Strength and micro-structural performance of geopolymer concrete using highly burned rice husk ash

Abstract

Globally, many researchers use rice husk ash as a supplementary material in cement and geopolymer concrete. pozzolanic admixture. However, silica is insufficient for effective pozzolanic reaction in cement concrete and geopolymerization in geopolymer concrete. Therefore, choosing silica in the amorphous form is the primary objective, particularly agro-based as a precursor. Therefore, this experimental study was to synthesize geopolymer from rice husk ash (RHA) collected from a brick kiln and fly ash to utilize both materials effectively. In this study, the material characterization of both precursors was studied, and it was observed that RHA has desirable qualities as a precursor along with fly ash. The effects of adding RHA (0–20 by weight in percentage) to fly ash geopolymer concrete were examined. The partial inclusion of RHA content increased the compressive strength of the fly ash geopolymers. The very persistent and amorphous silica phase in the geopolymer concrete was primarily responsible for the enhancement of the geopolymer matrix. Because it was dissolved in the alkaline-activated solution, the amorphous silica significantly aided in the geopolymerization process. Although fly ash particles were still present in the geopolymer matrix, the unreacted fly ash particles did not add strength. However, performance would be better if the RHA content were more than 15% in the geopolymer concrete. The results presented in the study highlight the significant benefits of highly burned rice husk ash: it enhances geopolymerization and strength. Therefore, such in-depth investigation is imperative to judge the applicability of an appropriate form of RHA to attain higher strength and micro-structural performance.