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利用等温吸附、XRD、DTA和化学分析研究了硫酸盐相容型聚羧酸减水剂(PCA)与水泥颗粒之间的相互作用机理。结果表明,聚羧酸减水剂能加速水泥水化初期钙矾石(AFt)和单硫型水化硫铝酸钙(AFm)的形成,并且当水泥中存在石灰石微粉时,还可加速早期单碳型水化硫铝酸钙的形成,从而降低了水泥颗粒对PCA的吸附。由于建立了静电斥力与空间位阻作用协同作用机制,PCA在获得高分散性的同时,使混凝土具有优异的坍落度经时保持性能。硫酸盐相容型聚羧酸减水剂与萘系高效减水剂相容,可共同使用。
The mechanism of the interaction between sulfate-compatible polycarboxylate superplasticizer (PCA) and cement particles was studied by isothermal adsorption, XRD, DTA and chemical analysis. The results show that the polycarboxylate superplasticizer can accelerate the formation of early vitrification of AFt and monosulfide hydrated calcium sulphoaluminate (AFm), and accelerate the early phase of limestone micropowder The formation of single-carbon hydrated sulphoaluminate reduced the adsorption of PCA to cement particles. Due to the establishment of a synergistic mechanism of electrostatic repulsion and steric hindrance, PCA achieves high dispersibility and at the same time provides excellent retention of concrete properties over time. Sulfate-compatible polycarboxylate superplasticizer compatible with naphthalene superplasticizer can be used together.