Effects of Na2CO3 on engineering properties of cement–limestone powder–slag ternary blends

Cement–limestone powder–slag ternary blends are construction materials that can significantly reduce carbon emissions and have a high potential for broad applications. This study investigated the effects of Na 2 CO 3 on the engineering properties, hydration, and hydration products of cement–limestone powder–slag ternary blends. The compressive strength , ultrasonic velocity, and surface resistivity of ternary cement blends were determined. The exothermic process of paste hydration was monitored for 7 d. Furthermore, the hydration products at different stages were characterized and analyzed by X-ray diffraction, thermal gravimetry analysis, and Fourier transform infrared spectroscopy . Results for the heat of hydration indicated that Na 2 CO 3 accelerated the early hydration of the ternary blends. Adding Na 2 CO 3 improved the 1 d compressive strength and surface resistivity of the cement paste . As the hydration progressed, Na 2 CO 3 limited the compressive strength and ultrasonic velocity development of the ternary cement blends in the later stages. With an increase in the content, Na 2 CO 3 reduced the calcium hydroxide inside the cement and increased the crystallinity of calcium carbonate . This study addresses the gap in existing literature regarding the use of Na 2 CO 3 in cement–limestone powder–slag ternary blends. Furthermore, it presents new ideas for producing cement materials with a low carbon footprint and high durability. • Na 2 CO 3 increases the surface resistivity of the cement-limestone powder-slag ternary blends. • The addition of Na 2 CO 3 improved the formation of carboaluminate at an early stage. • The engineering performance of Na 2 CO 3 doped ternary cement blends was tested in detail. • The effect of Na 2 CO 3 on the hydration of ternary blends was investigated.