CHAPTER ONE

INTRODUCTION

1.1 GENERAL OVERVIEW

Concrete is a stone-like material, that is made by mixing cement, water, fine aggregate (often

sand), coarse aggregate and frequently other additives (that modify properties) into a workable

mixture. Concrete is seen as a carefully proportioned mixture of cement, water, fine aggregate,

and coarse aggregate. To these basic components a variety of admixtures, that is, chemicals that

influence the reaction or modify the physical properties of the hardened concrete, are frequently

added. As soon as the components of concrete have been mixed together, the cement and the

water reacts to produce a cementing gel that bonds the fine and coarse aggregates into a stone-

like material. The product so formed is cured for handling. The essential ingredients of concrete

are cement and water, which react with each other chemically, to form another material that have

useful strength. The strength of concrete depends on

The qualities of the ingredients.

Their relative quantities.

The manner in which they are mixed, compacted and cured.

Cement and water interact chemically to bind the aggregate particle into a solid mass. The

chemical reaction between the cement and water, results in an exothermic reaction producing

significant quantities of heat referred to a hydration.

Cement is produced by burning together, in a definite proportion, a mixture of silicious

(containing silica), argillaceous (containing aluminium) and calcareous (containing lime)

material in partial fusion, at a temperature of 1400°C to 1450°C. By doing so, a material called

clinker is obtained. It is cooled and then grounded to the required fineness to get cement. A

cementitous material is one that has the adhesive and cohesive properties necessary to bond inert

aggregates into a solid mass of adequate strength and durability. The cement used in the making

of concrete are called hydraulic cement, because they have the tendency to react chemically with

water in an exothermic process thereby resulting into a water – resistant products. Due to

hydration, setting and hardening of cement takes place.

Admixtures are materials other than the main constituents of concrete that are added to the

materials that have an impact on the properties of the concrete. These admixtures could be in the

form of chemical admixtures or mineral admixtures. In this work, the mineral admixture that is

added to the concrete is fly ash while the chemical admixture that is added to the fresh concrete

on mixing is a super – plasticizer in the form of conplast SP430.

Fly ash is the finely divide residue that results from the combustion of pulverized coal that is

carried from the combustion chamber of a furnace by exhaust gases. .Fly ash usually refers to ash

produced during combustion of coal. Depending upon the source and makeup of the coal being

burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts

of silicon dioxide (SiO2) (both amorphous and crystalline) and calcium oxide (CaO), both being

endemic ingredients in many coal-bearing rock strata. There is a growing use of fuel ash in

concrete, particularly where the concrete is required to have specific properties. Fuel ash is used

to replace some of the cement in the mix but in order to have concrete having the same strength

at 28 days, the combined mass of the cement plus fuel ash needs to be greater than that of the

cement in a cement only mix. Fuel ash which is suitable for concrete initially assists in reducing

the water demand of the concrete, but later, acting as a pozzolona, it increases the strength of the

concrete. Pozzolonas, including fuel ash, react in the presence of moisture with the calcium

hydroxide released by the hydration of the Portland cement to form additional strength –

producing compounds at later ages (BRE, 1997). The positive effects of using fly ash in concrete

are better quality of concrete, eco-friendly and preservation of resources. Construction of power

plants require huge quantity of concrete and use of fly ash, as pozzolanic material, can improve

the durability of structure, thereby enhancing the safety of plants and also economy in the life

cycle cost of the plant. ASTM C618 (AASHTO M 295) Class F and Class C fly ashes are

commonly used as pozzolanic admixtures for general purpose concrete. Class F materials are

generally low – calcium (less than 10% CaO) fly ashes with carbon contents usually less than

5%, but some may be as high as 10%. Class C materials are often high – calcium (10% to 30%

CaO) fly ashes with carbon contents less than 2%. Many Class C ashes when exposed to water

will hydrate and harden in less than 45 minutes. Some fly ashes meet both Class F and Class C

classifications. Higher CaO content generally denotes higher self – cementing properties. Fly ash

in concrete reduces drying shrinkage (Atis, 2003), thus generates fewer cracks which ensure

greater resistance to deterioration. Chindaprasirt et al. (2004) found reduced drying shrinkage of

mortars using fly ashes of different fineness. Though the drying shrinkage is influenced by many

factors, the results indicated that the water to cement ratio was the prime factor. By replacing up

to 45% class F fly ash, reduced pore diameter and porosity of concrete were observed at 28 days,

whereas fly ash-cement paste revealed increased porosity (Poon et al. 2000). Papadakis (1999)

observed increased porosity when Class F fly ash replaced cement and decreased porosity when

fly ash replaced aggregate in mortar.

Conplast SP430 (BS) is based on Sulphonated Naphthalene Polymers and is supplied as a brown

liquid instantly dispersible in water. Conplast SP430 (BS) has been specially formulated to give

high water reductions up to 25% without loss of workability or to produce high quality concrete

of reduced permeability.

Over the years, the use of concrete in the construction of structures had been with the use of

cement, but as time passes the use of some partial replacement materials had been investigated.

The use of fly ash as partial replacement with cement will provide an alternative to the use of

cement in the making of concrete for civil engineering structures, thereby resulting in the

reduction in the cost of civil engineering construction projects. Fly ash utilization, especially in

concrete, has significant environmental benefits including:

1) increasing the life of concrete roads and structures by improving concrete durability,

2) net reduction in energy use and greenhouse gas and other adverse air emissions when fly

ash is used to replace or displace manufactured cement,

3) reduction in amount of coal combustion products that must be disposed in landfills, and

4) conservation of other natural resources and materials.

1.2 STATEMENT OF THE PROBLEM

Concrete has been the major component of most structures. The major constituent of concrete is

cement which causes the binding of the other components together. Due to the cost of having

cements, many engineers have been in search of materials that can be added to the cement so as

to have a positive impact on the cement, thereby increasing the properties of concrete. This study

involves replacing cement partly with the use of fly ash in percentages of the weight of the

cement and then adding Conplast SP430 to the fresh concrete to know the effect of these

materials on the properties of the concrete so produced.

1.3 AIM AND OBJECTIVES OF RESEARCH

The aim of this study is to give the effect of the addition of fly ash as a partial replacement of

cement and conplast SP430 as a super plasticizer on the properties of the concrete made.

OBJECTIVES

The objectives of this study are to;

i. evaluate the compressive strength of concrete made from cement as the binder, and

that made from the partial replacement with 5%, 10%, 15%, 20%, 25% and 30% of

fly ash by percentage of cement and adding conplast SP430 in percentages of 0.5%,

1.0%, 1.5% and 2.0% by the weight of cement.

ii. evaluate the effect of adding fly ash as partial replacement of cement on the

consistency;

iii. determine the effect of adding fly ash as a partial replacement of cement and conplast

SP430 in percentage by mass of water to cement ratio on the workability of concrete.

