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通过测量水泥浆体的zeta电位,研究了碱金属硫酸盐对掺有萘系或聚羧酸减水剂的水泥浆体内自由溶液量的影响规律,以及碱金属硫酸盐和减水剂掺量对水泥浆体的保水能力和水泥颗粒之间作用力的影响,并讨论了浆体抗泌水能力变化的机理。结果表明:萘系减水剂和聚羧酸减水剂的加入都会降低浆体的自由溶液量,增加浆体保水能力;但在超过饱和掺量后,萘系减水剂会引起浆体内部吸附水量降低,对浆体产生不利影响,聚羧酸减水剂则没有类似作用。当水泥浆体中掺入碱金属硫酸盐时,聚羧酸减水剂受到的影响要显著小于萘系减水剂。在掺有减水剂的水泥浆体中,掺入适量的碱金属硫酸盐可以提高浆体的保水能力,降低泌水风险。萘系减水剂对应的碱金属硫酸盐最佳掺量约为2.7%SO3当量,聚羧酸减水剂则为2.5%SO3当量。碱金属硫酸盐通过快速溶出硫酸根离子,影响水泥颗粒表面电荷特性,进而影响浆体的抗泌水能力;溶解速率较慢的二水石膏没有类似作用。
By measuring the zeta potential of cement paste, the influence of alkali metal sulfate on the amount of free solution in the cement slurry mixed with naphthalene or polycarboxylate superplasticizer was studied, and the effects of alkali metal sulfate and water reducer on The water retention capacity of cement paste and the force between cement particles, and discussed the mechanism of the change of anti-bleeding capacity of slurry. The results show that the addition of naphthalene superplasticizer and polycarboxylate superplasticizer will reduce the amount of free solution in the slurry and increase the water retention capacity of the slurry. However, after exceeding the saturated content, the naphthalene superplasticizer will cause the internal of the slurry Decreased adsorption of water has an adverse effect on the slurry, polycarboxylate water-reducing agent has no similar effect. When the cement paste incorporation of alkali metal sulfate, polycarboxylate superplasticizer affected significantly less than naphthalene superplasticizer. In the cement slurry with water-reducing agent, adding appropriate amount of alkali metal sulfate can improve the water retention capacity of the slurry, reduce the risk of bleeding. Naphthalene superplasticizer corresponding to the best content of alkali metal sulfate is about 2.7% SO3 equivalent, polycarboxylate superplasticizer is 2.5% SO3 equivalent. Alkali metal sulfate quickly dissolves sulfate ions, affecting the surface charge characteristics of cement particles, thereby affecting the anti-bleeding ability of the slurry; digestion gypsum with slower dissolution rate has no similar effect.