The knowledge about "civil engineering" provided by Er. Md Faiz Ali through this plateform is absolutely correct and verified based on practical knowledge and good experiences.

A major project on

Strength studies on ternary blended concrete using "fly ash and silica fume"


ABSTRACT
Concrete is widely used in various types of construction from flooring of huts to a multi-stored high rise structures. It is one of the versatile, heterogeneous material of Cement, Fine aggregate Coarse aggregate, Water, Environmental concern, steaming from high energy expenses, Carbon dioxide emission have brought pressure to reduce consumption of cement through use of supplementary  cementious material  i,e  fly ash ,GGBS ,micro silica and metakaolin are the some of the pozzolonas used as cement replacement material, Cement with replacement of Fly ash and GGBS has emerged as a  major alternative to conventional concrete Industry. These is due to because of  cement saving, energy saving, cost saving and  Environmental  Benefits.
           
                        The conventional concrete has lost its usage in modern days as it does not serve the present needs. Hence to improve the workability, durability and the ultimate strength of the concrete, conventional concrete with super plasticizers and pozzolans are used.  Durability of concrete is defined as its ability to resist weathering action, chemical attack, abrasion or any other process of detoriation. It also includes the effects of quality and serviceability of concrete when exposed to sulphate and chloride attacks. It is the material of choice where strength, durability, impermeability, fire resistance and abrasion resistance are required. The main aim of the present study is to determine the compressive strength, split tensile strength of concrete mix of M30 grade, with partial replacement of cement with SILICA FUME and FLY-ASH.

                            In this paper our study is mainly confined to evaluation of changes in compressive strength, split tensile strength in six different mixes of M30 Grade namely conventional aggregate concrete (CAC), concrete is made by replacing 15% of cement by Fly Ash and 5% Silica Fume(FASF1),concrete is made by replacing 15% of cement by Silica Fume and 5% of Fly Ash(FASF2), concrete is made by replacing 10% of cement by Fly Ash and 10%Silica Fume (FASF3),concrete is made by replacing of cement by 12% Fly Ash and 8% of Silica Fume (FASF4), concrete is made by replacing of cement by 8% Fly Ash and 12% of Silica Fume(FASF5)  respectively .


TABLE OF CONTENTS
1.                  INTRODUCTION                                                                                             
1.1              Introduction                                                                                              01
1.2              Blended Cements                                                                                     03
1.2.1 Advantages of blended concrete                                                      06
1.3              Triple-Blends (Ternary Cement System)                                                 06
1.4              Effect Of Ternary Cement System                                                           07
1.5              Fly Ash                                                                                                     07
1.6              Silica Fume                                                                                              08
1.7              General overview of Pozzolona’s concrete                                              09
1.8              Super plasticizer                                                                                       11 
2.                  LITERATURE REVIEW                                                                          
             2.1      General                                                                                                                  12
             2.2       Earlier researches                                                                                                 13
             2.3       Critical observations from the literature                                                              15
3.                  SCOPE AND OBJECTIVE OF PRESENT WORK                              
3.1            Scope and objective                                                                                16
4.                  MATERIALS AND PROPERTIES                                                                                                                   4.1       Introduction                                                                                              17
 4.2       Cement                                                                                                     17
4.2.1     Reaction Mechanism of cement                                                  19
4.2.2     Ordinary Portland cement                                                           20
 4.3        Blended cement                                                                                       20
 4.4        Aggregates                                                                                               21
4.4.1     Fine Aggregates                                                                          21
4.4.2     Coarse Aggregates                                                                      23
 4.5        Admixtures                                                                                              23
  4.6        Role of Fly Ash in cement                                                                     24
4.6.1     Reaction mechanism of Fly Ash                                                27 
4.6.2      Advantages of Fly Ash                                                              28
4.7        Silica Fume                                                                                              28
4.7.1    Chemical properties                                                                     29
4.7.2     Reaction Mechanism of Silica Fume                                          30
4.7.3     Advantages of Silica Fume                                                         30
5.                  EXPERIMENTAL PROGRAMME                                                                     
5.1    Outline present work                                                                                     31
5.2    Experimental programme                                                                              31
5.3     Sequence of operation                                                                                  32
                        5.4.    Work Plan                                                                                                     32
                        5.5    Physical and Chemical properties of material                                               33
5.5.1 Cement                                                                                             33
5.5.2 Fly Ash                                                                                             33
5.5.3 Silica Fume                                                                                      33
5.5.4 Fine Aggregate                                                                                 33
5.5.5 Coarse Aggregate                                                                             35
5.5.6 Water                                                                                                36
5.5.7 Blended Cement                                                                               36
                      5.6      Mixing performance And Casting Performance of concrete                         36
5.6.1 Mixing                                                                                              36
5.6.2 Casting of specimens                                                                        37
5.6.3 Placing and curing                                                                            38
                       5.7    Testing Programme                                                                                         39 
5.7.1 Slump cone test                                                                                39
5.7.2 Compressive Strength of concrete                                                   39
5.7.3 Split Tensile Strength of Concrete                                                   39
                       5.8 Tests for Compressive Strength of Concrete                                                     40
                       5.9 Tests for Split Tensile Strength of Concrete                                                      41
6.         DISSCUSSION OF TEST RESULTS              
             6.1   Compressive Strength Results                                                                       44
            6.2   Split Tensile Strength Results                                                                         45     
7.         CONCLUSION                                                                                                    
             7.1 Conclusion                                                                                                       48
             7.2 Scope and further study                                                                                   50
APPENDIX                                                                                                                        51
REFFERENCES                                                                                                               53


LIST OF FIGURES

 FIG NO.                    FIG. TITLE                                                                PAGE NO.
Fig 1                          Fly Ash Powder                                                                    08
  Fig 2                          Silica Fume                                                                           09
  Fig 3                         Ultra-Tech 53 Grade Cement                                                18
  Fig 4                         Mixing Materials For Casting Specimens                             37
  Fig 5                         Casting of Concrete Cubes                                                    37
  Fig 6                         Normal Water Curing                                                            38
Fig 7                         Slump Cone Test                                                                    39            
Fig 8                         Test For Compressive Strength of Concrete                          40
Fig 9                         Test For Split Tensile Strength of Concrete                           42

LIST OF TABLES

TABLE NO                            TABLE TITLE                                               PAGE NO.

Table 1:4.2                  Physical properties of Ordinary Portland Cement                  20
Table 2:4.4.1               Properties of Fineness Aggregate                                           22
Table 3:4.4.2               Properties of Coarese Aggregate                                             23
Table 4:3.6                 Availability and utilization of fly ash in various countries      27
Table 5:5.6                  Work Plan                                                                                32     
Table 6:5.5.4               Analysis of Fine Aggregate                                                     34
Table 7:5.5.5               Sieve Analysis of coarse Aggregate                                        35
Table 8:6.1.1               Compressive Strength Results For Normal Water Curing      44
Table 9:6.2.1               Split Tensile Strength Result For Normal Curing of Water    46

LIST OF GRAPHS
GRAPH NO.                                      GRAPH TITLE                                              PAGE NO.

Graph1                        Compressive Strength For Normal Water Curing                               45
Graph2                        Split Tensile Strength Result For Normal Curing of water                47
CHAPTER 1 
INTRODUCTION

