Microstructural, mechanical, and durability assessment of sustainable geopolymers synthesized using rice husk ash, a byproduct of the rice industry
Atif Khan, Mohammad Jamal Khattak, Thomas C. Pesacreta, Lily Ann Hume
Abstract
Rice cultivation generates substantial quantities of rice husk, which, upon combustion, produces rice husk ash (RHA) – an abundant, silica-rich agricultural byproduct. While RHA presents environmental disposal challenges, its high amorphous silica content offers potential for sustainable material applications. This study investigates the incorporation of high-volume RHA into geopolymer bricks, aiming to develop eco-friendly construction materials. Utilizing response surface methodology, the mix parameters, including RHA content, alkali ratio, and curing conditions, were optimized. The results demonstrated that geopolymer bricks containing up to 40% RHA achieve compressive strengths meeting ASTM standards and exhibit enhanced acid resistance compared to traditional cement-based mixtures. Microstructural analyses confirm the formation of durable phases such as mullite and albite. This work highlights a viable pathway for valorizing agricultural waste into sustainable building materials, contributing to circular economy practices and carbon footprint reduction.