A novel low carbon cuing strategy for developing ultra-low water/binder cementitious materials (ULWC)

In this study, a novel microwave-CO2 combined curing strategy is proposed and its effect on the hydration kinetics and microstructure development of ultra-low water/binder cementitious materials (ULWC) is evaluated. To be specific, microwave pre-curing is firstly applied to ULWC in its early stage to promote the formation of Ca(OH)2, thereby activating carbonation. Subsequently, rapid CO2 curing technology is used to further optimize the microstructure of ULWC. Based on this, a detailed evaluation of the macro and micro properties of the newly developed ULWC is conducted. Experimental results show that microwave pre-curing can effectively increase the rate and extent of subsequent carbonation reactions, benefiting ULWC by forming a dense outer layer that enhances durability. Additionally, compared with standard curing the proposed combined curing strategy synergistically promotes the hydration and carbonation reactions of ULWC, increasing the early compressive strength from 56.44 MPa to 79.06 MPa while reducing the CO2 emission by 5994g. The practice demonstrates that the proposed combined curing strategy contributes to the production of advanced construction products with high mechanical performance and a low carbon footprint.