摘要
研究了α半水脱硫石膏流动度经时性及其影响因素,对掺减水剂石膏流动度经时性与流动度经时损失的内在原因进行了分析。α半水脱硫石膏流动度经时损失大,水化6 min流动度损失20%以上,α半水脱硫石膏快速水化对游离水消耗与束缚,以及双电层结构破坏,ξ电位迅速降低是导致流动度经时损失的内在原因。萘系减水剂(FDN)的分散作用主要依赖ξ电位的静电斥力,其分散稳定性差,流动度经时损失大;聚羧酸减水剂(PC)主要依靠空间位阻发挥分散作用,其分散稳定性较好,流动度经时性损失较小。高效减水剂应具备空间位阻效应,复配缓凝剂是抑制α半水脱硫石膏流动度经时损失的有效方法。
The time dependency of fluidity of α-hemihydrate desulfurization gypsum plaster and its influencing factors were investigated.After adding water reducing agents,its fluidity loss with time and the internal causes were systemically analyzed.The fluidity loss of α-hemihydrate desulfurization gypsum plaster is rapid,and the fluidity of its fresh palster would decrease over 20% after hydration for 6 min.The consumption and boundage of free water in the fresh plaster by the rapid hydration of α-hemihydrate desulfurization gypsum,the destruction of the double electronic layer structure which causes the fast reduction of Zeta potential are the internal cause of the fluidity loss.The dispersion of naphthalene-based water reducer mainly depends on electrostatic repulsive force caused by Zeta potential,so its dispersion stability is weak,and the fluidity loss is rapid.Polycarboxylic acid typed water reducer plays the role of dispersion though steric hindrance effect,so its dispersion is stabe,and its fluidity retaining is good.High performance water reducer for gypsum should have large steric hindrance.Combination with retarder can decrease the early hydration rate of gypsum plaster efficiently,and inhibit its fluidity loss with time.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2012年第2期396-400,共5页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金资助项目(No.50872160)
关键词
α半水脱硫石膏
流动度经时性
减水剂
吸附
α-hemihydrate desulfurization gypsum
time dependency of fluidity
water reducer
adsorption
