Use of clays in alkaline hybrid cement preparation. The role of bentonites

'Portland-alkaline' hybrid cements (HYC), the latest generation of alkaline cements, are multi-component systems consisting in blends with high mineral addition and low portland cement contents. In the presence of alkaline activators, these systems set and harden into materials with excellent cementitious properties. This study explored the 2 and 28 day mechanical strength of a series of hybrid cements comprising blends with different proportions of portland cement (OPC) and dehydroxylated bentonite (BT). The reaction products were characterised with XRD and BSEM/EDX. The presence of an alkaline salt activator hastened reaction product precipitation and favoured strength development.