1.4 SCOPE OF WORK

This work consists of making concrete by buying the fine aggregate that is sand, the coarse

aggregate is also bought also with the cement. The fly ash is gotten from the producer. The

concrete is made in a cubic mould of size 150mm × 150mm ×150mm dimension. The concrete is

first made without the addition of fly ash that is the control sample, the concrete is also made

with replacement of the cement content partly with 5%, 10%, 15%, 20%, 25% and 30% of fly

ash by weight of cement. Concrete is also made by adding Conplast SP430 a super-plasticizer in

percentages of 0.5%, 1.0%, 1.5% and 2.0% by weight of cement with the percentages of fly ash

added to cement. Preliminary tests are done on the materials, slump test will be done on all the

fresh concrete made. The crushing tests are then made on the hardened concrete. The results

gotten are then compared with that from the control and conclusions are then drawn and made.

1.5 JUSTIFICATION

In the construction of civil engineering structures, the use of cement as the main cementing

material had actually resulted in the high cost of such structures, it become expedient that the use

of other materials that will be used as alternative of cement.

This study is aimed at providing an alternative to the use of cement that is not expensive and

easily gotten. The strength of concrete made by the use of cement alone is studied and those

made from the partial replacement of 5%, 10%, 15%, 20%, 25% and 30% of fly ash is compared

after curing for a period of 7 days, 14 days, 21 days and 28 days. More so, the strength is also

compared with adding Conplast SP430 in percentages of 0.5%, 1.0%, 1.5% and 2.0% by the

weight of cement with the percentages of fly ash to cement. Also, the workability of concrete

made by cement alone is compared with that of the partial replacement with fly ash.

CHAPTER TWO

LITERATURE REVIEW

2.1 THEORETICAL BACKGROUND

That concrete is a common structural material is, no doubt, well known. But, how common it is,

and how much a part of our daily lives it plays, is perhaps not well known — or rather, not often

realized. Structural concrete is used extensively in the construction of various kinds of buildings,

stadia, auditoria, pavements, bridges, piers, breakwaters, berthing structures, dams, waterways,

pipes, water tanks, swimming pools, cooling towers, bunkers and silos, chimneys,

communication towers, tunnels, etc. Concrete has been in use as a building material for more

than a hundred and fifty years. Its success and popularity may be largely attributed to:

(1) durability under hostile environments (including resistance to water),

(2) ease with which it can be cast into a variety of shapes and sizes, and

(3) its relative economy and easy availability.

The main strength of concrete lies in its compression-bearing ability, which surpasses that of

traditional materials like brick and stone masonry.

Concrete is a non – homogeneous manufactured stone composed of graded, granular inert

materials which are held together by the action of cement and water. The inert materials usually

consist of gravel or large particles of crushed stone, and sand or pulverized stone. Manufactured

lightweight materials are also used. The inert materials are called aggregates. The large particles

are called coarse aggregates and the small particle are called fine aggregates (Everard and

Tanner, 1996).

Concrete is a stone – like material obtained by permitting a carefully proportioned mixture of

cement, sand and gravel or other aggregate, and water to harden in forms of the shape and

dimensions of the desired structure. The bulk of the material consist of fine and coarse aggregate.

Cement and water interact chemically to bind the aggregate particle into a solid mass. Additional

water, over and above that needed for this chemical reaction, is necessary to give the mixture the

workability that enables it to fill the forms (Pillai and Mennon, 2003). Concretes with a wide

range of properties can be obtained by appropriate adjustment of the proportions of the

constituents materials. Special cements (such as high early strength cements), special aggregates

(such as various lightweight or heavyweight aggregates) admixtures (such as plasticizers, air –

entraining agents, silica fume and fly ash) and special curing methods (such as steam – curing)

permit an even wider variety of properties to be obtained. Concrete may be either good or bad

concrete. Good concrete is one that has the desired qualities of strength, impermeability,

durability, etc., in the hardened state. To achieve this, the concrete has to be ‘satisfactory’ in the

fresh state (which includes mixing, handling, placing, compacting and curing). Broadly, this

means that the mix must be of the right proportions, and must be cohesive enough to be

transported and placed without segregation by the means available, and its consistency must be

such that it is workable and can be compacted by the means that are actually available for the job

(Nilson et al, 2010).

This research work examines the partial replacement of cement with percentages of fly ash as

additives on the properties of concrete produced. This will show if the addition of fly ash by

percentages will enhance the strength of the concrete produced thereby indicating the use of fly

ash as an admixture with a positive impact on the concrete.

2.2 COMPONENTS OF CONCRETE

2.2.1 CEMENT

Cement is produced by burning together, in a definite proportion a mixture of silicious

(containing silica), argillaceous (containing alumina) and calcareous (containing lime) material

in partial fusion, at a temperature of 1400°C to 1450°C. A cementitious material is one that has

the adhesive and cohesive properties necessary to bond inert aggregates into a solid mass of

adequate strength and durability. The cement used in the making of concrete are called hydraulic

cement, because they have the tendency of reacting chemically with water in an exothermic (heat

generating) process termed hydration that results in water – resistant products. As a result of

hydration, setting and hardening of cement takes place. Cement suitable for concrete are ordinary

and rapid – hardening Portland cements, Portland blast – furnace cement, low – heat Portland

cement, and high – alumina cement. The cement to be used for this work is the Ordinary

Portland Cement (OPC). The Ordinary Portland cement is the basic Portland cement, with an

initial setting time that must be less than 45minutes and the final setting time not more than

10hours, (Reynolds and Steedman, 2005).

2.2.2 AGGREGATE

Aggregate usually constitute between 50 and 80% of the volume of conventional concrete and

may thus greatly influence its properties. Aggregate contributes significantly to the structural

performance of concrete, especially strength, durability and volume stability. Aggregates should

not contain any constituents which affects the hardening of the cement and durability of the

hardened concrete adversely. Aggregate is formed from natural sources by the process of

weathering and abrasion, or by artificially crushing a larger parent (rock) mass. Aggregates are

classified as

i. fine aggregate and

ii. coarse aggregate.

Fine aggregates have particle sizes between 0.075mm and 4.75mm. Coarse aggregate have

particle sizes larger than 4.75mm. Sand taken from river beds and pits is normally used as fine

aggregate, after it is cleaned and rendered free from silt, clay and other impurities; stone (quarry)

dust is sometimes used as a partial replacement for sand. Gravel and crushed rock are normally

used as coarse aggregate.

Fine aggregate (sand) and coarse aggregate (stone) must be clean, inert, hard, non – porous and

free from excessive quantities of dust, laminated particles and splinters.

GRADING OF AGGREGATE

Grading is the particle size distribution of aggregate; it is measured by sieve analysis and is

generally described by means of a grading curve, which depicts the ‘cumulative percentage

passing’ against the standard sieve sizes.

