Feasibility Studies on Compressive Strength of Ground Coal Ash Geopolymer Mortar

Abstract

Coal ash obtained from the Thermal Power plants consists of a major portion of Flyash and less amount of Bottom ash. As a major portion of the coal ash, fly ash has been recognized widely as a source material for geopolymers while the utiliza-tion of bottom ash has received very less attention owing to its coarser size.Hence to promote greater utilisation of bottom ash in construction sector, this work proposes the use of ground bottom ash in geopolymer mortar. The effect of molar ratio of SiO 2 /Na 2 O, Na 2 SiO 3 /NaOH ratio and curing mode were studied on compressive strength of coal ash geopolymer mortar. Molar-ity of sodium silicate solution was kept as 8M. Ambient curing and steam curing at 60ºC was attempted. Test results indicate that Na 2 SiO 3 /NaOH of ratio 2 with SiO 2 /Na 2 O molar ratio 1 mortar achieved higher compressive strength under both ambi-ent curing and steam curing.