pH对含长支链聚羧酸减水剂水泥浆体性能的影响

Influences of pH on properties of cement paste containing polycarboxylate superplasticizers with long side chain

探讨了pH对含长支链PCE(聚羧酸减水剂)水泥净浆流动度和减水率的影响,并对该水泥试块的压缩强度和凝结时间进行了研究。结果表明:pH对含长支链PCE水泥净浆流动度和减水率的影响较小;随着龄期的延长,pH对水泥试块的压缩强度由积极影响变为消极影响;随着pH的不断增加,水泥的初疑时间和终凝时间均呈先长后短态势,并且均在pH为9时相对最长,不同配浆水的pH均会使含长支链PCE水泥浆体出现缓凝现象;当配浆水的pH为13时,含长支链PCE水泥试块的微观结构相对较差,不利于增强水泥试块的压缩强度。

The influences of pH on fluidity and water- reducing ratio of cement paste containing PCE （polycarboxylate superplasticizer） with long side chain were discussed, and the compressive strength and setting time of cement samples were investigated. The results showed that the influences of pH on fluidity and water-reducing ratio of cement paste containing PCE with long side chain were less. The influences of pH on compressive strength of cement samples had a trend of positive-negative with increasing age. The setting time （such as initial setting time and final setting time） of cement samples had a trend of long-short with increasing pH, and the setting time was relatively longest at pH=9, the mixing water with different pH could all retard coagulation of cement paste containing PCE with long side chain. The cement paste containing PCE with long side chain could not enhance compressive strength of cement samples because its microstructure was relatively poor when pH of mixing water was 13.