EFFECT OF CHEMICAL ADMIXTURES IN HIGH STRENGTH CONCRETE

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1 EFFECT OF CHEMICAL ADMIXTURES IN HIGH STRENGTH CONCRETE P.Jagadeesh 1 and S.khaviya 2 1,2 Department of civil engineering, Kongu engineering College Abstract This project deals with the experimental study on effect of chemical admixtures in M grade of concrete. Now a days there is a rapid increase in the infrastructure development which in turn demands lesser construction time and labour. In this objective, precast structures are used in construction and are proved to be an economic alternative. In precast, the concrete elements are casted in industry, it requires early strength for early demoulding for increasing the production capacity. With the said requirement as objective, in the present study, we are using various chemical admixtures namely, Rheobuild 1100 (flowable concrete, with a low water / cement ratio), Glenium Ace 30 (suitable for SSC), Sika Viscocrete 20 He C (accelerate cement hydration), Ecmas Hp-901(P), Varaplast Pc 100 (stabilizers the mixes due to static repulsion of long lateral chains linked to the polymer backbone), in M grade of concrete to determine its effect in concrete, early strength development properties at a chosen lower water-cement ratio. The results are then analyzed critically for its comparative study and inferences are to be made accordingly. Keywords High strength concrete, chemical admixtures, water cement ratio, workability, steam curing, early strength. I. INTRODUCTION The construction of modern days have become fast track where the economics on the investment on the form work are considered the use of high strength concrete is invariable and has become a must. Addition of chemical admixtures to concrete can be very useful for easy handling and attaining better strength. In HSC the least costly components of conventional concrete are basically eliminated or replaced by more expensive elements, which is a drawback of it. By using chemical admixtures we can control the cost of high strength concrete. Admixtures not only in part early strength and concrete and enhance workability of concrete but also reduces the quantity of cement required in concrete and makes it economical. As we know admixtures are added in RMCs in order to accelerate or decelerate setting time of concrete sometimes it also access anti-bacterial agents. Chemical admixtures can maximize the sustainability of concrete by using waste products into it. II. OBJECTIVES AND PPRINCIPLES 2.1 OBJECTIVES: This study has the following objectives To study on effect of adding several chemical admixtures for making easy placement of concrete mixtures even with low water- cement ratio. To increase the workability level at a given water- cement ratio. To reduce the setting time of concrete for increasing the production capacity. 2.2 PRINCIPLES FOR DEVELOPING HIGH STRENGTH CONCRETE: By reducing porosity, in homogeneity, and micro cracks in the hydrated cement paste and the transition zone in concrete can produce high strength in high strength concrete. DOI: /IJMTER RS2GK 183

2 International Journal of Modern Trends in Engineering and Research (IJMTER) The optimal usage of chemical admixtures is to reduce the water content in concrete and improve workability. The workability of fresh concrete is improved and allows the concrete producer to reduce the water cement ratio, thus increase the strength of the Concrete. Consequently, there is a reduction of the thickness of the interfacial transition zone in High Strength Concrete. III. CHEMICAL ADMIXTURES 3.1 HIGH RANGE WATER-REDUCERS (HRWR) It is a special water-reducer, usually called superplasticizers. HRWR are capable of reducing the water content of a given concrete mixture from 12% to 25%. Reduction of water content in the mixture and increasing the slump to produce flowing concrete without adding watere two main mechanism of HRWR used in order to increase strength and reduce permeability of concrete. These admixtures must be added to high strength concrete mixtures because they contain high amount of cementitious materials. For example, addition of a normal dosage of High Range Water-Reducer to a concrete with a slump of 3 to 4 inches can develope a concrete with a slump of about 8 inches (200 mm). Some High Range Water-Reducers may cause a higher rate of slump loss with time and concrete may revert to its original slump in 30 to 45 minutes. In some cases, High Range Water-Reducers may be added at the jobsite in a controlled manner. 3.2 ADVANTAGES OF REDUCING WATER CONTENT Increased strength Lower permeability Increased resistance to weathering Better bond between concrete and reinforcement Reduced drying shrinkage and cracking 3.3 LIST OF CHEMICAL ADMIXTURES USED IN THE STUDY Rheobuild 1100 Glenium Ace 30 Sika Viscocrete 20 HE C Ecmas Hp-901 (P) Varaplast Pc 100 IV. MIX DESIGN The mix design for this study is as follows: The water cement ratio should be as less as possible. Table.1 Mix Design Ordinary Portland Cement(53 grade) 430 kg 20 mm Coarse Aggregate 625 kg 12 mm Coarse Aggregate 515 kg River Sand Crushed stone sand Water Chemical Admixtures 432 kg 238 kg Water-Cement ratio Litres 3 to 3.5 All rights Reserved 184

