An experimental study on behaviour of concrete by using combination of GGBS with rice husk ash and comparing it with the conventional concrete

Abstract

The paper presents an experimental investigation on behaviour of the concrete by replacement of cement with GGBS ( 20%, 50% ,70%,80%,90% by weight of cement ) and replacement of sand with rice husk ash (2% ,5% by weight of the sand) and controlled specimen like cubes, cylinders were casted .The compressive strength and split tensile strength of the cubes and cylinders respectively were found out for mix design M20 & M40 for various replacement combination such as (GGBS 20%+ RHA 2% , GGBS 20% + RHA 5% , GGBS 50% + RHA 2% , GGBS 50% + RHA 5% , GGBS 70% + RHA 2% , GGBS 80 % + RHA 2% , GGBS 90% + RHA 2%). Tests were done for 7 days, 14 days, 28 days and comparison is done with various proportions say M20 & M40 mixes. For the above mentioned replacement and find out the optimum results for the replacement. Slump is found out for the various mixes and decides the dosage of the super plasticizer without changing the water cement ratios. Higher dosages of super plasticizer have been used to achieve the required workability for M40 mixes especially 5% Rice husk ash replacement. From the test result it has been observed that increase in the percentage of the rice husk ash leads to decrease in the strength. Slight variations shown for the results in 2% addition found that the replacement for the sand find effective optimum. GGBS 20% and 50% replacement along with 2% rice husk ash had shown almost the same result. Hence fixing 2% replacement with higher replacement of GGBS to find the optimum, and the optimum results found in phase 2 shows GGBS 20% replaces cement and Rice husk ash 2% replaces sand shows best result. Split tensile strength test done were also done and shows the same replacement bears the best result. Acid test was conducted with the optimum replacement shows higher resistance to sulphate and acid attack. Flexural test was also done with optimum replacement mix on beams shows that there is slightly higher load carrying capacity than the nominal mix beam. Deflect meter reading shows that there is not that much difference in young’s modulus of the both the mix.