The grading (as well as the type and size) of aggregate is a major factor which influences the

workability of fresh concrete, and its consequent degree of compaction. This is of extreme

importance with regard to the quality of hardened concrete, because incomplete compaction

results in voids, thereby lowering the density of the concrete and preventing it from attaining its

full compressive strength capability [Fig. 2.1]; furthermore, the impermeability and durability

characteristics get adversely affected. It is seen from Fig. 2.1 that as little as 5 percent of voids

can lower the strength by as much as 32 percent (Pillai and Mennon, 2008)

Fig. 2.1 Relation between density ratio and strength ratio

2.2.3 WATER

Water has a significant role to play in the making of concrete – in mixing of fresh concrete and

in curing of hardened concrete. To ensure proper strength development and durability of

concrete, it is necessary that the water used for mixing and curing is free from impurities such as

oil, acids, salts, sugar and organic materials.

Water that is fit for human consumption (that is, potable water) is generally considered to be

suitable for concreting. When the potability of the water is suspected, it is advisable to perform a

chemical analysis of the water. Sea water is particularly unsuitable for mixing or curing of

concrete.

WATER CONTENT AND WORKABILITY OF CONCRETE

The water in a concrete mix is not only for hydration with cement, but also for workability.

Workability is defined as the property of the fresh mixed concrete which determines the ease and

homogeneity with which it can be mixed, placed, compacted and finished. The main factor that

influences workability is the water content, as the ‘inter-particle lubrication’ is enhanced by the

addition of water. The amount of water required for the lubrication depends on the aggregate

type, texture and grading. Water content in a mix is also related to the fineness of cement, that is,

the finer the cement, the greater the need for water – for hydration as well as workability.

Workability is required to facilitate full placement in the formwork and full compaction,

minimizing the voids in concrete. The addition of water provides for better cohesion of the mix

and better compaction, and causes the air bubbles to get expelled. The workability is checked by

one of the standard tests:

i. slump test

ii. compacting factor test

iii. vebe – consistometer test.

2.2.4 ADMIXTURES

In addition to the main components of concretes, admixtures are often added to improve concrete

performance. There are admixtures to accelerate or retard setting and hardening, to improve

workability, to increase strength, to improve durability, to decrease permeability, and to impart

other properties. The code recommends, “The workability, compressive strength and the slump

loss of concrete with and without the use of admixtures shall be established during the trial mixes

before the use of admixtures”. Also, the use of admixtures should not impair durability and

increase the risk of corrosion to reinforcement.

Admixtures are either ‘chemical’ (liquid) or ‘mineral’ (fine granular) in form. They are now

being increasingly used in concrete production, particularly when there is an emphasis on either

‘high strength’ or ‘high performance’ (durability). The use of chemical admixtures is inevitable

in the production of ready-mixed concrete, which involves transportation over large distances of

fresh concrete that is manufactured under controlled conditions at a batching plant.

There are different types of chemical admixtures, of which some of the more important chemical

admixtures are briefly described as follows:

a) Accelerators: chemicals (notably, calcium chloride) to accelerate the hardening or the

development of early strength of concrete; these are generally used when urgent repairs

are undertaken, or while concreting in cold weather;

b) Retarders: chemicals (including sugar) to retard the setting of concrete, and thereby also

to reduce the generation of heat; these are generally used in hot weather concreting and in

ready-mixed concrete;

c) Water-reducers (or plasticizers): chemicals to improve plasticity in the fresh concrete;

these are mainly used for achieving higher strength by reducing the water-cement ratio;

or for improving workability (for a given water-cement ratio) to facilitate placement of

concrete in locations that are not easily accessible;

d) Super-plasticizers (or high-range water-reducers): chemicals that have higher dosage

levels and are supposedly superior to conventional water-reducers; they are used for the

same purposes as water-reducers, viz. to produce high-strength concrete or to produce

‘flowing’ concrete;

e) Air-entraining agents: organic compounds (such as animal/vegetable fats and oils, wood

resins) which introduce discrete and microscopic air bubble cavities that occupy up to 5

percent of the volume of concrete; these are mainly used for protecting concrete from

damage due to alternate freezing and thawing;

f) Bonding admixtures: polymer emulsions (latexes) to improve the adherence of fresh

concrete to (old) hardened concrete; they are ideally suited for repair work.

Mineral admixtures are used either as partial replacement of cement or in combination with

cement, at the time of mixing, in order to modify the properties of concrete or achieve economy.

Some of the more important mineral admixtures are described briefly:

Pozzolanas are materials containing amorphous silica, which, in finely divided form and in the

presence of water, chemically react with calcium hydroxide at ordinary temperatures to form

compounds possessing cementitious properties; the Code permits their use, provided uniform

blending with cement is ensured. Some mineral admixtures are

a) fly ash: ash precipitated electrostatically or mechanically from exhaust gases in coal-

fired power plants, conforming to Grade 1 of IS 3812;

b) ground granulated blast-furnace slag, conforming to IS 12089, has good pozzolanic

properties, and produces concrete with improved resistance to chemical attack;

c) silica fume (or micro silica), obtained as a by-product of the silicon industry, is found to

be not only pozzolanic in character but also capable of producing very dense concrete,

and is finding increasing use in the production of high-strength and high-performance

concrete;

d) rice husk ash: produced by burning rice husk at controlled temperatures;

e) metakaoline: obtained by calcination of kaolinitic clay(a natural pozzolana), followed by

grinding;

2.2.4.1 FLY ASH

Fly ash is the finely divided residue that results from the combustion of pulverized coal and is

transported from the combustion chamber by exhaust gases. Fly ash is a good pozzolanic mineral

admixture, which can replace large quantity of cement in the concrete. Fly ash is primarily

silicate glass containing silica, alumina, iron, and calcium. Minor constituents are magnesium,

sulfur, sodium, potassium, and carbon. The positive effects of using fly ash in concrete are better

quality of concrete, eco-friendly and preservation of resources. Fly ash utilization, especially in

concrete, has significant environmental benefits including:

i. increasing the life of concrete roads and structures by improving concrete durability,

ii. net reduction in energy use and greenhouse gas and other adverse air emissions when fly

ash is used to replace or displace manufactured cement,

iii. reduction in amount of coal combustion products that must be disposed in landfills, and

iv. conservation of other natural resources and materials.

The four most relevant characteristics of fly ash for use in concrete are loss on ignition (LOI),

fineness, chemical composition and uniformity.

LOI is a measurement of unburned carbon (coal) remaining in the ash and is a critical

characteristic of fly ash, especially for concrete applications. High carbon levels, the type of

carbon (i.e., activated), the interaction of soluble ions in fly ash, and the variability of carbon

content can result in significant air-entrainment problems in fresh concrete and can adversely

affect the durability of concrete. AASHTO and ASTM specify limits for LOI. However, some

state transportation departments will specify a lower level for LOI. Carbon can also be removed

from fly ash. Some fly ash uses are not affected by the LOI. Filler in asphalt, flow-able fill, and

structural fills can accept fly ash with elevated carbon contents.