1.1. INTRODUCTION:
             Concrete is the most widely used man-made construction material in the world. It is obtained by mixing of fine aggregates, coarse aggregates and cement with water and sometimes admixtures in required proportions. Fresh concrete or plastic concrete is freshly mixed material which can be molded into any shape hardens into a rock-like mass known as concrete. The hardening is because of chemical reaction between water and cement, which continues for long period leading to stronger with age. The utility and elegance as well as the durability of concrete structures, built during the first half of the last century with ordinary Portland cement (OPC) and plain round bars of mild steel, the easy availability of the constituent materials (whatever may be their qualities) of concrete and the knowledge that virtually any combination of the constituents leads to a mass of concrete have bred contempt. Strength was emphasized without a thought on the durability of structures. As a consequence of the liberties taken, the durability of concrete and concrete structures is on a southward journey; a journey that seems to have gained momentum on its path to self– destruction. This is particularly true of concrete structures which were constructed since 1970 or thereabout by which time the following developments are came subsequently.
            The setback in the health of newly constructed concrete structures prompted the most direct and unquestionable evidence of the last two/three decades on the service life performance of our constructions and the resulting challenge that confronts us is the alarming and unacceptable rate at which our infrastructure systems all over the world are suffering from deterioration when exposed to real environments.
            The Ordinary Portland Cement (OPC) is one of the main ingredients used for the production of concrete and has no alternative in the civil construction industry. Unfortunately, in the production of cement involves emission of large amounts of carbon-dioxide gas into the atmosphere, a major contribution for green house effect and the global warming. Hence it is inevitable either to search for another material or partly replace it by some other materials to save our environment. The search for any such cementitious material, which can be used as an alternative or as a supplementary for cement should lead to global sustainable development and lowest possible environmental impact.
             By doing  experimental studies we found some materials like  Fly ash, Ground Granulated Blast furnace Slag (GGBS), Rice husk ash, High Reactive Met kaolin, and Silica fume are some of the pozzolanic materials which having the similar properties of cement can be used in concrete as partial replacement of cement. A number of studies are going on in India as well as abroad to study the impact of use of these pozzolanic materials as cement replacements and the results are encouraging. The strength, durability, workability and other characteristic of concrete depends on the properties of its ingredients, proportion of mix, method of compaction and other controls during placing and curing.
             With the passage of time to meet the demand, there was a continual quest in human being for the development of high strength and durable concrete. The history of high strength concrete is about 35 years old, in late 1960s the invention of water reducing admixtures lead to the high strength precast products and structural elements in beam were cast in situ using high strength concrete. Since then the technology has come of age and concrete of the order of M60 to M120 are commonly used. The definition of high strength concretes is continually developing. In the 1950s 34MPa was considered high strength, and in the 1960s compressive strengths of up to 52MPa were being used commercially. More recently, compressive strengths approaching 120MPa have been used in cast-in-place buildings. The advantage of pre stressed concrete technology has given more impact for making concrete of high strength. In India high strength concrete is used in pre stressed concrete bridges of strength from 35MPa to 45MPa. Present     (in 2000) Concrete strength of 75MPa is being used for the first time in one of the flyover at Mumbai. Also in construction of containment Dome at Kaiga power project used HPC of 60MPa with silica fume as one of the constituent. In Hyderabad metro rail project they are using 60MPa for the construction of flyover bridge columns.
  The reasons for these demands are many, but as engineers, we need to think about the durability aspects of the structures using these materials. With long term durability aspects kept aside we have been able to fulfill the needs. The concrete of these properties will have a peculiar Rheological behavior.
         Now a day the construction industry turning towards pre-cast elements and requirement of post-tensioning has made the requirement of the high strength of concrete invariable and the engineers had to overcome these drawbacks, which to a great extent we have been able to do. But today the construction industry is to achieve the savings in concrete and also economy in financial aspects.
1.2 BLENDED CEMENTS:
              Cement mixtures containing ordinary Portland cement (OPC) and at least one Supplementary cementitious materials (SCM) are called blended cements. Class C fly ash is often used as a SCM to improve concrete workability and reduce cost, as well as for other technical reasons. Blended cements blended or inter ground at cement plants are generally more uniform and produce better results than blended concrete mixtures combined at the concrete mixer.
              Cement mixtures containing Ordinary Portland Cement along with one supplementary cementitious material is called Binary Blended Cement. And A Cement mixtures containing Ordinary Portland Cement along with two supplementary cementitious materials is called Tripple Blended Cement.
             Evidence of the first blended cements dates back to Roman times, when volcanic ash was used in a crude blend with slaked lime to give the user a product that developed higher early strength than the usual slaked lime as well as significant durability. Evidence of this can be seen in the Aqueducts and the Colosseum in Rome.
             The area in Italy where the volcanic ash was discovered is called Pozzolana, hence the term for a reactive substance being called a pozzolana. Some academics have assumed that the Roman Empire discovered the process of cement manufacturing, which was lost with the decline of this emperor and rediscovered in the nineteenth century in Britain. In truth, it is more likely that the lime the Romans calcined (burnt) for the purpose of slaking approached an argillaceous lime in chemical composition and hence had to be milled rather than naturally slaked. When mixed in the normal manner with water, this product showed large early strengths and was probably the first cement made.
            It is a fact that their use save energy and conserve natural resources but their technical benefits are the strongest. They affect the progress of hydration, reduce the water demand and improve workability. The concrete containing Ground Granulated Blast Furnace slag (GGBS), on vibration becomes ‘mobile’ and compacts well. Silica fume greatly reduces, or even eliminates bleeding; the particles of Pozzolanic Fly Ash (PFA) are spherical and thus improve the workability. Their inclusion has the physical effect of modifying the flocculation of cement, with a resulting reduction in the water demand. The pore size in concrete is smaller. The fine particles ‘fit in between cement particles, thereby reducing permeability. 
           The 28 days and later, compressive strengths are same as for Ordinary Portland Cement.  However, the rate of gain of strength up to 7 days is slower, due to heat of hydration being low. The drop in early strength should not be considered as sign of poor quality as this is often accompanied by enhancement of other properties.
           Curing is a very important stage in the life of a conventional concrete, it becomes a critical factor in concrete containing blended cement. A good curing method is essential, because blended cement hydrates slower than OPC. It is potentially more vulnerable to drying conditions, thus the wet curing requirements, which is the most neglected activity in the fields, is very important. The curing method and period must be specified.
              The Fly ash (FA), Ground Granulated Blast Furnace slag (GGBS), Silica fumes being finer than OPC, less bleeding is observed. The freshly placed concrete is very stable, being very cohesive and having strong internal cohesion. This has a negative effect in the form of plastic shrinkage.
              The workability increases, and thus water content can be reduced by about 3%. The ‘ball bearing’ action of cementations particles improves the workability. Silica fumes demand high water due to higher fineness. The problem is circumvented by the addition of suitable super plasticizers.
             Recent research evaluated the behavior of concrete made with supplementary cementitious materials (SCMs) such as fly ash and silica fume under a various conditions. Correlations were found among the source and proportion of the Supplementary cementitious materials (SCM), curing conditions, concrete set time, maturity, strength development, and cracking potential.
           The blended cements are manufactured by adding pozzolanic or Cementitious materials like fly ash or ground granulated blast furnace slag (GGBS) or condensed silica fumes (CSF) to Portland cement clinker and Gypsum. Alternatively, these pozzolanic and cementitious materials can be introduced into Portland cement concrete during concrete making operations.
          The following shown Table gives the details of mineral admixtures, being used to make blended cement. Classification, composition and particle characteristics of mineral admixtures for concrete.
          The addition of fly ash, silica fume and other industrial byproducts to cements can improve concrete workability, durability, and long-term strength, but a gap in knowledge about the variation in performance of concrete containing Supplementary cementitious materials (SCM) from various sources has limited its use by the Portland Pozzolona cement (PPC) for  paving industry.
           In this project we have used triple blending concrete, which contains different percentage of fly ash (FA) with different percentage of silica fume along with ordinary Portland cement (OPC). In which fly ash (FA) starts from 5%, 8%, 10%, 12%,15% replacement and silica fume (SF) from 5%, 8%, 10%, 12%,15% replacement in cement content. Concrete performance varies with the source and proportion of cementitious materials used.
              Fly ash (FA) can function as a water-reducing agent in cement mixtures. As a result, ternary cement concrete can achieve the same flow ability as ordinary Portland cement concrete.
               Fly ash replacement in binary cements generally increases paste/concrete setting time when compared with Ordinary Portland cement concrete.Slag replacement in ternary cements can either increase or decrease the set time, depending on the type of clinker used when compared with binary cement concrete.
1.2.1 ADVANTAGES OF BLENDED CONCRETE:
The Engineering benefits likely to be derived from the use of mineral admixtures (blended cements and cement mineral admixtures can be used interchanging) in concrete are improved resistance to thermal cracking because of lower heat of hydration, enhancement of ultimate strength, reduction in permeability due to pore refinement, and a better durability to chemical attacks such as chloride, sulphate water, soil and alkali-aggregate expansion.
        The beneficial effect of various cementitious materials are so significant that their use in reinforced concrete liable to corrosion in hot climates (which is the condition prevailing in entire India during most part of the year), is virtually necessary. Portland cement alone should not be used in future marine structures and in coastal areas i.e. within 1 Km of coast line.
       At present in India ordinary Portland cement is considered as the ‘best’, if not the sole, cementitious material in the concrete. The other materials, primarily fly ash and silica fume are viewed as replacements or substitutes for cement, whereas these cementitious materials are today concrete ingredients in their own right.
·         Improved concrete workability
·         Lower risk of thermal cracking
·         Improved concrete durability and long-term strength
·         Reduced overall concrete cost.
1.3. TRIPLE-BLENDS (TERNARY CEMENT SYSTEM)
It means micro silica or other cement replacement additives are to be used with OPC only. That is not strictly true and ternary mixtures comprise efficient -systems. The primary incentive of adding limited amount micro silica –for example 5 percent with ground granulated blast furnace slag cement mixes was to ensure high early strength research has however, shown that ternary mixtures of OPC, micro silica and ground granulated blast furnace slag result in synergic action to improve the micro structure and performance of concrete. When both micro silica and fly-ash are used, the resultant enhancement of strength or pozzoloanic activity was greater than super position of contributions of each, for the respective proportions. Such synergic effect results from strengthening the weak transition zone in aggregate cement interface, as well as segmentation and blocking of pores.
Depending upon the service environment in which it is to operate, the concrete structure may have to encounter different load and exposure regimes. In order to satisfy the performance requirements, different ternary compounds required. Such as cement, fly-ash, Microsilica. Greater varieties are introduced by the corporation of additives like pozzoloana, granulated slag are inert fillers this leads to different specifications of cements in national or international.
1.4.  EFFECTS OF TERNARY CEMENT SYSTEM

