample 1 1603 72.44

Sample 2 1562 69.43

Sample 3 1634 72.62

Average 1599.66 71.49

44

5.7 Mix design for 12.5 % replacement of Cement with Silica Fume:

Mix proportions :

1) Cement = 428.4 Kg/m3

2) Water = 148 Kg/m3

3) Fine aggregate = 673.4Kg/m3

4) Coarse aggregate = 1177.5 Kg/m3


1 : 1.57 : 2.75

For 12.5 % replacement :





For 9 Cubes :





45




7 days testing :


Sample 1 1284 57.08

Sample 2 1268 56.35

Sample 3 1322 58.75

Average

1291.33 57.39

14 days testing:


Sample 1 1386 61.60

Sample 2 1398 62.13

Sample 3 1484 65.95

Average 1403.3 63.23

28 days testing :


Sample 1 1454 64.62

Sample 2 1444 64.17

Sample 3 1472 65.42

Average 1456 64.73

46

CHAPTER -6

RESULTS AND DISCUSSIONS

47

6.1 Test results on Fresh concrete:

The slump value is a measure indicating the consistency or Workability of cement

concrete.It gives an idea of water content needed for concrete to be used for different works.

A concrete is said to be workable if it can be easily mixed,placed, compacted and finished.

The obtained results are tabulated as follows:

Percentages of Silica Fume Slump value obtained (mm)

0% 95

5% 82

7.5% 77

10% 71

12.5% 68

Graph:

Result: the following graph shows that by adding different percentages of silica fume the

workability is reducing.

48

6.2 Tests on Hardened Concrete:

Concrete cubes of sizes 150mmx150mmx150mm were prepared with percentage replacement

of cement with silica fume and are cured under normal conditions as IS code and were tested

for 7,14,28 days for determining compressive strength.

Table : Compressive strength for 0% replacement of cement for Silica Fume

Age of Curing of Cubes Compressive strength (Mpa)

7 52.07

14 56.29

28 59.34

Graph:

Result : The following graph shows that the compressive strength of normal concrete for 28

days is 59.34 N/mm2.

49



7 56.70

14 60.17

28 63.30

Graph:

Result: The following graph shows that the compressive strength of 5% silica fume contain

concrete for 28 days is 63.30 N/mm2 .which is 6.25% increase in strength when compare to

the normal concrete.

50

Table : Compressive strength for 7.5 % replacement of cement for Silica Fume


7 59.79

14 64.10

28 66.14

Graph:

Result: The following graph shows that the compressive strength of 7.5% silica fume contain

concrete for 28 days is 66.14 N/mm2. Which is 10.28% increase in strength when compare to

normal concrete.

51



7 63.74

14 67.65

28 71.07

Graph:

Result: The following graph show that the compressive strength of 10% silica fume contain

concrete is 70.28 N/mm2. Which is 16.5% increase in strength when compare to the normal

concrete.

52

Table : Compressive strength for 12.5 % replacement of cement for Silica Fume


7 57.36

14 62.36

28 64.73

Graph:

Result: The following graph show that the compressive strength of 12.5% silica fume contain

concrete for 28 days is 65.46 N/mm2. Which is 10.3% increase in strength when compare to

normal concrete.

53

Comparison of Strengths of Normal and Silica Fume concretes:

From the graph studies a comparative conclusion can be drawn from the strengths of normal

and silica fume concretes and we can know which one does gives high strength.

Graph

Result: The following graph show that the maximum strength achieved is at 10% silica

fume contain concrete . The results indicate that for the concrete mix and silica fume used

in this study, the optimum replacement level of silica fume is about 10%.

54

CHAPTER -7

CONCLUSIONS AND

FURTHER SCOPE OF WORK

55

Conclusion

Its shows that at 10% of silica replaced concrete has given more strength when

compare to the normal concrete.

Silica fume also decrease the voids in concrete.

The incorporation of silica fume in concrete has a marginal influence on the density of

concrete.

The results indicate that for the concrete mix and silica fume used in this study, the

optimum replacement level of silica fume is about 10%.

56

Further Scope of Work

The durability related tests such as

Saturated Water Absorption (SWA) test

Porosity test

Sorptivity test

Permeability test

Acid resistance test

Sea water resistance test

Abrasion resistance test

Impact resistance test

57

Chapter 8

Bibliography

58

REFERENCES

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concrete with ordinary Portland cement” Reaserch journal of Engineering Science ISSN

2278-9472 vol.1(3), 1-4, sept (2012).

Dilip Kumar Singha Roy “Effect of Partial Replacement of Cement by Silica Fume on

Hardened Concrete”. International journal of engineering Technology and Advanced

Engineering (ISSN 2250-2459, volume 2, issue 8, August 2012).

T. Shanmugapriya, Dr. R. N. Uma “Experimental Investigation on silica Fume as partial

replacement of Cement in High Performance Concrete”. (IJES) 2013.

IS 456-2000, "Indian Standard Code of Practice for plain and reinforced concrete” Fourth

revision, BIS, New Delhi.

IS 383-1970, "Indian Standard Specification for coarse and fine aggregate from natural

source for concrete,” 2nd Edition, BIS, New Delhi.

IS 2386-1963, "Indian Standard Methods of tests for aggregate” BIS, New Delhi.

IS: 12269-1987, “Indian Standard Ordinary Portland Cement 53 grade Specification” BIS,

New Delhi.

IS: 10262-1982, “Recommended guidelines for concrete mix design, “BIS, New Delhi.

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Shetty M.S., Concrete Technology, S. Chand and Company Pvt Ltd. New Delhi, India

(1999)

Ha-Won Song, Seung-Woo Pack, Sang-Hyeok Nam, Jong- Chul Jang and Velu Saraswathy,

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material, 24, 315-321 (2010)

Abdullah A. Almusallam, Hamoud Beshr, Mohammed Maslehuddin and Omar S.B. Al

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concrete, Cement and Concrete Composites, 26, 891–900 (2004)

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Krishna M.V., Rao P., Kumar Ratish and Khan Azhar M., A study on the influence of curing

on the strength of a standard grade concrete mix, Architecture and Civil Engineering, 8(1),

23–34 (2010)

Bhanjaa S. and Sengupta B., Influence of silica fume on the tensile strength of concrete,

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ACI report 234R-96 (2000)

60