Fineness of fly ash is most closely related to the operating condition of the coal crushers and the

grind-ability of the coal itself. For fly ash use in concrete applications, fineness is defined as the

percent by weight of the material retained on the 0.044 mm. A coarser gradation can result in a

less reactive ash and could contain higher carbon contents. Fly ash can be processed by screening

or air classification to improve its fineness and reactivity.

Some non-concrete applications, such as structural fills are not affected by fly ash fineness.

However, other applications such as asphalt filler, are greatly dependent on the fly ash fineness

and its particle size distribution.

Chemical composition of fly ash relates directly to the mineral chemistry of the parent coal and

any additional fuels or additives used in the combustion or post-combustion processes. The

pollution control technology that is used can also affect the chemical composition of the fly ash.

Electric generating stations burn large volumes of coal from multiple sources. Coals may be

blended to maximize generation efficiency or to improve the station environmental performance.

The chemistry of the fly ash is constantly tested and evaluated for specific use applications.

Some stations selectively burn specific coals or modify their additives formulation to avoid

degrading the ash quality or to impart a desired fly ash chemistry and characteristics.

Uniformity of fly ash characteristics from shipment to shipment is imperative in order to supply

a consistent product. Fly ash chemistry and characteristics are typically known in advance so

concrete mixes are designed and tested for performance.

The use of fly ash in Portland cement concrete has many benefits and improves concrete

performance in both the fresh and hardened state. Fly ash use in concrete improves the

workability of plastic concrete, and the strength and durability of hardened concrete. Fly ash use

is also cost effective. When fly ash is added to concrete, the amount of Portland cement may be

reduced.

The benefits of using fly ash in concrete include the following (Klieger et al. 1994):

Improved workability,

Lower heat of hydration,

Lower cost concrete,

Improved resistance to sulfate attack,

Improved resistance to alkali-silica reaction,

Higher long-term strength,

Opportunity for higher strength concrete,

Equal or increased freeze thaw durability,

Lower shrinkage characteristics, and

Lower porosity and improved impermeability.

CHEMICAL COMPOSITION OF FLY ASH

The chemical composition present in fly ash are silicon dioxide, SiO2, aluminium oxide, Al2O3,

ferric oxide. Fe2O3, sulfur trioxide, SO3, calcium oxide, CaO, magnesium oxide, MgO, titanium

dioxide TiO2, potassium oxide K2O, and sodium oxide Na2O.

In general, depending on the chemical composition, fly ash can be classified as

i. Class F or

ii. Class C.

Class C fly ash has higher amount of CaO, so it possesses more cementing characteristics and is

less pozzolanic than Class F fly ash. ASTM C 618 states that Class F fly ash is “normally

produced from burning anthracite or bituminous coal”, while Class C fly ash is “normally

produced from lignite and sub-bituminous coal” ( ASTM). Class F fly ash is mostly composed of

silicate glass containing aluminum, iron and alkalis. Class F fly ash is available in the largest

quantities. Class F is generally low in lime, usually under 15%, the carbon content is usually less

than 5% and contains a greater combination of silica, alumina and iron (greater than 70%) than

Class C fly ash. Class C fly ash normally comes from coals which may produce an ash with

higher lime content generally more than 15% often as high as 30% and the carbon content is less

than 2%. Elevated CaO may give Class C unique self-hardening characteristics.

2.2.4.2 SUPER – PLASTICIZERS

The super – plasticizer that is used for this work is Conplast SP430. It is a high range water

reducing admixture. Conplast SP430 is based on Sulphonated Napthalene Polymers and is

supplied as a brown liquid instantly dispersible in water. Conplast SP430 has been specially

formulated to give high water reductions up to 25% without loss of workability or to produce

high quality concrete of reduced permeability.

The properties of Conplast SP430 are as seen below

i. Specific gravity of 1.20 to 1.22 at 30°C.

ii. It has no chloride content.

iii. It has an approximate of 1% air entrained.

iv. Compatibility: Can be used with all types of cements except high alumina cement.

Conplast SP430 is compatible with other types of Fosroc admixtures when added

separately to the mix. Site trials should be carried out to optimize dosages.

v. Workability: Can be used to produce flowing concrete that requires no compaction. Some

minor adjustments may be required to produce high workable mix without segregation.

vi. Cohesion: Cohesion is improved due to dispersion of cement particles thus minimizing

segregation and improving surface finish.

vii. Compressive strength: Early strength is increased up to 40 to 50% if water reduction is

taken advantage of. Generally, there is improvement in strength up to 20% depending

upon W/C ratio and other mix parameters.

viii. Durability: Reduction in W/C ratio enables increase in density and impermeability thus

enhancing durability of concrete.

2.3 PRESENT STATUS OF RESEARCH

Nath and Sarker (2011) observed that the utilization of fly ash as a supplementary cementitious

material adds sustainability to concrete by reducing the CO2 emission of cement production. The

positive effects of fly ash as a partial replacement of cement on the durability of concrete are

recognized through numerous researches; however, the extent of improvement depends on the

properties of fly ash. In this study, durability properties of high strength concrete utilizing high

volume Class F fly ash sourced from Western Australia have been investigated. Concrete

mixtures with fly ash as 30% and 40% of total binder were used to cast the test specimens. The

compressive strength, drying shrinkage, sorptivity and rapid chloride permeability of the fly ash

and control concrete specimens were determined. The 28 days compressive strength of the

concrete mixtures varied from 65 to 85 MPa. The fly ash concrete samples showed less drying

shrinkage than the control concrete samples when designed for the same 28-day compressive

strength of the control concrete. Inclusion of fly ash reduced sorptivity and chloride ion

permeation significantly at 28 days and reduced further at 6 months. In general, incorporation of

fly ash as partial replacement of cement improved the durability properties of concrete.

Heba (2011), presented an experimental study on self-compacting concrete (SCC) with two

cement content. The work involves three types of mixes, the first consisted of different

percentages of fly ash (FA), the second uses different percentages of silica fume (SF), and the

third uses a mixture of FA and SF. After each mix preparation, nine cylinder specimens are cast

and cured. Three specimens are cured in air for 28 days, three specimens are cured in water for 7

days, and three specimens are left in air for 28 days. The slump and V-funnel test are carried out

on the fresh SCC and concrete compressive strength values are determined. The results show that

SCC with 15% of SF gives higher values of compressive strength than those with 30% of FA and

water cured specimens for 28 days give the highest values of compressive strength.