The combination of micro silica and fly ash in a ternary cement system (i.e., Portland cement being the third component) should result in a number of synergistic effects, some of which are obvious or intuitive, as follows:
  • Micro silica compensates for low early strength of concrete with low CaO fly ash.
  • Fly ash increases long-term strength development of micro silica concrete.
  • Fly ash offsets increased water demand of micro silica.
  • Micro silica reduces the normally high levels of high CaO fly ash required for sulphate    resistance and ASR prevention.
  • Very high resistance to chloride ion penetration can be obtained with ternary blends.
  • Fly ash due to presence of spherical particles that easily rollovers one another reducing inter partial friction (call bearing effects) leads to improved workability and reduction in water demand.
1.5        FLY ASH
Fly ash is an unavoidable solid waste   product of coal-fired thermal power plants. Coal being the  primary and  principal  source  of   electricity,  the  problem of  fly  ash  disposal   and/orutilization has assumed enormous proportions as the production of fly ash is of the order of 1 to 1.5 billion tons  annually in the world.  If ways are not   found for recycling of fly ash, Itcould lead to serious disposal problems. Fly ash is mainly two types Fly ash Class C(high-calcium FA).  and Fly ash Class F(low –calcium FA)
Class C Fly Ash:
Fly ash produced from the burning of younger lignite or sub-bituminous coal, in addition to having pozzolanic properties, also has some self-cementing properties. In the presence of water, Class C fly ash hardens and gets stronger over time. Class C fly ash generally contains more than 20% lime (CaO).
Class F Fly Ash:
The burning of harder, older anthracite and bituminous coal typically produces Class F fly ash. This fly ash is pozzolanic in nature, and contains less than 20% lime (CaO). 
Fig:1   Fly Ash Powder
1.6.  SILICA FUME
Silica fume is “ very fine non-crystalline silica producedinelectric arc  furnaces   as  a  byproduct ofthe production of elemental silicon or alloys containing  silicon”. It is usually agray colored powder, somewhat similar toPortland cementor somefly ashes. Microsilica is a by-productof producingsilicon metal or ferrosiliconalloysin smelters usingelectric arc furnaces.
Fig: 2   Silica fumes
1.7.   GENERAL OVERVIEW ON POZZOLONA’S  IN CONCRETE
The use of pozzolanic materials is as old as that of the art of concreteconstruction. It wasrecognized long time ago, that thesuitable Pozzolona used in appropriate amount, modifycertain properties of fresh and hardened mortars and concretes.
In recent years, pozzolanicmaterialsarebeing usedas an addition or partial replacementfor the moreexpensive Portland cement to improve the properties of the concrete.Pozzolanicmaterials are siliceous and aluminous materials which possess little or nocementitious value,but, in finely divided form and in the presence of moisture, chemically react with calciumhydroxide (lime) liberated on hydration at ordinarytemperatures to form compounds(calcium, silicate, hydrate gel) possessing cementitiousproperties. The calcium hydroxide,otherwise a water soluble material, is converted intoinsoluble cementitious materials by theuse of pozzolanic materials. The action is termedas ‘Pozzolanic action'.
The reaction can be shown as
Pozzolona + Calcium Hydroxide + Water C – S – H (Gel)
This reaction is called pozzolanicreaction. The characteristic feature of pozzolanic reactionis  firstly slow,with the result that heat of hydration and strength developmentwill be accordingly slow. The reaction involves the consumption of Ca (OH)2 and notproduction of Ca (OH)2. The reduction of Ca (OH)2 improves the durability of cementpaste by making the paste dense andimpervious.It has been amply demonstrated that the best Pozzolonain optimum proportions mixedwith Portland cement improves many qualities of concrete, such as:
                                                i.            Lower the heat of hydration and thermal shrinkage
                                              ii.            Reduce the alkali-aggregate
                                            iii.            Improve resistance to attack by sulphate soils and sea water
                                            iv.            Improve extensibility
                                              v.            Lower costs
                                            vi.            Improve workability
                                          vii.            Lower susceptibility to dissolution and leaching
                                        viii.            Increase the water tightness
In addition to these advantages, contrary to the general opinion, good Pozzolona willnot unduly increase water requirement or drying shrinkage.
Pozzolanic materials can be divided into two groups, namely
        1. Natural Pozzolona’s                               2.Artificial Pozzolona’s
The natural Pozzolona’s are
a) Clay and shale’s
b) Opaline shale’s
c) Diatomaceous earth
d) Volcanic tuffs and
e) Pumicities
On the other hand the artificial Pozzolona’s are
a) Low calcium fly ash
b) High calcium fly ash
c) Micro Silica
d) Surkhi
e) Met kaolin
f) Rice Husk ash
1.8.  SUPER PLASTICIZER
Super plasticizers, also known   as high range water reducers, are chemicals used   asadmixtures where well-dispersed particle suspensions are required. These polymers are usedas dispersants to avoid particle aggregation, and to improve the flow characteristics.
Their addition to concrete or mortar allows the reduction of the water to cement ratio, notaffecting the workability of the mixture, and enables the production of self-consolidatingconcrete and high performance concrete. Thiseffect drastically improves theperformanceof the hardening fresh paste. Indeed the strength of concrete increase whenever the amountof water used for the mix decreases.
These are morerecent and more effective type of water reducing admixtures also knownas high range water reducer. The main benefits of super plasticizers can be summarized as follows:
   Increased fluidity:
·         Flowing
·         Self-leveling
·         Self-compacting concrete
·         Penetration and compaction round dense reinforcement
Reduced w/c ratio:
·         Very high early strength, >200 % at 24 hours or earlier
·         Very high later age strength,>100 MPa
·         Reduced shrinkage, especially if combined with reduced cement content.
Improved durability by removing water to reduce permeability and diffusion
CHAPTER - 2
LITERATURE REVIEW
2.1  GENERAL
Extensive research work both at National and International level has been done on the use of various admixtures in concrete with common goals are:
®    To bring down the increasing cost economics of cement & building blocks.
®    To modify the properties of traditional concrete to the desired level suitable to the specific circumstances.
®    To conserve the natural resources used in the production of construction materials.
®    Of late, rehabilitee the existing structures which are deteriorated over period of time etc.
          In India, only government educational and research institutions and consultants are responsible for research. While in advanced countries the most remarkable break troughs have been achieved by the building material industries and their R&D laboratories.
         An accepted fact is that these encouraging results on the use of admixtures are not penetrating into the user community and the entire research work is getting flocked in their organizations. With the result, the very purpose of research work is becoming questionable. Along with and R&D units, the policy makers and consultants should take more interest in handling these issues directly keeping not only the techno-economics in view but also national obligations.
        As our aim is to develop concrete which does not only concern on the strength  of concrete, it also having many other aspects to be satisfied like workability, performance, durability and also economy. So for this we need to go for the addition of pozzolanic materials along with super plasticizer with having low water cement ratio. The use of silica fume is many, which is having good pozzolanic activity and is a good material for the production high performance concrete.
2.2.  EARLIER  RESEARCHES:
           Some of the early research works had done using different pozzolanic materials with the replacement of cement using super plasticizer for the development high Strength concrete and high performance concrete. Also the development in the field of fiber reinforced concrete along with Pozzolona’s. And also developments on binary blended cements. Some of the over views of different studies has been represented here below.
A.K.Mullick (2007)1:
Described among the many factors that govern the durability and performance of concrete in service, type of cement receives greater attention. In his paper he describes the characteristics of cementitious systems required to meet the diverse requirements of strength and durability of concrete and highlights the advantages of part replacement of OPC by fly ash, granulated slag and silica fume- either singly or in combination in ternary blends.
Deepa A Sinha(2012)2

The main objective of this research was to investigate the properties of ternary blended concrete incorporating silica fume, metakaolin, and GGBS. The properties investigated include workability, compressive strength and. flexural strength. In this project, we have replaced cement by ternary blend of Fly ash, metkaolin, silica fume, GGBS up to 30% to determine the workability, compressive strength and flexural strength. By using supplementary cementitious materials we found that replacement of cement with Fly-ash gives higher strength than normal concrete at 28days and 90days.Replacement of cement with 15% fly-ash and 15% metakaolin gives the best results as compare to other mixes for compressive strength of 28 days. Under two point loading arrangement used for flexural strength testing, the failure occurs in middle third portion of the specimen. In case of TBC, the failure is sudden and through the aggregates.

