Valorization of waste perlite powder in geopolymer composites

Abstract

The utilization of industrial waste by-products including blast furnace slag (BFS) for geopolymer (GP) production gained considerable attention in recent years. Yet, the development, characterization, and optimization of this kind of material in the presence of waste perlite powder (WPP) has not been investigated. This study assesses the effect of binder content, WPP replacement rate, alkaline activator-to-binder ratio (s/b), and sodium silicate-to-sodium hydroxide ratio (S/H) on the fresh, mechanical, and durability performance of GP mortars blended with BFS and WPP precursors. The optimum proportions determined using the multicriteria Taguchi method were found to contain 600 kg/m3 binder content, 25 % WPP replacement rate, 0.60 s/b, and 2.0 S/H. The reaction kinetics and morphology of precipitated compounds, including the scanning electron microscopy and energy dispersive X-ray analysis, highlighted the rate of activating the calcium aluminosilicate gels and dense microstructure of the optimum mixture. Such data can be of particular interest to researchers and engineers seeking to valorize the use of industrial wastes in GP applications.