Alvin et al (2014) showed that in India, currently a large amount of fly ash is generated mainly in

thermal power plants with an imperative blow on environment and living organism. The use of

fly ash in concrete can reduce the consumption of natural resources and also diminishes the

effect of pollutant in environment. In recent studies, many researchers found that the use of

additional cementitious materials likes fly ash in concrete is economical and reliable. This

investigation is a part of experimental program carried out to study the utilization of non-

conventional building material (fly ash) for development of new materials and technologies. It is

aimed at materials which can fulfil the expectations of the construction industry in different

areas. In this study, cement has been replaced by fly ash accordingly in the range of 0% (without

fly ash), 10%, 20%, 30%, 40%, 50% and 60% by weight of cement for M-25 mix with 0.46

water cement ratio. Concrete mixtures were produced, tested and compared in terms of

compressive strength. It was observed that 20% replacement Portland Pozzolana Cement (PPC)

by fly ash strength increased marginally (1.9% to 3.2%) at 28days and 56 days respectively. It

was also observed that up to 30% replacement of PPC by fly ash strength is almost equal to

referral concrete after 56 days. PPC gained strength after the 56 days curing because of slow

hydration process.

Patil et al (2012), investigated that fly ash, a waste generated by thermal power plants is as such

a big environmental concern. The investigation reported in this paper is carried out to study the

utilization of fly ash in cement concrete as a partial replacement of cement as well as an additive

so as to provide an environmentally consistent way of its disposal and reuse. This work is a case

study for Deep Nagar thermal power plant of Jalgaon District in MS. The cement in concrete

matrix is replaced from 5% to 25% by step in steps of 5%. It is observed that replacement of

cement in any proportion lowers the compressive strength of concrete as well as delays its

hardening. This provides an environmental friendly method of Deep Nagar fly ash disposal.

Semsi and Hasan (2012) reviewed on the effects of fly ash fineness on the compressive and

splitting tensile strength of the concretes. A fly ash of lignite origin with Blaine fineness of 2351

cm2/g was ground in a ball mill. As a consequence of the grinding process, fly ashes with

fineness of 3849 cm2/g and 5239 cm2/g were obtained. Fly ashes with three different fineness

were used instead of cement of 0%, 5%, 10%, and 15% and ten different types of concrete

mixture were produced. In the concrete mixtures, the dosage of binder and water/cement ratio

were fixed at 350kg/m3 and 0.50, respectively. Slump values for the concretes were adjusted to

be 100 ± 20 mm. Cubic samples were cast with edges of 100 mm. The specimens were cured in

water at 20◦C. At the end of curing process, compressive and splitting tensile strengths of the

concrete samples were determined at 7, 28, 56, 90, 120 and 180 days. It was observed that

compressive and splitting tensile strength of the concretes was affected by fineness of fly ash in

short-and long-terms. It was found that compressive and tensile strength of the concretes

increased as fly ash fineness increased. It was concluded that Blaine fineness value should be

above 3849 cm2/g fineness of fly ash to have positive impact on mechanical properties of

concrete. The effects of fly ash fineness on the compressive and splitting tensile strength of the

concretes were remarkably seen in the fly ash with FAC code with fineness of 5235 cm2/g.

Chindaprasirt et al (2005) studied the effects of the fineness of fly ash on compressive strength

and porosity of the mortar, and size of spaces in hardened cement paste. In that study, fly ashes

of type F were ground and classified into 2 fineness types. In preparation of mortar mixtures,

cement was replaced with two types of fly ashes having different fineness, at replacement levels

of 20% and 40%. As a result of the tests performed, it was seen that the compressive strength of

the mortar made by using classified fly ash was higher than those made by using unclassified fly

ash. However, it was noted that the compressive strength of the mortar with fly ashes was lower

than control mortar made with Portland cement in all time periods. It was seen that the grinded

ash with high fineness provided higher early strength than the mortars produced with coarse

ashes used without grinding. The authors concluded that finer fly ash made the hardened cement

paste more compact and denser, and thus its contribution to the strength was higher compared to

the original fly ash.

Tarun et al (2002) investigated on the effects of the source and amount of fly ash on abrasion

resistance of concrete. A reference concrete was proportioned to have a 28-day age strength of

41 MPa. Three sources of Class C fly ash were used in this research. From each source, three

levels of fly ash to total cementitious materials content 40%, 50%, and 60% were used in

producing the concrete mixtures. The water to cementitious materials ratio was kept constant at

0.30 for all mixtures. An accelerated abrasion testing method, a modified ASTM C 944 test, was

used to measure the abrasion resistance of this high-strength concrete. The effects of both the

source and the amount of fly ash on abrasion resistance of concrete were noticeable. All concrete

mixtures with and without fly ash exhibited high abrasion resistance in accordance with the

ASTM requirement. Concrete abrasion resistance was not greatly influenced by inclusion of

Class C fly ash up to 40% of total cementitious materials. However, a slight decrease in abrasion

resistance of high-volume fly ash (HVFA) concrete especially at fly ash content above 50% was

noted as compared to the reference mixture without fly ash.

Aman et al (2013) studied on the effect on strength and mechanical properties of cement

concrete by using fly ash. The utilization of fly-ash in concrete as partial replacement of cement

is gaining immense importance today, mainly on account of the improvement in the long term

durability of concrete combined with ecological benefits. Technological improvements in

thermal power plant operations and fly-ash collection systems have resulted in improving the

consistency of fly-ash. To study the effect of partial replacement of cement by fly-ash , studies

have been conducted on concrete mixes with 300 to 500 kg/cum cementious materials at 20%,

40%, 60% replacement levels. In this paper the effect of fly-ash on workability, setting time,

density, air content, compressive strength, modulus of elasticity are studied Based on this study

compressive strength v/s W/C curves have been plotted so that concrete mix of grades M 15, M

20,M 25 with difference percentage of fly-ash can be directly designed.

Shantmurti (2014) showed that although the ordinary Portland cement (OPC) is one of the main

ingredients used for the production of concrete. Unfortunately production of cement involves

emission of large amount of carbon dioxide gas into atmosphere, a major contributor for

greenhouse effect and the global warming, hence it is inevitable either to search for another

material or partially replace it by some other material. The search of any other such material

which can be used as an alternative for cement should lead to global sustainable development

and lowest possible environmental impact. Concrete property can be maintained with advance

mineral admixtures such as fly ash as partial replacement of cement 0 to 30%. Compressive

strength of concrete with different dosage of fly ash was studied as partial replacement of

cement. From the experimental investigations, it has been observed that, the optimum

replacement of fly ash to cement without changing much compressive strength is 10%.

Wankhede and Fulari (2014) observed the effect of fly Ash on properties of concrete. In the

present study, use of fly ash in concrete imparts several environmental benefits and thus it is

ecofriendly. It saves the cement requirement for the same strength thus saving of raw materials

such as limestone, coal etc required for manufacture of cement. Fly ash is pozzolanic material

and it improves the properties of concrete like compressive strength and durability. The results

obtained are discussed and compared with the available literature.