Md. Rezaul Karim, Md. Maruf Hossain, Mohammad Nabi Newaz Khan (2014)3

 The experimental results reveal that AAB-mortar exhibits less flow than that of ordinary Portland cement (OPC). Surprisingly, AAB-mortars (with 2.5 molar solution) achieved a compressive strength of 34.3 Mpa at 28 days, while OPC shows that of 43.9 Mpa under the same conditions. Although water absorption and porosity of the AAB-mortar are slightly high, it shows excellent thermal resistance compared to OPC. Therefore, based on the test results, it can be concluded that in the presence of a chemical activator, the aforementioned pozzolans can be used as an alternative material for cement.
M.G. Alexander, B.J. Magee (1999)4
They describes a short-term study carried out to examine the durability performance of various condensed silica fume (CSF) concretes in comparison to Portland cement (PC) and PC/ground granulated blast furnace slag (GGBS) controls up to the age of 28 days. Mix proportions were designed to provide 28-day strengths of 30, 40, and 50 MPa for the PC controls and these were used for all binder combinations considered. Concrete durability was inferred from a suite of durability index tests designed to measure concrete resistance to gas, liquid, and ion transport mechanisms. It is shown that concrete durability is dramatically improved through the use of CSF. Optimum performance was achieved through the use of CSF as a 10% addition by mass to the initial binder content. The work also confirms CSF’s effectiveness when used in ternary binder blends with PC and GGBS, with these mixes out-performing the controls and selected binary blended PC/CSF mixes.
P. Murthi and V. Sivakumar (2008)5
They describes a detailed experimental investigation on the acid resistance of ternary blended concrete immersed up to 32 weeks in sulfuric acid (H2SO4) and hydrochloric acid (HCl) solutions. The results are compared with those of the control and binary blended concrete. ASTM class F GGBS was considered to develop the binary blended concrete at the replacement level of cement as 20% by weight. Then silica fume was considered to develop the ternary blended concrete and the replacement of cement in the ternary system by silica fume was suggested as 8% of total powder content by weight. The variable factors considered in this study were concrete grades (M20, M30 and M40) and curing periods (28 days and 90 days) of the concrete specimens. The parameter investigated was the time in days taken to cause 10% mass loss and strength deterioration factor of fully immersed concrete specimen in a 10% HCl and 5% H2SO4 solutions. The investigation indicated that the ternary blended concrete prepared by 20% GGBS and 8% silica fume performed better acid resistance than the ordinary plain concrete and binary blended concrete.
2.3  CRITICAL OBSERVATIONS FROM THE LITERATURE:
           Only one pozzolanic materials combination is used with Ordinary Portland cement i.e., binary blended cements only.
·         Micro Silica incorporation in concrete results in significant improvements in the      workability of concrete, along with the compressive strength.
·         The maximum percentage of synthetic fiber to be used in concrete along with silica fume to get good outcome.
·         A typical 1000 mega watt station using coal of calorific value 3500 kilo cal.  per kg.and ash   content of 4 to 4.5 per cent would need about 500 acres for disposal of  fly ash during its useful operation of 30 years
CHAPTER – 3
           SCOPE AND OBJECTIVE OF PRESENT WORK
3.1  SCOPE AND OBJECTIVE:
  • The objective of the present study is to investigate the workability, strength  behaviours for M30 grade concrete by replacing 20% of cement with fly ash and silica fume.
  • We also investigate different basic properties of concrete such as compressive strength and split tensile strength and and comparing the results of different proportional.
  1. In First stage  finding  strength of concrete by replacing cement with Silica Fume and Fly Ash in minor quantity and curing in water.
  2. In  Second stage ,finding  strength of concreteby replacing cement with Silica Fume and Fly Ash in minor quantity and curing in water along with 5% of acid.
  3. From the above two ,we can study about concrete in which cement is replaced by Silica Fume and Fly Ash  in acidic environmentby the comparison of normal curing and acid curing.

CHAPTER – 4
MATERIALS AND PROPERTIES
4.1.  INTRODUCTION:
               The Quality of concrete can be achieved by the selection of suitable materials, cementitious materials, admixtures, the choice of mix proportion, water cement ratio and use of proper methods of mixing, placing and curing. All these aspects depends upon the selection of materials and admixtures.
            Usually the materials used in concrete are cement, aggregates, water and admixtures. And in this present work we are using Ordinary Portland cement (OPC) of Ultratech company and the cementitious   materials silica fume form ferrosilicon alloyproduction(M/s ELKEM Pvt Ltd, Bombay) and  fly ash (FA) carried from thermal power station, Vijayawada. And locally available fine and coarse aggregates confirming to IS 383-1970 is used.
4.2.  CEMENT:
Cement is a material that has cohesive and adhesive in the properties in the presence of water. Natural cement is obtained burning and crushing the stones containing clay, carbonate of lime and some amount of carbonate of magnesium. Natural cement resembles very closely hydraulic lime. It sets very quickly after addition of water. It is not strong as artificial cement. The artificial cement was invented by a MANSION JOSEPH ASPDIN of England. The Portland cement is a general term used to describe hydraulic cement. The typical raw material used for making cement are limestone (CaCO3), sand (SiO2), Slate ,clay (SiO2, Al2O3 or Fe2O3), and iron oxide (Fe2O3). Thus the chemical components of cement are calcium (Ca), silicon (Si), aluminum (Al) and iron (Fe). The calcareous component, lime, CaO is derived from limestone, chalk, marble, lime sand shell deposit, lime sludge. The argillaceous component (SiO2, Al2O3 or Fe2O3) is derived from clay, shale, tuff, ash, slate, glass.
           Ordinary Portland cement is the basic Portland cement and is the best suited for use in general concrete construction. Where there is no exposure to sulphates in the soil in the ground water. This cement consists primarily of silicates and aluminates of lime obtained from stone and clay. This moisture is grounded, blended fused in kiln at high temperature of 1400 degree Celsius and a product called clinker is obtained. The clinker is cooled and grounded to get cement. This cement is produced in maximum quantity than the other attacks. Grinding Portland clinker with the possible addition of small quantity of gypsum, water or both not less than 1% of air entraining elements produces it.
           Cement is a material that has cohesive and adhesive properties in the presence of water. Such cements are called hydraulic cements. These consist primarily of silicates and aluminates of lime obtained from limestone and clay. There are different types of cement; out of that I have used ordinary Portland cement (OPC) of 53 grade from Ultratech company for this present study.
Fig: 3   Ultra-Tech 53 Grade Cement
4.2.1.  REACTION  MECHANISM  OF  CEMENT:
              The reaction of cement when mixed with water is called hydration. Both C3S and C2S make up nearly 75% of cement. The hydration of these compounds in responsible for the setting and hardening of cement. In the presence of water, the silicates and aluminates from products of hydration, which result in a hard mass over a period of time. This hard mass is known as hydrated cement paste.
Hydration of C3S:
 C3S + water = C-S-H + C-H + Heat
 Where C-S-H is Calcium silicate hydrate and C-H is calcium hydrate.
Hydration of C2S:
C2S + water = C-S-H + C-H + Heat
Where C-S-H is Calcium silicate hydrate and C-H is calcium hydrate.
Hydration of C3A:
 C3S + gypsum + water = ettringite + Heat
 C3S + ettringite + water = mono sulphoaluminate.
Hydration of C4AF:
C4AF + gypsum + water = ettringite + Heat
C4AF + ettringite + water = mono sulphoaluminate.
Finally the hydration reactions came summarized as follows:
2C3S + 6H = C-S-H = 3CH ( 120cal/g)
2C2S + 4H = C-S-H = CH ( 62cal/g)
C3A + 3CSH2 + 26H = C6AS3H32 (300 cal/g)
2C3A + C6AS3H32 + 4H = 3C4ASH12
C4AF + 10H + 2CH = C6AFH12
4.2.2.  ORDINARY PORTLAND CEMENT:
Ordinary port land cement (OPC) is the basic Portland cement and is best suited for use in general concrete construction. Bureau of Indian standards (BIS) has classified Ordinary Portland cement into three grades in order to produce different grade of concrete to meet the demands of the construction industry. They are 33 grade, 43 grade and 53 grade. The 53 grade cement have one of the important benefits is the faster rate of development of strength.
The experimental results of the ordinary Portland cement (OPC) of 53 grade is used.

