A study on hydration, compressive strength, and porosity of Portland-limestone cement mixes containing SCMs

In this study, the hydration of Portland-limestone cement (PLC) pastes and the relationship between compressive strength and porosity of PLC mortar samples containing various levels of supplementary cementitious materials were examined using XRD and MIP techniques. The results revealed that part of the limestone portion of Portland-limestone cements reacts with the alumina phases and produces carboaluminates, which increases compressive strength and reduces porosity. There is an optimum level of limestone corresponding to the available amount of alumina in the binder. Addition of slag or metakaolin provided more alumina, causing more limestone to participate in the hydration reaction and increasing the optimum level of limestone.