Malhotra (1990), studied in detail the properties of concrete with a wide range of Canadian fly

ashes at 58% of the total cementitious materials. These concretes were tested for compressive

strength, creep strain and resistance to chloride ion penetration at various ages up to one year.

Joshi et al (1994), indicated that with fly ash replacement level up to 50% by cement weight,

concrete with 28 days strength ranging from 40 to 60 MPa and with adequate durability can be

produced with cost saving of 16% by 50% replacement level.

Sarath et al (2011) observed that the utilization of fly ash in concrete as partial replacement of

cement is gaining immense importance today, mainly on account of the improvement of the long

term durability of concrete combined with ecological benefits. Technological improvements in

thermal power plants operation and fly ash collection systems have resulted in improving the

consistency of fly ash. To study the effect partial replacement of cement by fly ash, studies have

been conducted on concrete mixes with 300 to 500 kg/m3, cementitious material at 20%, 30%,

40% and 50% replacement level. In their work the effect of fly ash on workability, setting time,

density, air-content, and compressive strength, modulus of elasticity, shrinkage and permeability

by Rapid Chloride Permeability Test (RCPT) are studied.

Muntadher and Vikas (2013) presented the result of an experimental investigation carried out to

evaluate the mechanical properties of concrete with steel fibre and steel fibre fly ash in which

Portland pozzolana cement was partially replaced with fly ash by weight. The experimental

investigation carried out on steel fibres concrete up to a total fibre volume fraction of 0.5%, 1%

and 1.5% and fly ash in which Portland pozzolana cement (PPC) was partially replaced with

30% fly ash. The mechanical properties, compressive strength and splitting tensile strength were

studied for concrete prepared. Compressive strength and splitting tensile strength were

determined at 7, 28 and, 56 days. The laboratory results showed that addition of steel fibres

reinforced fly ash into

PPC concrete decreases the strength properties. While the results showed that steel fibres

addition into PPC concrete improve the strength properties.

Salahaldein (2009), studied on the effects of mineral admixtures on workability and compressive

strength of concretes containing fly ash (FA) were experimentally investigated. The research

variables included ordinary Portland cement (OPC) and mineral admixtures content was used as

a partial cement replacement. They were incorporated into concrete at the levels of 10%, 20%

and 30% for fly ash by weight of cement. Water-cement ratio of 0.67 was used and tests were

carried out at 7 and 28 days. From the tests, the lowest measured workability values were for the

10% fly ash mix. The highest compressive strength of concretes determined was for 10% fly ash

mix with ordinary Portland cement and was reduced with the increase in the replacement ratios

for other mineral admixtures than ordinary Portland cement concrete. The main objective of this

research was to determine the workability and compressive strength of concrete containing fly

ash to achieve the best concrete mixture having high workability and compressive strength. The

results were compared to the control concrete; ordinary Portland cement concrete without

admixtures. The optimum cement replacement by FA in this experiment was 10%. The

knowledge on the strength and workability of concrete containing fly ash could be beneficial in

the utilization of these waste materials in concrete work.

Banchhor and Krishnan (2013) presented the results of an experimental investigation that was

carried out to evaluate the effectiveness of key performance characteristics of concrete

incorporating fly ash by means of, inter-ground PPC and site mixing OPC and fly ash. A host of

properties of concrete were studied. Both drum mixer and pan mixer were used in the stud to

evaluate the mixing efficiency. The results of investigations indicate that the performance of

concrete using Fly Ash is better than the OPC concrete, especially with respect to durability

indicator due to pozzolanic action of fly ash leading to pore refinement and denser concrete

matrix The beneficial effects of fly ash are seen more pronounced in case of factory-ground

Portland Pozzolona Cement (PPC) than site mixing of fly ash with OPC under normal Indian

construction site conditions. The inter-grinding of fly ash with clinker and gypsum maximizes

the pozzolanic potential of fly ash with more consistent product with good control on variability,

leading to a better performance of PPC concrete.

Kazberuk and Lelusz (2007) generated mathematical models to predict the development of

compressive strength of concrete with fly ash replacement percentages up to 30 %. Strength of

concrete with different types of cement (CEM I 42.5, CEM I 32.5, CEM III 32.5), after 2, 28, 90,

180 days of curing, have been analyzed to evaluate the effect of addition content, the time of

curing and the type of cement on the compressive strength changes. The adequacy of equations

obtained was verified using statistical methods. The test results of selected properties of binders

and hardened concrete with fly ash are also included. The analysis showed that concrete with fly

ash is characterized by advantageous applicable qualities.

Maroliya (2012) showed the results of test conducted on concrete in the presence of plasticizers

and super plasticizers. The objective was to observe the change in density of concrete and loss of

workability under the influence of plasticizers and super plasticizers at various dosages level.

The result of the treated mix was compared with the control mix (mix without admixture).

Observations were made on solid phases of concrete, to note the variation in density at constant

and reduce water cement ratio. From the experience and knowledge gained from this course of

study both, plasticizers and super- plasticizers not only improved workability at constant water

cement ratio but considerably enhanced the density at reduce water-cement ratio however loss in

slump observed.

Shanmugapriya1 and Uma (2012) showed that sand is the one of main constituents of concrete

making which is about 35% of volume of concrete used in construction industry. Natural sand is

mainly excavated from river beds and always contain high percentage of in organic materials,

chlorides, sulphates, silt and clay that adversely affect the strength, durability of concrete &

reinforcing steel there by reducing the life of structure, when concrete is used for buildings in

aggressive environments, marine structures, nuclear structures, tunnels, precast units, etc. Fine

particles below 600 microns must be at least 30 % to 50% for making concrete will give good

results 1. Normally particles are not present in river sand up to required quantity. Digging sand,

from river bed in excess quantity is hazardous to environment. The deep pits dug in the river bed,

affects the ground water level. Erosion of nearby land is also due to excessive sand lifting. In

order to fulfill the requirement of fine aggregate, some alternative material must be found. The

cheapest and the easiest way of getting substitute for natural sand is by crushing natural stone to

get artificial sand of desired size and grade which would be free from all impurities is known as

Manufactured sand. Concrete made with crushed stone dust as replacement of natural sand in

concrete can attain the same compressive strength, comparable tensile strength, modulus of

rupture and lower degree of shrinkage as the control concrete2. From Literature Review it is

observed that compressive and split tensile strength of M30 grade concrete increased by

replacing 30% of natural sand with M-Sand. The super plasticizer Conplast SP430 was used as

chemical admixture. Conplast SP430 is based on Sulphonated Naphthalene Polymers and it is a

brown liquid instantly dispersible in water. It has been specially formulated to give high water

reductions up to 25% without loss of workability and produce high quality concrete to enhance

strength and durability with low binder ratio 0.26 to 0.4. Increasing dosage of super plasticizer

by weight of binder (Cement and Silica fume) improved the performance of concrete and

contribute more to improvement of its workability properties as well as mechanical properties

with reduced W/B ratio

Borsoi et al (2011) manufactured four concretes all with Portland cement at a given slump of

