Behaviour of Fly Ash and Rice Husk Ash Based Geopolymer Concrete

Geopolymer Concrete (GPC) is a novel concrete which has evolved in recent decades. It uses industrial waste products like fly ash (FA), ground granulated blast slag (GGBS), Rice husk ash (RHA), micro-silica, and red mud etc., from industries, with alkaline liquids to replace cement in concrete by 100%, thereby developing an eco-friendly and sustainable construction material and simultaneously reducing waste disposal problem of fly ash and rice husk ash. GPC not only possesses excellent mechanical properties it also have very good durability properties. This paper presents the effect of partial replacements of fly ash with rice husk ash on the properties of geopolymer concrete. Mixes chosen for investigation were GPC-1, GPC-2, GPC-3, GPC-4, and GPC-5 containing respectively 0%, 5%, 10%, 15%, and 20% RHA in place of FA. Various synthesis parameters like alkaline liquid to source material ratio, molarity of NaOH solution, sodium silicate to sodium hydroxide ratio were kept at their optimum values of 0.45, 12M, and 2.5 respectively. Heat curing was given to specimens by dry oven curing for initial 24 hours at a specified temperature of 70°C, and then ambient exposure was given to the test specimens for periods of 3, 7, 28, and 90 days respectively. Results of tests conducted have been discussed in detail.