Influence of Rice Husk Ash and Wood Bark Ash on Geopolymer Mortar Mechanical Properties at Varying Molarity Ratios

Air pollution, a major global challenge, is increased by cement manufacturing, which emits significant amounts of carbon dioxide and contributes to global warming. To support sustainable development, there is a pressing need to adopt eco-friendly al-ternatives. Agricultural waste burning, which generates methane, further exacerbates air pollution and poses risks to public health. As agricultural waste continues to rise due to growing food demand, researchers have explored utilizing agricultural waste ashes as substitutes for cement in both traditional and geopolymer concrete. These ashes, rich in silica and alumina, enhance pozzolanic reactions and improve concrete durability. Industrial byproducts like fly ash, along with agricultural byproducts such as rice husk ash (RHA) and wood ash (WA) are increasingly used in replacing Portland cement, leading to the development of environmentally sustainable geo-polymer concrete. This study aims to optimize geopolymer mortar production by utilizing (RHA), wood bark ash (WBA), and fly ash (FA) in combination with sodium hydroxide (NaOH) as an alkaline activator at two molarities (12M and 14M). The study investigated the mechanical properties of geopolymer mortar with varying agricultural ash replacement percentages (5%, 10%, 15%, 20%, and 30%) for fly ash. The best results were observed at a 20% replacement level, with enhanced me-chanical properties at 14 molar than 12 molar.