Fineness

340 m2/kg

Specific gravity

3.02

Initial setting time (min)

98

Final setting time(min)

219

Table 1: 4.2 Physical Properties of Ordinary Portland Cement
    4.3  BLENDED CEMENTS:
            Cement Mixture containing Ordinary Portland cement and at least one cementitious materials are called Blended cements. Blended cement is a hydraulic, cementitious product, similar to ordinary Portland cement, but has certain improved properties owing to the presence of the blending material in it.
             The use of blended cement improves the properties of both fresh and hardened concrete. This can happen as a result of  the extended  hydration of  the cement pozzolanic mixture, the reduced water demand, and the improved cohesion of the paste. Another important benefit is the improvement in durability resulting from the lower permeability and improved microstructure of concrete. This arises from the reduction in pore size and the refinement of the pore structure of the cement paste as well as from improved in the properties of the “interfacial zone” between the cement paste and the aggregate surface.
4.4.  AGGREGATES:

            Theaggregate like sand, brick and stone are inert materials. Their properties greatly influence the behavior of concrete since they occupy about 70- 80% of total volume of the concrete. It is logical to use maximum of aggregates since they are less expensive then cement and are freely available in nature. The aggregates are classified as two types and comply with the requirements of IS 383-1970.
Types of Aggregates:
(1) Fine aggregate
(2)  Course aggregate
4.4.1.  FINE AGGREGATE:
              Fine aggregates are materials passing through an IS sieve that is less than 4.75mm gauge. Simply the aggregates which are passing 4.75mm sieve are called as Fine Aggregates. The most important function of the fine aggregate is to provide workability and Uniformity in the mixture. The fine aggregate also helps the cement paste to hold the coarse aggregate particle in suspension.
                Concrete is a composite material, the workability and the development of strength depend upon the age, the properties of the constituent materials and their combined action. The role of fine aggregate on strength and workability has to be deciphered before examining the possibility of total replacement of fine aggregate.
The purpose of mix proportioning is to produce the required properties in both plaster and hardened concrete by the most economical and practical combination of materials available they has been very little  used reported of vast quantities of wastes have generated by mixing and quarrying industries only small amount of this wastes are used in road making and in manufacture of building materials such as light weight aggregate bricks and autoclave red bricks an attempt is made to study the affect of rock dust as fine aggregate on the strength and workability aspects of concrete mixes.
It is evident that the concrete strength development depends upon the strength of the cement motor and its synergetic with coarse aggregate. Pebbles as coarse aggregate, due to smooth surface texture impart lower mortar aggregate bond strength than that imparted by crushed coarse aggregates. In the present work, fine aggregate consisting of natural sand conforming to grading zone II of IS 383-1970 is used.
According to IS 383:1970 the fine aggregate is being classified in to four different zone, that is Zone-I, Zone-II, Zone-III, Zone-IV. Also in cone of coarse aggregate maximum 20 mm coarse aggregate is suitable for concrete work. But where there is no restriction 40 mm or large size may be permitted. In cone of close reinforcement 10mm size also used.
                      
Properties
Results Obtained
Specific gravity
2.60
Water absorption
0.8%
Fineness modulus
2.75
Table 2: 4.4.1 Properties of Fineness aggregate

4.4.2.  COARSE AGGREGATE:
Coarse aggregates are materials which retains on an IS sieve 4.75mm gauge. Simply the aggregates which are retaining on 4.75mm IS sieve are called as Coarse Aggregates.
          The coarse aggregate used here with having maximum size of 20mm.We used the IS 383:1970 to find out the proportion of mix of coarse aggregate, with 60% 20mm size and 40% 10mm.
           For maximum strength and durability, the aggregate should be packed and cemented as compactly as possible for this reason the gradation of particle sizes in aggregate to produce close packing is of considerable importance. It is necessary that aggregate have good strength, durability and weather resistance, their surface is free from impurities such as loam, silt and organic matter which may weaken the bond with the cement paste and that no unfavorable chemical reaction takes place between them and cement.
Properties
Results Obtained
Specific gravity
2.59
Water absorption
0.4%
Fineness modulus
4.01







Table 3:4.4.2 properties of coarse aggregate:
4.5  ADMIXTURES 
Admixtures are used to modify the properties of concrete in such a way as to make it more suitable for the work at hand or for economy. Or for the purposes such as savings energy or increasing durability. In some instances the use of an admixture is the only means of achieving the desired results.

Admixtures are usually in two types of admixtures available in the market.
1.         Mineral admixtures
·         Fly ash
·         Silica fume
·         Met kaolin
·         Rice husk ash
·         Ground granulated blast furnace slag
2.         Chemical admixtures
·         Super plasticizers
·         Water reducing admixtures
·         Retarding admixtures
·          Strength increasing admixtures
From the above admixtures only mineral admixtures are used in this work are fly ash (FA) and silica fume
            The most commonly used Pozzolona’s are pumiced and pulverized fly ash because of their reaction with lime, which is liberated during the hydration of Portland cement, these material can improve the durability when added to concrete. Since they often retard the rate of setting, hardening and thus the rate of heat evolution, they can be useful in mass concrete work. The use of admixtures in concrete as a partial replacement of Portland cement is now recognized by the various British Standards. In the hardened concrete, promotes a denser matrix structure and gives good long term strength development.
4.6.  ROLE OF FLY ASH IN CEMENT
Fly ash and its classification Fly ash is comprised of the non-combustible mineral portion of coal fuelled power plant. Fly ash particles are glassy, spherical shaped “ball bearings” typically finer than cement particles that are collected from the combustion air-stream exiting the power plant. There are two basic types of fly ash: Class F and Class C. Both types react in concrete in similar ways. Both Class F and Class C fly ashes undergo a “pozzolanic reaction” with the lime (calcium hydroxide) created by the hydration (chemical reaction) of cement and water, to create the same binder (calcium silicate hydrate) as cement. In addition, some Class C fly ashes may possess enough lime to be self-cementing, in addition to the pozzolanic reaction with lime from cement hydration the main benefit of fly ash in concrete is that it not only reduces the amount of non durable calcium silicate hydrate (C-S-H), which is the strongest and most durable portion of the paste in concrete.
          Fly ash also makes substantial contributions to workability, chemical resistance and the environment. To fully appreciate the benefits of fly ash in concrete, the basics of producing exceptional concrete must be understood. Concrete is a composite material, which essentially consists of two components of aggregate and cementitious paste.
          To produce exceptional concrete, it is extremely important to have a smooth gradation of material from coarse to the finest particles (in other words, a good mix of particle sizes, so that the largest practicable coarse aggregate fills the majority of the volume, while the progressively smaller aggregate and sand fill the voids left between the larger particles). Ideally, it is best to have as much volume as possible filled with strong, durable aggregate particles, with enough paste (comprised of as much CSH and as little lime as particles) to coat every particle. Also, voids should not be present in the paste unless they are specifically provided as microscopic entrained air bubbles to provide durability in freeze-thaw environments. In real life, though, economics and local aggregate sources dictate the quality of materials used. The excess voids often exist between the aggregate particles that must now be filled by paste and air. The challenge becomes producing an approaching amount of the best possible quality paste, so that the resulting hardening paste will fill the excess voids with durability and strength approaching that of the aggregates.
          How fly ash contributes to concrete durability and strength. Most people do not realize that durability is the ability and strength are not synonymous when talking about concrete durability is the ability to maintain integrity and strength over time. Strength is only a equal cylinder strength can vary widely in their permeability, resistance to chemical attack, resistance to cracking and general deteriorations over time all of which are important to durability. Cement normally gains the great majority of its strength within 28 days thus the reasoning behind specifications normally requiring determination of 28-days strength as a standard.
         As lime cement hydration becomes available (cement tends to vary widely in their reactivity), it reacts with fly ash. Typically, concrete made with fly ash will be slightly lower in strength than normal cement concrete up to 28 days, equal strength at 28 days, and substantially higher strength for long period. Conversely, in normal cement concrete, this lime would remain intact and over a period of time it would be susceptible to the effects of weathering and loss of strength and durability.
        As previously described, the paste is the key to durable and strong concrete, assuming average quality aggregates are used. At full hydration, concrete, made with typical cements produces approximately 1/4kg of non-durable lime per kg of cement in the mix. Most people have seen concrete or masonry walls or slabs with the white, chalky surface coating or streaks called efflorescence. Efflorescence is caused on the face of the concrete being wetted and dried repeatedly or by the movement of water vapor from the damp side of the concrete to the dry side through the capillaries (voids), drawing out the water soluble lime from the concrete, block or mortar. The result is concrete that is less permeable, as witnessed by the reduction in efflorescence. Other evidence of the contribution of fly ash to strength and durability includes.
        The tallest concrete structures in the world are made with concrete where fly ash is a necessary component. Its ability to contribute to additional Calcium silicate hydrate (CSH), lower water demand, Low heat of hydration and its fine particle size are crucial to  make high strength concrete.
Country
Annual production of fly ash(MT)
Utility
Main Utilizations
U.S.A      
120
90
Structural concrete fill and cement
U.K
30

