General properties of blast furnace slag-based geopolymer concretes produced with expanded perlite aggregate

In this study, the general properties of geopolymer concrete incorporating ground granulated blast furnace slag (GGBFS) as the primary binder and varying proportions of expanded perlite aggregate (EPA) as a partial replacement for fine and coarse aggregates were systematically investigated. A total of six different mix designs were prepared by substituting conventional aggregates with EPA at volumetric replacement levels of 0%, 10%, 20%, 30%, 40%, and 50%, respectively. Following a 28-day curing period under ambient laboratory conditions, the hardened concrete specimens were subjected to a series of experimental evaluations, including compressive strength testing, ultrasonic pulse velocity (UPV) measurements, thermal conductivity analysis, and high-temperature exposure testing. The results obtained from the mixes were compared against those of the control mixture (G-0), which contained no EPA.For the assessment of high-temperature performance, selected specimens were exposed to thermal treatment at predetermined temperatures for one hour, after which their residual compressive strengths and weight losses were measured. The experimental findings indicated that increasing the EPA content led to a significant reduction in the mechanical and thermal performance of the geopolymer concretes. Specifically, higher EPA replacement ratios resulted in notable decreases in compressive strength, UPV values, and thermal conductivity coefficients. Furthermore, both the loss in compressive strength and the increase in weight loss after thermal exposure were positively correlated with the increase in EPA content. Keywords: Geopolymer concrete, Blast furnace slag, expanded perlite aggregate, high temperature