220-240 mm: a) control mixture without any chemical admixture; b) concrete with a

policarboxylate based super plasticizer at the same water-cement ratio as that of the control

concrete; c) concrete containing a shrinkage-reducing admixture (SRA) at the same composition

as that of the control concrete; d) concrete with both super plasticizer and SRA at the same

water-cement ratio as that of the control mixture.Concretes were exposed to a dry environment

with a relative humidity of 50% after a wet curing of 2 days. Measurements of drying shrinkage

were carried out as a function of time up to 1 year. In the super plasticizer mixtures both cement

and water were reduced at given water-cement ratio and slump. The drying shrinkage at a given

time of the super plasticized concrete decreased by 15-20 % with respect to that of the control

concrete due to the higher aggregate-cement ratio. In the presence of SRA the drying shrinkage

was reduced by 20-25 % with respect of that of the control mixture at the same composition of

the concrete mixture. In the presence of both super plasticizer and SRA the drying shrinkage

decreased by 30-35 % with respect to the control mixture at given water-cement ratio and slump.

Because of the decrease in the drying shrinkage caused by the chemical admixtures, the cracking

in restrained slabs was significantly reduced in terms of number and maximum width of cracks.

Uniyal (2015), showed that self-compacting concrete is a high- performance concrete that flows

under its self-weight with adequately filling all the voids without any segregation or bleeding. It

is a revolutionary development in the area of concrete admixtures. In this paper effort has been

made to present the effect of temperature on compressive strength of self-compacting concrete

produced by replacing ordinary Portland cement with 15% fly ash and then treated water

quenched. Compressive strength of concrete is the major property which identifies the quality of

concrete produced. Generally the compressive strength test is performed on concrete samples at

room temperature to determine the developed strength of concrete. In order to study the effects

of high temperatures on compressive strength of SCC, cubical specimens (100x100x100 mm)

were heated at high temperatures (150˚C, 200˚C, 250˚C and 300˚C) for varying exposure

duration (112

, 212

and 3 hours) . The results obtained were compared with the corresponding

properties of NVC (Normally Vibrated Concrete).

Pradhan and Dutta (2013), investigated on the production of tailor made high strength and high

performance concrete are made by incorporating silica fume into the normal concrete and it is a

routine one in the present days. The mix proportioning is intricate and the design parameters are

increased due to the incorporation of silica fume in conventional concrete. The aim of this paper

is to look into the different mechanical properties like compressive strength, compacting factor,

slump of concrete incorporating silica fume. In this present paper concrete incorporating silica

fume are cast for 5 (five) mixes to perform experiments. Different percentages of silica fume are

used for cement replacement in order to carry out these experiments at a single fixed water-

cementitious materials ratio keeping other mix design parameters constant. The cement

replacement level by silica fume was 0%, 5%, 10%, 15% and 20% for a constant water-

cementitious materials (water/cement) ratio for 0.50. 100 and 150 mm cubes are used to

determine the compressive strengths for all mixes at the age levels of 24 hours, 7 and 28 days.

Besides the compressive strengths other properties like compacting factor, slump of concrete are

also determined for five mixes of concrete.

Darshan and Gowda (2014), presented an investigation on the effect of ground granulated blast

furnace slag (GGBS) as a replacement of cement. The study also intended to quantify the amount

of Ground granulated blast furnace slag (GGBS) to be added to the concrete according to the

value of concrete properties Measured. Here Portland cement (PC) is replaced by 20-55% with

an interval of 5% by GGBS. The water/Portland cement ratio is kept constant throughout the

investigation as 0.45. Super plasticizer known as Conplast SP430 is used. Since there is no

standard method of mix design is available for SCC. Hence the mix proportion is obtained as per

the guidelines given by European Federation of producers and contractors of special products for

structure (EFNARC). This paper presents an experimental investigation on strength aspects like

compressive, flexural and split tensile strength and the workability tests. The result of fresh

property test satisfies the limits specified by EFNARC. Results suggest that as much of 30% of

cement can be replaced without any significant consequences on the concrete produced.

Manoharan et al (2009), showed that water reducing admixture is widely used in concretes with

less water-cement ratio, to improve some properties like strength and workability. In addition,

this admixture has effect on corrosion resistance of embedded re-bars in concrete. In this work,

the corrosion rate of mild steel rod, CTD (Cold Twisted Deformed) rod and TMT (Thermo

Mechanically Treated) rod were observed by adding water reducing admixture in M25 concrete

mix. By varying the percentage of admixture, the study was carried out for a period of 14

months. The corrosion rates were measured at different intervals by conducting electrochemical

tests like ACI test, LPR test, and OCP test and by weight loss test (gravimetric method). In most

of the time and cases, the corrosion rate was found to be less for 0.5% of water reducing

admixture. Corrosion resistance of TMT rod is better than other rods like mild steel and CTD

rods.

Dumme (2014), investigated on the use of mineral and chemical admixtures in concrete is a

common solution to achieve full compaction particularly where reinforcement congestion and

shortage of skilled workers. The past researchers have been underscored the use of mineral and

chemical admixtures imparts the desirable properties to concrete in both fresh and hardened

state. This paper has been made an attempt to study the influence of super plasticizer dose of

0.25, 0.30 and 0.35 percentage on performance of Self-Compacting Concrete containing 10% fly

ash of cement content. The experimental tests for fresh and hardened properties of Self-

Compacting Concrete for three mixes of M20 grade are studied and the results are compared

with normal vibrated concrete. The tests considered for study are, slump test, compaction factor

test, unit weight and compressive strength test The results show that for the constant water

cement ratio, increase of superplasticizer dose in Self-Compacting Concrete leads to gain of

good self-compaction ability in addition to marginal reduction in unit weight. Moreover, there is

also slightly increase in compressive strength than that of normal concrete mix.