60
Light weight concrete structural fill manufacturing
Poland
60

60

China
75
50
Concrete blocks, fill materials
West germany
45

85
Mining areas
India
500

10
For constructions


Table 4:3.6 Availability and utilization of fly ash in various countries.
·         India is at bottom still in utilization of fly ash in concrete
4.6.1.  REACTION MECHANISM OF FLY ASH:
The ability of fly ash to react depends strongly on the alkali content and temperature. The chemical reaction for the fly ash is depends on silica, aluminum oxide, alkali and iron oxide.
                     SiO2 + 2OH = SiO32- + H2O
And that AL2O3 is hydrated according to
                     Al2O3 + 2OH- = 2AlO2- + H2O
That CaO (and MgO) reacts as follows
                      CaO + H2O = Ca2+ + 2OH-
That Na2O (and K2O) reacts as follows
                       Na2O + H2O = 2Na+ + 2OH-
That Fe2O3 reacts as follows
                        Fe2O3 + 3H2O = 2Fe3+ + 6OH-
4.6.2.   ADVANTAGES OF FLY ASH:
The use of fly ash will have a number of performance benefits in concrete, both in fresh and hardened state. Some of these advantages mentioned below:
Reduce water content for a given workability or improves workability for the same water content.
The rate bleeding is reduced.
Fresh mixes pump more easily.
Improves long term strength and durability.
·         Lower shirking and porosity as a result of lower water content.
·         Lower permeability and better resistance to chloride ingress and sulphate attack.
·         Lower heat of hydration.
·         Reduced alkali silica reactivity.
4.7 .  SILICA FUME
Silica fume is a by-product of producing silicon metal or Ferro silicon alloy in smelters using electric arc furnaces. These metals are in many industrial applications include aluminum and steel production , computer chip fabrication, and  production of  silicones, which are widely used in lubricants and sealants. While theseare very valuable materials, the byproduct silica fume is of more importance to the concrete industry replacement of Portland cement due to its versatile properties.  The availability of  high range water reducing admixtures (super plasticizers) has opened  up  new  ideas  for  the  use of micro silica as part of the cementing material in concrete to produce very high strength cement (> 100 Mpa).
Micro  silica  is “ very  fine  non - crystalline  silica  produced  in  electric  arc  furnaces  as a byproduct of  the  production  of elemental silicon or alloys containing silicon”. It is usually a gray colored powder, somewhat   similar to Portland cement or some fly ashes.  Micro silica  is  a  by-product  of  producing  silicon  metal or  ferrosilicon  alloys  in smelters using electric arc furnaces.
Small particle size, high surface area and high silicon dioxide content are the properties ofmicro silica that make it so unique. The average particle size of   micro silica is about 100 to 150 times smaller than the average particle size of Portland cement.
           Reduced Bleeding   because of  the very surface area of the silica fume and the usually very low water content of silica fume concrete, there will  be  very little, if  any  bleeding. Once a silica fume  content of  about  five  percent  is  reached,  there  will  be  no  bleeding  in  most concretes.
4.7.1  CHEMICAL PROPERTIES
Amorphous is simply means that silica fume is not a crystalline material. A crystalline material will not dissolve in concrete, which must occur before the material can react. Don’t forget that there is a crystalline material in concrete that is chemically similar to silica fume. That material is sand. While sand is essentially silicon dioxide (sio2),it does not react because of its crystalline nature.
Micro silica is added to Portland cement concrete  to  improve  its  hardened  properties ,in  particular its compressive strength ,bond strength and abrasion resistance. These improvements stem from both mechanical improvements resulting from addition of a very fine power to the cement paste mix as well as from the pozzolanic reaction between the silica fume and free calcium hydroxide in the paste.
Silicon burnt in the presence of Oxygen gives Silica.
         Si + O2 -SiO2
         C3S (cement) + H2O-CSH+Ca(OH)2
                              The  highly  reactive  silica  reacts with  Calcium hydroxide  released  during the  hydrate  of cement,  resulting  in  the  calcium  silicates responsible for strength.  Addition of silica fume also   reduces the   permeability of concrete to chloride ions, which protects the reinforcing steel of concrete from corrosion, especially in chloride rich environments such   as coastal regions and those of humid continental roadways and runways and saltwater bridges.
4.7.2.  REACTION MECHANISM OF SILICA FUME
 Silicon burnt in the presence of Oxygen gives Silica.
           Si + O2 SiO2
 C3S (Cement) + H2O CSH + Ca (OH) 2
The highly reactive silica reacts with Calcium hydroxide released during the   hydration of
 Cement, resulting in the formation of Calcium Silicates responsible for strength.
              SiO2 + Ca (OH)2  CSH + SiO2
4.7.3.  ADVANTAGES OF SILICA FUME
The use of silica fume will have a number of performance benefits in concrete, both in                   fresh   and hardened state. Some of these advantages mentioned below:
·         Silica fume is a key component of high strength concrete as it contributes to strength at early and later ages.
·         Reduce of concrete permeability.
·         Improvement of concrete sulfate resistance.
·         The ability of C3A cement to complex with chlorides results in the formation of insoluble compound, able to reduce the mobility of free chloride ion to the reinforcement-concrete.
·         Adding more silica fume will usually increase strength.
CHAPTER –5
EXPERIMENTAL PROGRAMME
5.1  OUTLINE PRESENT WORK           
Fly ash (FA) and Silica Fume (SF) is a product confirming to engineering requirements in terms of physical   and chemical properties. So in our present study we are going to put our great diligence in study of  fly  ash (FA) and silica (SF) which can be  made  as a partial cement  replacing  material simultaneously achieving  required  strength  testing  on  mortar  cubes. This study investigated the strength properties of silica fume and fly ash concrete. This work primarily deals with the   strength characteristics such as   compressive, split tensile strength.  High  performance concrete  a set of 6 different  concrete  mixture were cast and  tested  with  different  cement replacement  levels of Fly ash and Silica Fume of M30 Grade namely conventional aggregate concrete (CAC), concrete is made by replacing 15% of cement by Fly Ash and 5% Silica Fume( FASF1),concrete is made by replacing 15% of cement by Silica Fume and 5% of Fly Ash(FASF2), concrete is made by replacing 10% of cement by Fly Ash and 10%Silica Fume (FASF3),concrete is made by replacing of cement by 12% Fly Ash and 8% of Silica Fume (FASF4), concrete is made by replacing of cement by 8% Fly Ash and 12% of Silica Fume(FASF5).
5.2.  EXPERIMENTAL PROGRAMME:
The experimental programme was designed for the mechanical properties i.e. compressive strength, split tensile strength of normal concrete.
The program consists of costing and testing of standard size of cubes. The specimen of standard cubes (150 x 150 x 150 mm), cylinders (150mm diameter 300 mm height), was casted for compression, split tensile strength. The specimens were casted with M30 grade concrete with different replacement levels of cement. Samples was casted and put in normal water curing tank for 7 and 28 days and compressive strength ,split tensile strength were determined and recorded down accordingly.
5.3  SEQUENCE OF OPERATION
             The investigated was carried on M30 grade concrete. The Mix design has been done according to IS: 10262-2009 code method. Required quantities of materials are calculated cement, fine aggregate, coarse aggregate, fly ash, silica fume and water .The coarse aggregate and fine aggregate along with cement are thoroughly mixed mechanically in an electrically operated miller to obtain uniform mix. Then the required percentage of Adhesive materials fly ash and silica fume are added to the above mixed materials. Then the calculated water is added for that particular mix, with a view of obtain uniform mix.
5.4  WORK PLAN
The present experimental programme includes casting and testing of specimens for Compression, Split tensile strength Specimens are prepared for M30 grade of concrete. Total no of  specimens 144  with various percentages of Fly ash and Silica Fume are casted.
     1 .Grades of concrete ( M30)
                                            Normal Water curing

Cubes
Cylinders
 7 days
28 days
7 days
28 days
(CAC)
6
6
6
6
(FASF1)
6
6
6
6
(FASF2)
6
6
6
6
(FASF3)
6
6
6
6
(FASF4)
6
6
6
6
(FASF5)
6
6
6
6
Total
36
36
36
36
Table 5:5.4 Work Plan
Total specimens = 144
5.5  PHYSICAL AND CHEMICAL PROPERTIES OF MATERIALS:
              The fundamental involved in the productive strength of concrete is the selection of material like cement, sand, coarse aggregate etc.  In this study 53 grade Ultratech cement brand of cement was is used. Locally available sand and coarse aggregate were made use of in these study. These materials were tested for their basic properties and the results are tabulated.
5.5.1. CEMENT
          For this present study we have used Ordinary Portland cement (OPC) 53 grade was used. Physical   properties of cement as per IS 8112-1995, and fly ash as per IS4031 (part-II) 1999, are tested at laboratory in the college premises and are presented in the tables.
5.5.2. FLY ASH:
           For this present study we have used fly ash of class F procured from thermal power   station, Hyderabad industrial limited (HIL) ,Hyderabad.
5.5.3 SLICA FUME:
            The silica fume obtained from the ELKEM Pvt Ltd, Bombay confirming to ASTM C1240 was used for this study, Its physical and chemical properties are given in table.
5.5.4. FINE AGGREGATE:
            In this present study we have used sand confirming Zone -II, known from the sieve analysis using different sizes (4.75mm,2.36mm,1.18mm, 600µ,150µ) as per IS: 383-1963 sand passing through 1.18mm sieve . The physical properties of Fine aggregate are shown in tables.
                 
