Influence of Rice Husk Ash and Nano Clay on the Performance of Sustainable Self-compacting Geopolymer Concrete

Abstract

The present research aims to investigate the performance of self-compacting geopolymer concrete (SCGC) with sustainable binder materials such as Rice Husk Ash (RHA) and Nano Clay (NC). The main precursors used were fly ash (FA) and ground granulated blast furnace slag (GGBFS), and RHA was substituted for FA in proportions ranging from 0 to 30% to enhance the performance of the geopolymer matrix. The selected RHA mixture was further modified by changing the amounts of NC to obtain the desired results. Fresh, mechanical, durability, and microstructural properties of developed mixtures were assessed. The results indicated M-3 (55% FA+ 30% GGBFS + 15% RHA) as an optimum ratio for RHA and the addition of 2% NC (NC-2) further improved the mechanical performance of SCGC. The results indicated that the use of RHA to enhance the performance of these materials was effective up to a certain replacement rate, after which it gradually decreased. The inclusion of NC enhanced the performance by contributing to pore refinement and creating a more compact matrix. The chosen NC composition exhibited enhanced mechanical strength, reduced water absorption, reduced chloride ion ingress and sulfate exposure, and improved internal quality. SEM observations showed a rather dense and firmly bound geopolymer matrix. The selected NC-2 mix had a 28-day compressive strength of 50.92 MPa and water absorption of 3.20%. The chloride ion penetration and the sulfate strength deterioration at 90 days were 720 C and 5.84%, respectively. The findings demonstrate the potential of combining RHA and NC to produce sustainable and durable SCGC.