聚羧酸分子结构对混凝土早强性能的影响

设计不同的侧链长度、酸醚比和分子量制备了系列聚羧酸减水剂样品,采用GPC方法测试了系列样品的分子量和聚醚转化率.通过砂浆和混凝土性能评价试验表征了聚合物的分散性能和力学性能,用微量热仪监测了水泥水化18h内的水化放热趋势.结果 表明,聚羧酸分子中聚醚侧链长度、酸醚比和分子量均能明显影响砂浆的早期强度,分子结构综合影响早...

Effect of Molecular Structure of Polycarboxylate Superplasticizers on Early Age Strength of Concrete

A series of polycarboxylate superplasticizers were prepared by designing different side chain lengths,acid-ether ratios and molecular weights.The molecular weight and polyether conversion of the samples were investigated by GPC method.The performance of dispersion and mechanical properties of the polymers were characterized by the mortar and concrete performance test.The trend of hydration heat release within 18 h of cement hydration was monitored by microcalorimeter.The experimental results show that the length of polyether side chain,acid-ether ratio and molecular weight in polycarboxylate superplasticizers can significantly affect the early age strength of mortar.The effects of early age strength are caused by multiple factors of molecular structure.The hydration exothermic process proves that the optimized molecular structure can accelerate the hydration of cement.The influence rules for hydration heat are consistent with the results of mortar strength test.The results of concrete performance test show that the series of samples can shorten the setting time of concrete,increase the early age strength,and be particularly important not to affect the development of later strength.