S.NO
   IS Sieve Size
Weight retained
Cumulative weight retained
Cumulatative %weight retained(g)
Cumlatative % passing
1
10mm
0.00
0.00
0.00
100.00
2
4.75mm
10.00
10.00
1.00
99.00
3
2.36mm
46.00
56.50
5.65
94.35
4
1.18mm
188.00
24.50
24.45
75.55
5
600mm
288.00
532.50
53.25
46.75
6
300mm
358.00
890.50
89.005
10.95
7
150mm
109.00
1000.00
100.00
0.00

Table 6: 5.5.4 Analysis of Fine aggregate (Weight of sample 1000g)
                                  Fineness modulus of sand         =   Σg/100
                                    =   273.35/100
                                    =   2.73
5.5.5.  COARSE AGGREGATE:
           In this present study the locally available coarse aggregate are used with maximum size of 20mm confirming to IS 383:1970, the physical properties of Coarse aggregate are shown in tables.
S.NO
Is Sieve size
Weight retained(g)
cumulative retained
cumulative% retained
cumulative % passing
1
80mm
0.00
0.00
0.00
100.00
2
40mm
0.00
0.00
0.00
100.00
3
20mm
3376.50
3376.50
67.52
32.48
4
10mm
1385.00
4761.00
95.22
4.78
5
4.8mm
169.00
4930.00
98.60
1.40
6
2.4mm
70.00
5000.00
100.00
0.00
7
1.18mm
0.00
5000.00
0.00
0.00
8
600mm
0.00
5000.00
0.00
0.00
9
300mm
0.00
5000.00
00.00
0.00
10
150mm
0.00
5000.00
00.00
0.00

Table 7:5.5.5 Sieve Analysis of coarse Aggregate ( Weight of sample 5000 g)
                                        Fineness modulus of Coarse aggregate =  Σg/100
                                                                                            = 361.1/100
                                                                                            = 3.61
               Two concrete mixes were designed for compressive strength and flexural strength of 30MPa with a water cement ratio 0.4 ,as per IS code (456).In both design mixes the Portland cement was replaced by fly ash and silica fume and the specimens are casted.
5.5.6  WATER
                The water used for the study was free of acids, organic matter, suspended solids, alkalis and impurities when present may have adverse effect on the strength of concrete Potable water with PH value of 7.0 confirming to IS 456-2000 was used for making concrete and curing this specimen as well.
5.5.7  BLENDED CEMENT
SF and FA blended cements were prepared by replacing OPC with combination of SF and FA blended cement were prepared by replacing OPC with different of SF+FA by weight of cement. The blended cement was prepared in dry condition.
5.6  MIX PROPORTIONS AND CASTING PERFORMANCE CONCRETE SPECIMEN.
5.6.1.  MIXING:
Manual mixing is adopted throughout the experimental work. First the materials cement, Fly ash, Silica Fume, fine aggregate, coarse aggregate are weighed exactly. First the cement, Fly ash and Silica Fume are blended with hand and then fine; coarse aggregate is added to this and thoroughly mixed. Water is weighed exactly and added to the dry mix and entire mix is thoroughly mixed till uniformity is arrived.
Fig.4 Mixing Materials For Casting Concrete Specimens
5.6.2:  Casting of Specimens:
For casting the cube, standard Cast iron metal moulds of size 150x 150 x 150mm have been used. Whereas cylinders and prisms of size 150x300mm  are casted respectively. The moulds have been cleaned of dust particles and applied with mineral oil on all sides, before concrete is poured into the mould. Thoroughly mixed concrete is filled in to mould. Whole casting procedure is confined to Indian Standard: 10086-1882.
Fig.5  Casting of concrete cubes
5.6.3  PLACING AND CURING:
After casting, the moulded specimens are stored in the laboratory free from vibration, in moist air and at room temperature for 24 hours.After this period, the specimen are removed from the moulds and immediately submerged in the clean fresh water of curing tank. Every three to four days the water is removed from water sump and placed with fresh water to avoid any chemical reaction of water.
Fig.6  Normal water curing
 5.7   TESTING PROGRAMME
5.7.1  SLUMP CONE TEST
               Slump cone test is very common test for determination of workability of concrete. This test was carried out in both mix cases i.e., M30 before casting the cubes, cylinders . The slump cone test was measured in mm, as shown in photograph.
Fig.7 Slump Cone Test
SLUMP MESURMENT
5.7.2  COMPRESSIVE STRENGTH OF CONCRETE
           Compressive   strength   combination of SF and FA blended cement Concrete cube   was determined as per IS9013-1997 after 7, and 28 days of moisture curing.
5.7.3  SPLITTING  TENSILE STRENGTH OF CONCRETE
            Splitting   tensile strength   test was conducted   on   combination of   SF and FA blended concrete cylinder as per IS 5816-1999 after 7 and 28 days of moisture curing.
5.8.  TEST FOR COMPRESSIVE STRENGTH OF CONCRETE
After 7 and 28 days of curing the casted cube specimens were removed from the water   sump and placed on flat surface for 15 to 20 minutes to wipe off the surface water and grit, and also remove the projecting fineness on the surface of the cured cubes. On the date of testing i.e. after 7,28 days testing is done. Before placing the cubes in compression testing machine the bearing  surfaces  (top and bottom) of the compression testing machine was wiped  clean with a piece of cotton or fine brush, and the cube specimens also cleaned. The cube specimen was placed in the compression testing machine (CTM) of 2000KN capacity.
         The applied load is   gradually   increased until the cube is failed. The maximum   load   is recorded when the cube was collapsed. The compressive strength of cube was calculated  by dividing the maximum load   applied on the specimen  during the test  by the cross  sectional area  of the  specimen  for which  average of three values of  three  cubes and  the  individual variation is more than 15%  of  the  average  was  observed. The test results are presented in Table.
Compressive strength (C) = P/A.
Compressive strength(C) = Load/Area
Where, P = maximum applied load in Newtons
A = Area of cross section of cube in mm2   (150mm x 150mm)
Fig.8  Tests for Compressive Strength of Concrete
5.9.  TEST  FOR SPLIT TENSILE   STRENGTH OF CONCRETE
It is the standard test, to determine the tensile strength of concrete in an indirect way. This test could be performed in accordance with IS:5816-1970. Astandard test cylinder of                 concretespecimen (300mm height, 150mm diameter) is placed horizontally between the loading surfaces of compression testing machine. The compression load is applied.
Diametrically and uniformly along the length of cylinder until the failure of the cylinder longthe vertical diameter. To allow the uniform distribution of this applied load and to reduce themagnitude of the high compressive stresses near the points of application of this  load, strips of plywood  are placed between  the specimen  and loading  platens  of  the testing   machine. Concrete cylinders split into two halves along this vertical plane due to indirect tensile stress generated by poison’s effect.
              Due to the tensile loading, an element lying along the vertical diameter of the cylinder is subjected to vertical compressive stress and a horizontal stress. The  loading   condition produces   a high compressive stress immediately below the loading points. But the larger portion of cylinder, corresponding to its depth is subjected to uniform tensile stress acting horizontally.  It is estimated that the compressive stress is acting for about 1/6depth and  the remaining 5/6 depth is subjected to tension due to Poisson’s effect.  Assuming   concrete specimen behaves as an elastic body. A uniform lateral tensile stress of  ft  acting along  the vertical  plane causes  the failure of  the  specimen,  which can  be calculated  from the formula as,
ft = 2p/πld
ft =Split tensile strength
                             p = Compressive load at failure
                             l = Length of cylinder
                            d = Diameter of cylinder
Fig.9  Tests for Split Tensile Strength of Concrete
 CHAPTER –6
DISCUSSION OF TEST RESULTS
6.  DISCUSSIONS OF TEST RESULTS
                   The experimental program was designed to investigate silica fume and fly ash as partial replacement in concrete. The replacement levels of cement by silica fume and fly ash are selected as (0%, 5%, 8%, 10%, 12%, and15%) and (0%, 5%, 8%, 10%, 12%, and15%) by weight of cement for standard size of cubes. The specimen of standard cube(150mmx150mm x 150mm), cylinders (150mm diameter 300height), and prism (100 x 100 x 400mm) was casted for compression, split tensile strength and flexure test.
6.1. COMPRESSIVE STRENGTH OF CONCRETE
                 The cube compressive strength results of Concrete mixes at ages of 7, 28 days arepresented in table .The development of compressive strength of M30 grade of concrete mixes containing 0,5,8,10,12,and15 percent of silica fume and 0,5,8,10,12,and15 percent of fly ash at the various stages of normal curing.
                    The maximum compressive strength of concrete in combination with fly ash and silica fume depend on two parameters namely the replacement levels and water cement ratio. And the compressive strength is varying with days also. The results and graphs as shown in below table and graphs.





