Performance of Slag‑Pumice‑Based Alkali‑Activated Mortar at Ambient Environment

Abstract

Sustainability in construction materials is a hot topic of research, and alkali-activated materials are believed to be a real alternative to OPC concrete. The manufacturing process of cement emits nearly 8% of CO2 into the atmosphere. This study utilised slag as a base binder in the alkali-activated mortar (AAM). The pumice powder was used as a replacement ratio of (0, 10, and 20) % by the mass of the slag. Three various ratios of alkali solution-to-binder ratio (s/b) were utilised (0.4, 0.5, and 0.6) for a detailed evaluation of the fresh and hardened properties of alkali-activated mortar. The setting time and flow test were conducted, and the mechanical characteristics were investigated through compressive strength, flexural strength, and direct tensile strength. Furthermore, fire resistance, water absorption, water sorptivity, porosity, density, efflorescence, and sulphate resistance were all examined to evaluate the durability characteristics of AAM. Results showed that increasing the amount of pumice powder in the mixture reduced its flowability for all s/b ratios. At a s/b of 0.4, increasing the pumice powder concentration degraded the mechanical and durability qualities. Simultaneously, increasing the amount of pumice powder at both s/b of 0.5 and 0.6 increased the mechanical and durability properties.