Preliminary study of cement paste admixed with rice straw ash, microsilica & rice straw ash-microsilica composite

Abstract

The objective of this study was to examine pastes in order to check the possibility of utilizing unprocessed rice straw ash with or without micro silica in Pavement Quality Concrete. Physical (SEM, XRD, Specific Gravity etc.) & chemical properties (XRF) of materials used were analyzed. Different proportions of OPC, RSA & Micro silica were researched for normal consistency, initial and final setting time of paste etc. Different proportion of rice straw ash and microsilica used for part replacement of OPC in the cement paste were 5, 10, 15, 20, 25, 30% and 2.5, 5, 7.5, 10% by weight of OPC respectively. Rice straw ash was also mixed with micro silica to form a composite for replacing OPC in the mix. Mix R1M3 (5% Rice Straw Ash & 7.5% Micro Silica) could achieve highest pozzolanic reaction while mix R2M3 (10% Rice Straw Ash & 7.5% Micro Silica) could achieve maximum economy. In India, Rice Straw is produced in abundance and has extensive geographical coverage. Rice Straw Ash is technically of no use to farmers, and they treat it as a waste product. They tend to burn rice straw in order to clear their field for the next batch of crop. In this paper, rice straw admixed with micro silica is treated as a potential material for pavement construction, and various preliminary tests were done on cement-rice straw ash-micro silica paste to check the possibility of using rice straw ash in pavement quality concrete.