banahCEM – comparison of properties of a laterite-based geopolymer with conventional concrete

This paper presents the overview of a project, as well as selected results from the experimental work aimed at direct comparison of the physical and durability properties of room temperature cured geopolymer and Portland cement concretes (GPCs and PCCs, respectively). Geopolymer binder was formed by reacting low purity geologically-originated lateritic clay, banahCEM(a), with an alkali silicate activator, banahCEM(b). Economical and “industry friendly” mix design of GPCs was developed to satisfy common medium and high strength applications. In order to allow a like-for-like comparison, both GPCs and PCCs were proportioned with equivalent paste volume and characteristic compressive strength. It was found that in the first 24 hours after mixing the GPCs achieved 55–75% of their 28-day strength, while equivalent PCCs gained 37–43%. Selected durability properties of developed geopolymer mortars, such as acid (solutions of H2SO4 and HCl) and sulfate (solutions of Na2SO4 and MgSO4) resistance have been found to be better than those of Portland cement systems. Room temperature curing and reported engineering properties make this geopolymer binder most suitable for harsh environment applications, where rapid strength gain is of essence, e.g. repair applications, pre-cast industry (fast mould turnover), tunnel or mine linings.