Compressive Strength of Ambient- and Heat-Cured Fly Ash Geopolymer Concrete after High-Temperature Exposure

Abstract

This paper investigates the behavior of low-calcium fly ash geopolymer concrete subjected to high temperatures in both ambient-cured and heat-cured situations. The temperature at which concrete samples were gradually heated to 100, 200, 400, 600, 800, and 1000°C was maintained at 5°C per minute. The impact of elevated temperatures on geopolymer concrete was evaluated by the use of microstructural analysis, visual inspection, mass loss measurement, fracture evaluation, and residual strength determination. Interestingly, the cross-sectional and surface fractures peaked at 800°C and decreased around 1000°C. Based on the findings, all of the concrete samples remained strong after two hours at 600°C.