聚羧酸减水剂对混凝土结构影响

Influence of Polycarboxylate Superplasticizer on Concrete Structure

混凝土结构决定其性能。通过扫描电镜和压汞试验,表征和分析了聚羧酸减水剂对混凝土硬化水泥浆体、界面结构和水泥石孔结构的影响。结果表明,早龄期的混凝土硬化水泥浆体和界面结构裂纹较宽,裂缝较多,而龄期长则结构较密实;相同龄期掺有聚羧酸减水剂的混凝土硬化水泥浆体和界面过渡区结构裂缝数量、裂纹宽度均小于萘系减水剂;聚羧酸减水剂降低了水泥石的平均孔径,最可几孔径和孔隙率;少害孔和无害孔的含量多,而有害孔和多害孔含量少。聚羧酸减水剂对混凝土结构的作用优于萘系减水剂。

The performance of concrete was mainly determined by its interface structure.The effects of polycarboxylate superplasticizer on hardened cement paste structure,interface structure and pore structure of concrete were analyzed by scanning electron microscopy and mercury test.The results showed that the early age hardened cement paste structure and interface structures of concrete have wider and more cracks,and accordingly become more dense to longer age hardened cement paste and interface structure of concrete.When cured for the same age,cement paste and interface structure of concrete added with polycarboxylate superplasticizer show clearly narrower and less cracks than those added with naphthalene superplasticizer.Polycarboxylate superplasticizer greatly reduces the average pore size,most probable pore diameter and porosity,and accordingly,the cement has higher content of less harmful and harmless hole,and lower probability of forming harmful hole.It can be concluded that polycarboxylate superplasticizer is much superior to naphthalene superplasticizer.