6.1.1  COMPRESSIVE STRENGTH  RESULTS:
           Table 8:6.1.1  Compressive Strength Results for Normal Water Curing.

MIX

7 DAYS STRENGTH

28 DAYS STRENGTH

CAC

26.31MPa

40.47 MPa

FASF1

23.68 MPa

36.88MPa

FASF2 

24.70MPa

38.00MPa

FASF3

25.86 MPa

39.79MPa

FASF4 

21.50 MPa

33.08 MPa

FASF5  

19.52 MPa

31.65 MPa
CAC = 100% OPC
FASF1  = 15% FA + 5% SF                                              FASF2 = 5% FA +15%SF 
FASF3=   10% FA + 10% SF                                            FASF4 = 12% FA + 8% SF
FASF5 = 8% FA + 12% SF 



COMPRESSIVE STRENGTH RESULTS AS SHOWN IN BELOW:
        
Graph.1 Compressive strength for Normal water curing 
  
CAC = 100 % OPC
FASF1  = 15% FA + 5% SF                                                         FASF2 =     5% FA +15%SF 
FASF3=   10% FA + 10% SF                                                       FASF4 = 12% FA + 8% SF
FASF5 =   8% FA + 12% SF 

6.2.1 SPLIT  TENSILE  STRENGTH  RESULTS:
            The splitting tensile strength combination of FA and SA blended concrete after 7days and 28 days curing are shown in fig. According to that my result 10% FA and 10%SF are replaced by cement can be reached the CAC strength value.



6.2.1 SPLIT TENSILE STRENGTH RESULT FOR NORMAL CURING OF WATER:

MIX

7 DAYS STRENGTH

28 DAYS STRENGTH

CAC

2.88 MPa

               4.44 MPa

FASF1

2.47 MPa

              3.99 MPa

FASF2

2.60 MPa

4.30 MPa

FASF3

2.67 MPa

             4.42 MPa

FASF4 

2.17 MPa

3.34 MPa

FASF5

2.09 MPa

3.18 MPa

CAC = 100% OPC
FASF1  = 15% FA + 5% SF                                                         FASF2 =     5% FA +15%SF 
FASF3=   10% FA + 10% SF                                                       FASF4 = 12% FA + 8% SF
FASF5 =   8% FA + 12% SF 


a)  Split tensile strength results for Normal curing of water as shown in Graphs and Bar Charts:

Graph.2 Split Tensile Strength Result For Normal Curing of water

                                                                                                                                           
CAC= 100 % OPC
FASF1  = 15% FA + 5% SF                                                         FASF2 =     5% FA +15%SF 
FASF3=   10% FA + 10% SF                                                       FASF4 = 12% FA + 8% SF
FASF5 =   8% FA + 12% SF 



CHAPTER –7
CONCLUSIONS
Based on experimental studies   the following conclusions are drawn.
The following conclusions are drawn from the experimental investigation in present project:

1               The combination of (10% Fly Ash+ 10% Silica Fumes) performed the best among all the ternary mixes at 7days, 28 days respectively.

2               The combination of (8% Fly Ash+ 12% Silica Fumes) will give the least Compressive Strength and split tensile strength among all the ternary mixes of M30 grade concrete.

3               Compressive strength and split tensile strength of Ternary Blended Concrete for (10% Fly Ash+ 10% Silica Fumes) combination is varied from 25MPa to 39MPa and 2.60 MPa to 4.42 MPa at 7 and 28 days.

4               The percentage increase in compressive strength and split tensile strength of Ternary Blended Concrete is found to be higher at higher ages for all the ternary mixes.

5               The fineness of Silica fumes is almost nearer to the cement so it acts like a pozzoloanic behaviour.

6               The improved performance of Micro Silica concrete could be attributed to the improvement in bond between the hydrated cement matrix and aggregate. This in turn is due to the combined effect of secondary pozzoloanic reaction and the fineness of Micro Silica particles.


7               In micro silica of its pozzoloanic reactivity, improves the bond of aggregate paste interface, thus it increases the strength of concrete. The dense microstructure of fly ash improves the bond strength of concrete.

8               Triple blending of cement with micro silica and fly ash proved to be cost effective and eco friendly without loss in strength of concrete.


9               Results show that Ternary Blended Concrete offer significant advantages over Ordinary concrete. Such Concretes show generally good properties and offset the problems associated with using fly ash and Micro Silica when these materials are used individually.

10           In ternary blended concrete micro silica act as filler and fly ash controls the workability Therefore, this combination is more effective in improving the properties of ternary blended concrete.
7.2.  SCOPE OF FURTHER STUDY:
The experimental work on pozzolanic materials along with ordinary Portland cement is still limited. But it has a great scope for further studies.
The following aspects are considered for future study and investigations.
1.      Industrial wastes, such as silica fume, blast furnace slag, fly ash are being used as supplementary   cement replacement materials and recently, agricultural wastes are also being used as pozzolanic materials in concrete.
2.      To reduce the green gas emission and to safe the land.
3.      It is requires a proper mixing proportions for the development of high strength, high performance concrete which may not be possible manually. So its need some global optimizations technique to develop the desired results with greater accuracy and time saving.

APPENDIX
               Sample calculation for M30 grade of concrete
1. DESIGN STIPULATIONS
Characteristic compressive strength required
In the field at 28 days                                  30 N/mm2
Maximum size of aggregate                        20 mm (angular)
Degree of workability                                  medium
Degree of quality control  Good 
Type of exposure                                          mild
2. TEST DATA OF MATERIALS
Cement                                                        53 Grades OPC
Specific gravity of cement                          3.02
Specific gravity of CA                                2.59
Specific gravity of FA                                 2.60
1.      TARGET MEAN STRENGTH OF CONCRETE   
      (from Table 1 & Table 2 of IS: 10262-2009)
Ft = ƒck + 1.65 S
For M30 grade Standard Deviation, s = 5 N/mm2
    = 30 + 1.65 × 5.0
    = 38.25 N/mm2
2.      SELECTION OF W/C RATIO   
      (from Table 5 of IS 456)
W/C ratio = 0.48
5. SELECTION OF WATER CONTENT   (from Table 2 of IS: 10262-2009)
Maximum water –cement ratio = 186 liters (for 25 to 50mm slump range)
Water content = 170.5 kg/m3
3.       DETERMINATION OF CEMENT CONTENT
Water-cement ratio = 0.48
Water content= 170.5 liters
Quantity of cement = water content
                                          W/c
= 170.5/0.48
= 355.21 kg/m3
4.      PROPORTION OF VOLUME OF F.A & C.A CONTENT    
(from Table 3 of IS:  10262-2009)
Volume of coarse aggregate for the water cement ration = 0.62
7.1  MIX PROPORTIONS
a) Volume ofconcrete                                           = 1m3
b) Volume of Cement                                           = (355.21/3.02) X (1/1000)
                                                                              = 0.1176 m3
c) Volume of all Aggregate                                  = [a-(b + c + d)]
                                                                              = 1-(0.1176+0.170+0)
                                                                              = 0.7119 m3
d) Mass of coarse aggregate                                 = 0.727x0.62x2.59x1000
                                                                              = 1167.42 kg.
e) Mass of fine aggregate                                      = 0.727x0.38x2.60x1000
                                                                              = 718.28 kg
Mix proportion:
Cement        :    Fine Aggregate        :    Coarse Aggregate     :   Water
    355.21      :        718.28                   :          1167.4                  :   170.5
     1              :       2.05                        :         3.2865                   :   0.48
RFFERENCES
1)      A.K. Mullick. “Performance of Concrete with Binary and Ternary cement blends”. The INDIAN Concrete Journal, January 2007.

2)      Deepa A Sinha “Comparative mechanical properties of different ternary blended concrete”, Indian Journal of Research,pg:65-69 Volume : 1 | Issue : 10 | October 2012, ISSN - 2250-1991

3)      Md. Rezaul Karim 1, Md. Maruf Hossain 2, Mohammad NabiNewaz Khan 2, Muhammad FauziMohd Zain 2 and FookChuan Lai 3On the Utilization of Pozzolanic Wastes as an Alternative Resource of CementMaterials2014, 7, 7809-7827;

4)      M.G.Alexander, B.J.Magee. “Durability performance of concrete containing condensed Silica fume”. Cement and concrete Research 29 (1999) Pg 917-922.

5)      P. Murthi and V. Sivakumar, “Studies on Acid Resistance of Ternary Blended Concrete.” Aisan Journal of Civil Engineering (BUILDING AND HOUSING) VOL. 9, NO. 5 (2008)pages 473-486.
1. TEXT BOOKS
    1) N.Krishna Raju,”Design of Concrete Mixes”,Year 2005
    2) A.M.Nevile,”Properties of concrete”ELBS with Longman 1987
    3) M.S.Shetty,”Concrete Technology”, Year 2008
    4) A.R.Santhakumar,”Concrete Technology”, Year 2011
    5) M.L.Gambhir,”Concrete Technology Theory and Practice”, Year 2012
    6) Concrete technology by M.S.Shetty.

2.  IS CODES
     1) IS 456-2000 code of practice for plain & reinforced cement concrete.
    2) IS 10262-2009 recommended guide line for concrete mix design.
    3) IS 9103-1999 Concrete admixture-specification.
    4) IS 12269-1987 Specification for OPC 53 grades.
    5) IS 383-1970 Specification for coarse aggregate and fine aggregate from natural sources.
    6) IS 650-1966 Specification for standard sand for testing of cement.