Shanthappa et al (2013), presented an experimental investigation on the effect of acid attack on

the properties of SCC produced by the combination of admixtures such as (Super-plasticizer +

Viscosity modifying admixture +Air entraining agent + Accelerator), (Super-plasticizer +

Viscosity modifying admixture +Air entraining agent +Retarder), (Super-plasticizer + Viscosity

modifying admixture +Air entraining agent + Water proofing compound ) and (Super-plasticizer

+ Viscosity modifying admixture +Air entraining agent + Shrinkage reducing admixture). The

concrete testing specimens was prepared by a mix proportion 1:2.7:6.1:5.1 with cement: fly ash:

sand: coarse aggregate with a water/binder ratio of 0.38. Specimens after 28 days of curing were

immersed in magnesium chloride solution of 5% and 10% concentrations for 90 days. Before

immersion, they were weighed accurately. After 90 days of immersion, the specimens were

removed from chloride media, washed in running water, weighed accurately and tested for their

respective strengths. Before testing, the specimens were drilled to a depth of 30mm. The powder

collected in this manner was titrated against AgNO3 solution to find chloride content in the

concrete. SCC produced with above combination of admixtures show better resistance to

chloride attack as compared to SCC produced with combination of admixtures (SP+VMA) only

Gurunaathan and Thirugnanam (2014), attempted to replace part of cement by Ground

Granulated Blast Furnace Slag (GGBS), Fly Ash (FA), Rice Husk Ash (RHA) and Silica Fume

(SF) to improve the durability properties of concrete. One of the most requirements of concrete is

that it should be durable under certain conditions of exposure. Deterioration can occur in various

forms such as alkali- aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts,

shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground

water, sea water attack, and corrosion caused by salts. Addition of admixtures may control these

effects. In this paper, suitable admixtures to improve the durability characteristics and the

optimum percentage of replacement of cement by mineral admixtures with various proportions

have been studied.

Concrete is an artificial material, which is made up of cement, fine aggregate, coarse aggregate

and water. In this paper, an attempt has been made to replace part of cement by Ground

Granulated Blast Furnace Slag (GGBS), Fly Ash (FA), Rice Husk Ash (RHA) and Silica Fume

(SF) to improve the durability properties of concrete. One of the most requirements of concrete is

that it should be durable under certain conditions of exposure. Deterioration can occur in various

forms such as alkali- aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts,

shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground

water, sea water attack, and corrosion caused by salts. Addition of admixtures may control these

effects. In this paper, suitable admixtures to improve the durability characteristics and the

optimum percentage of replacement of cement by mineral admixtures with various proportions

have been studied.

Wei (2010), showed the effect of chemical admixture on the strength development of palm oil

fuel ash (POFA). It was seen that POFA is considered a pozzolanic material and it can act as a

cement replacement for producing concrete with higher strength, low cost and good durability of

concrete. For blended cement, water binder ratio is always reduced due to the cement in concrete

being replaced by pozzolanic material. Therefore, the super plasticizer which is one type of

chemical admixtures will be added to blended cement concrete in order to improve the

workability of concrete. But for strength development of POFA concrete, there will be some

effects when chemical admixtures are added. In this research, the control mix is POFA as partial

cement replacement material. While other POFA concretes contain super-plasticizer with

different percentage at 0.5%, 1% and 1.5%. To investigate the fresh concrete properties, the

slump test was conducted. While for hardened concrete properties, compressive strength test,

flexural strength test and splitting tensile test were conducted. Strength development of POFA

concrete was studied during all tests for hardened concrete properties. Conclusively, super-

plasticizer added into POPA concrete will improve both workability and strength of POFA

concrete.

Chandana and Banu (2015) reported that cement concrete occupies the most important role in the

field of civil engineering. It mainly consists of cement, fine aggregate and coarse aggregate. In

the concrete, the cement acts as a binding material for fine aggregate and coarse aggregate. Many

investigations have been done on fly ash and artificial sand individually. The utility of fly ash as

partial replacement in concrete mixes is rise on these days. An attempt have been made to

examine the suitability of replacing the 30% of fly ash and 50% of artificial sand for a concrete

of grade m35. Examine strength characteristics such as compressive strength of concrete mix for

7 days, 28 days, 56 days of curing period and durability characteristics such as acid attack test,

acid durability factor, and acid attack factor of concrete mix for 30 days, 60 days, 90 days results

are analyzed and compared with the conventional mix.

Pravallika and Lakshmi (2014), showed that potable water is the most important ingredient in the

making of conventional concrete and concrete is the most widely used material in the world next

to water. Only 2.5% of the world’s water bodies are said to be of fresh water and the remaining

constitute of sea water. According to the report of the World Meteorological Organization, more

than half of the world’s population would not have enough drinking water by 2025. The

construction officials in coastal areas have long been facing the challenge of building and

maintaining durable concrete structures in a salt water environment. Gradual penetration of sea

salts and the subsequent formation of expansive and leachable compounds lead to disintegration

of structural concrete. Cement is the most costly and energy intensive component of concrete.

The unit cost of concrete can be reduced as much as possible by partially replacing cement with

fly ash. Fly ash is available in abundance as a by-product from thermal projects in India. Waste

products like fly ash, (which otherwise is hazardous to the atmosphere, may be used as part

partial replacement of cement with fly ash and the fly ash) when used in concretes have been

known to have higher resistance to chloride ion penetration than concrete made with ordinary

Portland cement. In the present study two grades of reference fly ash concrete M20, M25 were

prepared using potable water for mixing and curing. The same grades of fly ash concrete were

once again prepared using potable water for mixing and cured in sea water. Once again the same

grades of fly ash concrete were prepared using sea water for mixing as well as curing.

Investigation was carried out for fresh concrete properties and hardened concrete properties on

specimens cured for 7, 28 & 90 days.

Ashar et al (2013), investigated on 4 super plasticizers, on the basis of the workability test on

cement paste two SP’s were selected for further studies and to compare their effects on mortar

properties such as workability, compressive strength, water reduction and tensile strength. Two

different mortar mixes (1:1.5 and 1:2) were tested for three values of w/c ratio (0.3, 0.35, and

0.4) for varying SP dosage i.e. from 0.6 to 2%. This paper presents an experimental investigation

on strength aspects such as compressive, and split tensile strength of self-compacting concrete

containing fly ash and workability tests (slump flow, T500mm, V-Funnel and T5min) are carried out.

The methodology adopted is that Portland cement is replaced by 0%, 35% and 50% of fly ash

using two types of super plasticizers (SNF, PCE) and performance is measured and compared.

Abas and Mahyuddin (2014) showed that Super-plasticizers are used for the improving

workability and reducing the water to cement ratio. The presence of super-plasticizers in a

concrete mixture is quite advantageous, in that they assist in the effective dispersion of cement

particles and hence improving the workability of concrete. The purpose of this research study is

to examine and study the influence of engineering performance of super-plasticized concrete

with a different percentage added. The types of superplasticizer that are going to be tested are the

Conplast SP1000 which consists of sulphonated naphthalene polymers. Conplast SP1000

disperses the fine particles in the concrete mix, enabling the water content of the concrete to

perform more effectively. Three different percentage of superplasticizer used are 1.75%, 2.25%

and 3%. Every each percentage will reduce the quantity of water in the design mixture. Every

specimen was tested on the duration of 7, 28 and 56 day with 3 specimen cube and prism for

every level.