Understanding the potential role of precursor content in the geopolymer concrete strength development

Abstract

A common pozzolanic admixture used by several studies is agricultural waste ashes. An amorphousaluminosilicate substance is knownas pozzolanic admixture, which may not be inherently cementitious but combines with water and calcium hydroxide to produce cementitious substances.As precursors, fly ash and ground-granulated blast furnace slag (GGBS), industrial by-products, have been employed as raw materials in geopolymer concrete. However, a significant prerequisite for the development of geopolymer concrete, aluminosilicate sources are abundant in agricultural waste ashes as well. Therefore, this experimental work aimed to create a geopolymer using industrial waste products and agricultural waste ashes to effectively use readily available and inexpensive agricultural waste materials like rice husk ash (RHA) and bagasse ash (BA). In this study, various geopolymer concrete mixtures with variable levels of precursors (fly ash, GGBS, RHA, and BA) were cast and tested for their 28-day compressive strength and X-ray diffraction (XRD) analysis. Based on the findings of the compressive strength experiments, it is found that addition of RHA and BA significantly improves the compressive strength of the geopolymer concrete. XRD traces of geopolymer concrete blended with RHA and BA revealed that both RHA and BA added geopolymer concrete has denser intermolecular bonding of materials as compared to the fly ash based and GGBS based geopolymer concrete. Additionally, the geopolymer concrete that incorporates RHA has a higher cost-effectiveness than geopolymer concrete that is combined solely with industrial by-products.