3 International Journal of Modern Trends in Engineering and Research (IJMTER) 4.1 MIXING AND PLACING Concrete was mixed by mixer machine. Initially for 45 seconds the dry ingredients are mixed thoroughly for homogeneous mix without adding water and chemical admixture. Then the 70 % of the mixing water is added for wet mix and the remaining 30 % of water is added with the chemical admixture along with the wet mix, then a revolution time of 100 seconds is allowed for homogeneous wet mix of concrete. The chemical admixture should not be added to the dry ingredients of concrete. The workability of the concrete is measured by Slump test. Hence High Range Water Reducing (HRWR) chemical admixture are used in concrete due to that there will be a significant slump loss with time. 4.2 ADMIXTURE DOSAGE LEVEL Table.2 Admixture dosage level ADMIXTURE NAME DOSAGE LEVEL RHEOBUILD % of cementitious material GLENIUM ACE % of cementitious material SIKA VISCOCRETE 20HE C 0.55 % of cementitious material VARAPLAST PC % of cementitious material ECMAS HP-901(P) 0.55 of cementitious material V. RESULT AND DISCUSSION 5.1 SLUMP VALUE FOR VARIOUS CHEMICAL ADMIXTURES Table.3 Slump value for various Chemical admixtures Chemical admixture name Slump Value in mm Rheobuild Glenium Ace Sika Viscocrete 20 HE C 150 Ecmas Hp-901 (P) 150 Varaplast Pc Conventional concrete (No admixture) COMPRESSIVE STRENGTH The compressive strength of concrete with different admixtures dosage are tested with five cubes each with cube size of 150*150*150 mm. this value determines the overall strength and efficiency of the concrete and test results are listed All rights Reserved 185

4 International Journal of Modern Trends in Engineering and Research (IJMTER) Table.4 Average compressive strength of concrete with and without admixture NAME OF ADMIXTURE 12 HOURS 3 DAYS 7 DAYS 14 DAYS 28 DAYS Rheobuild Sika Viscocrete 20 He c Ecmas Hp 901 (P) Glenium Ace Varsplast Pc Conventional concrete [without admixture] COMPARITION OF STRENGTH OF CONVENTIONAL CONCRETE WITH VARIOUS ADMIXTURE CONCRETE RHEOBUILD 1100 Table.5 Comparing the Compressive strength between Conventional Concrete Vs Rheobuild 1100 Conventional Concrete (Mpa) Rheobuild 1100 (Mpa) 12 Hours Figure 1 Graphical comparisons of Compressive Strength between Conventional Concrete Vs Rheobuild All rights Reserved 186

5 Compressive Strength (Mpa) International Journal of Modern Trends in Engineering and Research (IJMTER) SIKA VISCOCRETE 20 HE C Table.6 Comparing the Compressive strength between Conventional Concrete Vs Sika Viscocrete 20 He C Conventional Concrete (Mpa) Sika Viscocrete 20 He C (Mpa) 12 Hours Conventional Concrete Vs Sika Viscocrete 20 He C Hours Conventional Concrete Sika Viscocrete 20 He C Figure 2 Graphical comparison of Compressive strength between Conventional Concrete Vs Sika Viscocrete 20 He C ECMAS HP 901 (P) Table.7 Comparing the Compressive strength between Conventional Concrete Vs Ecmas Hp 901 (P) Conventional Concrete (Mpa) Ecmas Hp 901 (P) (Mpa) 12 Hours All rights Reserved 187

