Rice Husk Ash and Basalt Fibre-Based Sustainable Geopolymer Concrete in Rigid Pavements Under Ambient Curing Conditions

In this study, the rice husk ash (RHA), which is a by-product of paddy, was used as source material in geopolymer concrete in the presence of alkaline activator primed by assimilation of sodium hydroxide and sodium silicate. Basalt fibres, which are the derivative of basaltic rock or volcanic eruption, were used as fibre reinforcement in geopolymer concrete. Rice husk ash rich in silica and basalt fibre rich in alumina proved better combination. The sodium silicate-to-sodium hydroxide ratio was reserved as 2.0, the alkaline activator-to-binder content ratio was kept as 0.4, the concentration of sodium hydroxide was kept as 14 M, superplasticizer was used to increase the fluidity of geopolymer concrete, and the source material used was 500 kg/m³, in control mix RHCM. The various percentages of basalt fibre used were 1, 5, 10, 15, 20 and 25% in mixes RHB1, RHB5, RHB10, RHB15, RHB20 and RHB25 and the results of blends with basalt fibre were compared with the control mix RHCM. The results publicized that RHB10 achieved higher 7, 28 and 90 day compressive strength of 43.0, 60.1 and 60.4 MPa, respectively. The mixes RHB1, RHB5 and RHB15 also gained compressive strength higher than control mix RHCM, but the mixes RHB20 and RHB25 showed a decrease in 7, 28 and 90 days compressive strength than control mix RHCM.