硅酸盐学报

CaCO₃在硬化水泥浆体中不是惰性物质,其除了能与水泥中含铝相的水化产物进一步反应生成碳铝酸钙外,还对硅酸盐相的水化产物起作用。本文通过对掺加不同量CaCO₃的C_3S早期水化放热速率的测定,XRD分析以及SEM观察,探讨在CaCO₃存在时C_3S的早期水化及水化产物的变化。 结果表明,CaCO₃加速C_3S的早期水化,在一定范围内.其加速作用随掺入量增加而增强。在CaCO₃和C_3S浆体的界面区靠近CaCO₃表面一侧出现新的产物——碱式碳酸钙,这一新相的存在有利于界面区结构的改善、结合力增强,最终有利于硬化水泥浆体力学性能的提高。

CaCO₃ in hardened cement pastes is not an inert material.Besides reacting with hydrates of alumina-containing phases in cement to form calcium carboaluminate, it can also react with hydrates of silicate phases.In the present paper, through the measurement of the rate of heat evolution of C_3S hydration, XRD and SEM analysis, changes in the hydration of C_3S and its hydrates at the early period in the presence of CaCO₃ are discussed.The results show that CaCO₃ accelerates the hydration of C_3S in the early period. This tendency will be stronger with the increase of the amount of CaCO₃ in a certain range.Furthermore, in the interracial zone of CaCO₃ and C_3S, near the side of CaCO₃, a new hydrate, basic calcium carbonate, occurs and strengthens themicrostructure of the interracial zone and increases the binding force occurs,and the mechanical properties of hardened cement paste are thus improved.