Effect of Colloidal Nanosilica on High Strength Rice Husk

Abstract

Nowadays, supplementary cementitious materials (SCMs) are used in concrete because it reduces CO2 emission during. The husks, which are production of cement, reduces cement contents, improve workability, increase strength and enhance durability. Pozzolanic reaction takes place when siliceous or aluminous material comes in contact with calcium hydroxide in the presence of moisture to form compounds possessing cementitious properties approximately 50 percent cellulose, 30 percent lignin and 20 percent silica, are incinerated by controlled combustion leaving behind an ash that predominantly consists of amorphous silica. Rice husk ash is highly pozzolanic due to its extremely high surface area (50,000 to 100,000 m2/kg). The colloidal nano silica (CNS) which is nano material and behaved not only as a filler to improve cement micro-structure (porosity decrease), but also as a promoter of pozzolanic reaction used in cement for accelerating pozzolanic action due to which the cement sets faster than conventional mix. In the present study, the mineral admixture, rice husk ash (RHA) was used as 5, 10, 15% replacement for OPC in M60 grade of concrete. The 10% RHA was taken as optimum dose on the basis of workability and compressive strength. To this 10% RHA concrete, effect of 1, 2, 4, and 6% CNS addition were experimentally studied with various properties like workability, compressive strength and split tensile strength.