Application of biomineralisation for enhancement of interfacial properties of rice husk ash blended concrete

Abstract

The present study is comprehensive research on application of biocementation to enhance the properties of concrete including rice husk ash (RHA) as a supplementary cementitious material (SCM). RHA has a large potential to be used as SCM because it has high silica content which eventually forms C–S–H gel by reacting with calcium and water, which increases strength of the cementitious material. However, using high doses of RHA causes a decrease in concrete strength because excessive silica is available to react with calcium hydroxide, forming silica clumps within the concrete matrix, which reduce the bonds within the concrete constituents causing micro cracks. Hence to mitigate this problem, enzyme induced calcium carbonate precipitation (EICCP) process was used to treat the micro cracks, and enhance the mechanical and durability properties of RHA blended concrete. Results showed that EICCP process enhanced the strength of the mix at each replacement level and 10% replacement level exhibited optimum results. with nearly 29% increment in compressive strength. This mix also exhibited enhanced durability as compared to the control specimens. Since concrete constitutes a significant portion of embodied carbon footprint, using greener concrete mixes like “Experimental Mix” has the potential to considerably decrease the carbon footprint of construction.