Mechanical and Durability Properties of Self Compacting Concrete Containing Rice Husk Ash

Abstract

Self-compacting concrete (SCC) is relatively a recent development in the construction world. SCC is defined basically by two properties: Deformability and segregation resistance. It flows under its own weight while remaining homogeneous in composition. This research is aimed at examining the feasibility of using Rice Husk Ash as supplementary cementitious material. In this research, the main variables are the proportion of rice husk ash (0%, 10%, 15%, 20%) and cement content. Parameters kept constant are the amount of fine aggregates, coarse aggregates, water, SP content, w/b ratio. The primary aim of this study is to explore the feasibility of using rice husk ash as supplementary cementitious material in SCC by examining its fresh properties, mechanical properties (compressive strength, splitting tensile strength), durability properties (porosity, rapid chloride permeability), along with microstructure analysis with XRD and SEM. The test results revealed that the fresh properties were significantly influenced by rice husk ash content. All the results were in range as per code specified. Mix 20RHA showed minimum workability.. The increase of about 25% strength at 7 days, 33% strength at 28 days and 36% strength at 56 days were observed with increase of RHA content from control mix (0RHA) to 15RHA. Maximum splitting tensile strength was also obtained by the mix 15RHA. Greatest increase in mechanical properties was observed for the mix containing 15% rice husk ash. The inclusion of rice husk ash as replacement of cement does not affect the strength properties negatively as the strength remains within limits up to 20% replacement. Inclusion of RHA showed great improvement in durability properties of concrete. All the mixes were less porous as compared to controlled mix with 0% rice husk ash and they showed low chloride penetration also. Microstructure of 15RHA mix shows dense formation of C-S-H gel that is the root cause for increase in strength.