考察了不同阳离子含量的长侧链两性聚羧酸系减水剂(APCs)对水泥早期水化的影响。结果表明,相较于纯阴离子型的普通聚羧酸系减水剂 PCs,含阳离子的APCs能够加速水泥的水化,促进早期水化产物生成,从而提高水泥早期强度。当共聚物中阳离子的含量为10％时(APC-10),水泥浆体最快进入水化加速反应阶段。热重与扫描电镜的结果也证实,在相同的龄期内,掺 APC-10的样品中生成更多的羟钙石和簇状水化产物。但随着阳离子含量的进一步增加,长侧链两性聚羧酸减水剂对水化的促进作用减弱甚至消失,试件的早期强度反而有所降低。
The influence of cation content in main chain of amphoteric polycarboxylate-based superplasticizers (APCs)on the early hydration of cement was investigated.The result indicates that,compared with the tradi-tional anion polycarboxylate,APCs with cation groups promotes the hydration of cement and the formation of hydration product,thereby increasing the early strength of cement paste.The calorimetry shows that cement with APC-10 (10% content of cationic groups)has an earlier acceleration period.Results from DSC and SEM confirm the trend that more hydration products,such as portlandite and clusters of C-S-H,are formed in sam-ple with APC-10.However,when cationic content was increased to 15% and 20%,the hydration promotion effect of long side chain APCs was reduced or even disappeared resulting in a slight decrease of the early strength of cement paste.
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