Use of waste dealuminated metakaolin in alkali-activated cement mixes

This paper explores the feasibility of using dealuminated metakaolin (DMK), a hazardous by-product of the alum industry, in alkali-activated cement (AAC) mixes, as an outlet for this voluminous hazardous waste, alternative to landfilling. After reviewing global DMK waste manage-ment practices and emerging uses as a pozzolanic materi-al, the study experimentally investigates geopolymer mortars made with 75% Ground Granulated Blastfurnace Slag (GGBS) and 25% DMK. Activated with various alkaline solutions across different silicate modulus val-ues (Ms 0.2–1.2), the mortars were tested for compressive strength (CS). Some mixes achieved compressive strengths over 40 MPa after just 7 days of curing, demon-strating the potential of DMK in structural concrete ap-plications. Ongoing research aims to elucidate the inter-action between DMK and GGBS, towards further optimi-zation of the AAC systems to enhance mechanical per-formance, durability, workability, and setting behaviour.