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。%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 appropri-ate 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.
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