A Potential Pozzolanic Material consisting of Rice Straw Ash and Fly Ash for Geopolymer Mortar Production-based Cementitious System

Rice straw waste, among other issues, is a significant source of air pollution and methane emissions from biological decomposition. This study examines the use of Rice Straw Ash (RSA), when combined with Fly Ash (FA) and Laterite Soil (LS), as a pozzolan in cementitious systems. The study's purpose is to examine the microstructure and compressive strength of a geopolymer mortar composed of FA, RSA, and LS. The RSA is activated with sodium hydroxide (NaOH), an alkaline activator, with concentrations of 6, 12, and 15 M NaOH. After air and water curing for 3, 7, and 28 days, the compression strength of the geopolymer mortar was tested. To determine the dominant compound of the pozzolan reactions that were generated in cementitious systems, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were employed. When geopolymer mortar is cured in air and water, its compressive strength increases with age. This is due to the fact that RSA, FA, and LS have the ability to form iron oxide (Fe3O4) in the amorphous phase and have a strong bond with alumina (Al2O3) and silica (SiO2). The material's fineness affects its compressive strength as well. This study intends to replace cement in mortar and concrete utilizing environmentally friendly materials. Furthermore, the creation of geopolymer material usually requires the use of oven heat to enhance the geopolymerization procedure. However, this study shows that this method does not require oven heat.