Unlocking the potential of ordinary Portland cement with hydration control additive enabling low-carbon building materials
Xuerun Li, Harald Grassl, Christoph Hesse, Joachim Dengler
Abstract
Abstract Ordinary Portland cement (OPC) is the core ingredient of many construction materials. In 2022, 4.1 billion tons were used worldwide, contributing to ~8% of CO 2 emissions ( ~ 3 Gt/year). Nevertheless, the complete strength-generating capacity of OPC remains unrealized due to the restricted conversion of aluminates to ettringite, caused by conventional hydration kinetics. Here we show a hydration control additive that selectively modifies the hydration kinetics, thereby facilitating enhanced dissolution of aluminates (calcium aluminoferrite and tricalcium aluminate) in OPC, which promotes ettringite formation at a desired time. Increasing ettringite content improves packing of the hardened cement, resulting in ~50% higher specific strength and enabling cement reduction. It also increases OPC strength development efficiency, reducing carbon footprint by ~30%. The use of this additive can be combined with methods such as reducing water and/or using supplementary cementitious materials (SCMs) to prepare building materials with significantly fewer CO 2 emissions than those from conventional OPC.