摘   要：以水泥净浆开裂时间和混凝土28d拉压比为标准，评价混凝土抗裂性能。分析了合成的聚羧酸减水剂中羧基、氨基、磺酸基、羟基、酯基等各官能团比例、聚醚支链长短、减水剂分子量大小等因素对混凝土抗裂性能的影响。实验结果表明：聚羧酸减水剂分子结构中羧基含量增加，羟酯基与羧基摩尔比为1：1.5时，聚羧酸减水剂对混凝土的抗裂性能较好；支链聚合度大，减水剂分子量大，混凝土抗裂性能提高；氨基、磺酸基对混凝土抗裂性影响较小。初步探讨了聚羧酸减水剂提高混凝土抗劈裂性能的机理。

Abstract: Based on  the ratio of tensile strength to compressive strength of concrete in 28 days and cement paste cracking time, the crack resistance of concrete is evaluated. The main factors influencing crack resistance of concrete, such as ratio of groups of caroxyl, amino, sulphonic, hydroxyl and ester, chains of polyether and molecular weight of synthesized polycarboxyl superplasticizer, are discussed by experiment. The results show that crack resistance of concrete is better when there are many caroxyl or mole ratio of hydroxy-ester to caroxyl is 1:1.5 in molecular structure of polycarboxyl superplasticizer; the crack resistance of concrete increases as level of chains of polyether and molecular weight of synthesized polycarboxyl superplasticizer grow larger; amino and sulphonic have little effects on it. The mechanism of polycarboxyl superplasticizer improving crack resistance of concrete is simply studied.