Effects of calcined halloysite nano-clay on the mechanical properties and microstructure of low-clinker cement mortar

This paper explores the effects of calcined halloysite nano-clay (CHNC) on the physico-mechanical properties and microstructure of high volume slag (HVS) cement mortar. The principal objective of this research is to constitute a low-clinker cement mortar with high mechanical properties. Ordinary Portland cement clinker blended with 70% of ground granulated blast furnace slag (GBFS) was partially substituted with CHNC in ratios of 0%, 1%, 2%, 3%, 4%, 5% and 6% by weight. The results showed that the early age and long-term mechanical strengths of the slag cement mortars were significantly improved by the presence of CHNC. The slag cement containing 5 mass % of CHNC possessed the highest improvement of the mechanical properties and microstructure of hardened cement pastes and mortars. It was suggested that the higher pozzolanic activity of CHNC particles and the nucleation of calcium hydrosilicate (C-S-H) caused the enhanced strength development. (C) 2018 Published by Elsevier Ltd.