Effect of Adding Monohydrocalcite on the Microstructural Change in Cement Hydration

[Image: see text] This study explored the application of mineral carbonation products in the form of monohydrocalcite (MHC) as a Portland cement additive. This work studied the effect of adding monohydrocalcite on the microstructural change in cement hydration. We investigated the hydration and microstructure development of MHC–cement at different aging times and different MHC mass % values. Chemical composition changes over time were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The hydration behaviors of MHC blended with cement were monitored using thermogravimetric analysis and differential thermal analysis (TGA–DTA). The results indicated that the role of MHC in the hydrated cement was enhancing the cement hydration process with may increase the long term strength gain. We also discovered the effect of MHC in term of the long-term chemical reaction and forming the new phase formation of tilleyite in the hydrated MHC cement at long curing ages that was not present in the ordinary Portland cement (OPC) system.