Early-Age Strength of Alkali-Activated Municipal Slag–Fly Ash–Based Geopolymer Mortar

Abstract

Inclusion of alkali-activated municipal slag cement–fly ash as a cement substitute can have an important outcome on the fresh mixtures and early-age strength of geopolymer mortar cured in different conditions. This study evaluates the effects of various quantities of activator on the workability and early-age strength of alkali-activated municipal slag–fly ash–based geopolymer mortar. Early-age compressive strength is measured under different curing conditions: steam curing, water curing, and air curing. In addition, early-age splitting tensile strength, flexural strength, and microstructure analysis using scanning electron microscopy (SEM) are examined for steam-cured mortar. Test results show that both curing regime and activator content in the main binder are significant factors influencing the performance evaluation of fresh mixtures and early-age strength of geopolymer mortar. A standard design equation is used to predict the compressive strength, and predications of splitting tensile and flexural strength of geopolymer mortar are calculated using another standard.