摘   要：研究了可溶性碱（K₂CO₃）对掺聚醚型聚羧酸减水剂（PC-1）和聚酯型聚羧酸减水剂（PC-2）的水泥水化热、凝结时间的影响，并对水化产物进行了X-射线衍射分析。结果表明，在掺PC-1或PC-2的水泥中，适当增加可溶性碱含量能降低水化放热速率以及放热量，能明显缩短单硫型水化硫铝酸钙（AFm相）的形成时间，加快水泥的水化进程。当PC-1掺量较低时，少量的可溶性碱对浆体有缓凝效应，过量（大于0.12%）则表现为促凝效应。当PC-1掺量较高（大于0.30%）时，可溶性碱对浆体表现出促凝效应；而对掺PC-2的浆体而言，增加可溶性碱含量能很大程度缩短浆体凝结时间。掺PC-1能使Ca(OH)₂（CH相）含量明显增多，可溶性碱则能进一步促进C₃S和C₂S的深度水化；而在掺PC-2的水泥中，增加可溶性碱含量则会减缓水泥后期水化。

Abstract: The influence of soluble alkali on hydration heat and setting time of the cement mixing the polyether type polycarboxylate-based superplasticizer (PC-1) and the polyester type polycarboxylate-based  superplasticizer (PC-2) have been investigated, and the hydration products are examined with X-ray diffraction analysis. The results show that appropriate increase soluble alkali can reduce the hydration exothermic rate and heat, shorten the formation time of AFm phase, and accelerate the hydration process of cement. When PC-1 dosage is low, a spot of soluble alkali have retarding effect on paste, but overdose resulted in accelerating its setting. When PC-1 dosage is high, soluble alkali can accelerate setting of paste, but for the paste mixed with PC-2, increasing soluble alkali content can shorten the paste setting time greatly. CH phase content increased significantly when the cement mixed with PC-1, and soluble alkali can further promote the depth hydration of C₃S and C₂S. However, when the cement mixed with PC-2, increasing soluble alkali content can slow down the late hydration of cement.