6 Compressive Strength (Mpa) Compressive Strength (Mpa) International Journal of Modern Trends in Engineering and Research (IJMTER) Conventional Concrete Vs Ecmas Hp 901 (P) Hours Conventional Concrete Ecmas Hp 901 (P) Figure 3 Graphical comparison of Compressive Strength between Conventional Concrete Vs Ecmas Hp-901 (P) GLENIYM ACE 30 Table.8 Comparing the Compressive strength between Conventional Concrete Vs Glenium Ace 30 Conventional Concrete (Mpa) Glenium Ace 30 (Mpa) 12 Hours Conventional Concrete Vs Glenium Ace Hours Conventional Concrete Glenium Ace 30 Figure 4 Graphical Comparisons of Compressive Strength between Conventional Concrete Vs Glenium Ace All rights Reserved 188

7 Compressive Strength (Mpa) International Journal of Modern Trends in Engineering and Research (IJMTER) VARAPLAST PC 100 Table.9 Comparing the Compressive strength between Conventional Conventional Concrete (Mpa) Varaplast Pc 100 (Mpa) 12 Hours Concrete Vs Varaplast Pc 100 Conventional Concrete Vs Varaplast Pc Conventional Concrete Varaplast Pc Hours Figure 5. Graphical Comparison of Compressive Strength between Conventional Concrete Vs Varaplast Pc 100 VI. CONCLUSION Based on the experimental investigations carried out the following conclusions are made:- The Chemical admixtures used for the concrete are High Range Water-Reducers hence they achieve early high strength in the period of 12 hours. Here we used various chemical admixtures in concrete and compared the strength with the conventional concrete. When using chemical admixtures in concrete the workability of the concrete is improved under lower water-cement ratio, when compared All rights Reserved 189

8 International Journal of Modern Trends in Engineering and Research (IJMTER) conventional concrete where the water-cement ratio is high. Steam curing system is required for achieving even more high early strength of the concrete. REFERENCES [1] M. K. Maroliya, Influence Of Type Of Chemical Admixtures On Sand And Cement Content Of Ordinary Grade Concrete International jounrals of advance in engineering and technology,2012. [2] P. Vijay Prabhu, S. Arther Prabhakar, R. Iyappan and M. Murugan, Experimental Study On Mortar Using Natural Admixtures, International Journal of Scientific & Engineering Research,Vol. 7, Issue 5, [3] J.A. Naqash, Zahid Bashir Bhat, Mohammad Iqbal Malik, Subzar Ahmad, Dharvinder Kumar, Effect of Accelerating Admixture on Properties of Concrete, IOSR Journal of Engineering,Vol. 04, Issue 03, PP 48-55, [4] Dinesh Kumar, Sugarcane Molasses in Concrete as a Water Reducing-Retarding Admixture: A Review, SSRG International Journal of Civil Engineering, PP , [5] Jay H Shah, Sachin B Shah, Comparative Study of Concrete Mix Design by Adding Various Types of Admixtures,International journal of engineering development and research.volume 2, Issue 3, [6] Suhad M Abd, Qasssim Y Hamood, Alaa S Khamees and Zainab H Ali, Effect Of Using Corn Starch As Concrete Admixture, Int. J. Engg. Res. & Sci. & Tech, Vol. 5, No. 3, [7] S.Karthikeyan, A.A.Elangovan, Experimental Study of Ancient Admixture and Natural Fiber in Concrete, Vol.4, IJRET: International Journal of Research in Engineering and TechnologyIssue- 12, [8] Anitha J, Pradeepa S, Lalit Soni, Rakshit K. B, Influence of Admixtures on Behavior of Concrete, International Journal of Research in Advent TechnologyVol.4, No.11, [9] Saandeepani Vajje, Dr.N.R.Krishna murthy, Study on Addition of the Natural Fibers into Concrete, International Journal of Scientific & Technology Research, Vol. 2, ISSUE 11, [10] Afef Makni, Mohamed Jamel Rouis, Impact of the Addition of Colloidal Admixture Properties When Cured Self Compacting Concrete Used in Bored Piles in Sludge, IOSR Journal of Mechanical and Civil Engineering Vol. 12, Issue 2, PP , All rights Reserved 190