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为揭示磷酸盐与氟盐延缓水泥水化的作用机理,向硅酸盐水泥中分别掺入易溶性和难溶性的磷酸盐和氟盐,利用XRD、微量热仪等微观测试手段,研究了不同胶凝体系的凝结特性和水化特性。试验结果表明,P_2O_5与氟当量掺量在0.5%~1.5%范围内时,易溶性的Na_2HPO_4,Na_3PO_4与难溶性的CaF_2会显著延缓水泥的凝结时间,而难溶性的CaHPO_4,Ca_3(PO_4)_2与易溶性的Na F则不会产生明显的缓凝,甚至还会出现速凝。微观测试表明,易溶性的Na_2HPO_4,Na_3PO_4和难溶性的CaF_2是通过延长水泥的水化诱导期导致凝结时间延长。其中,Na_2HPO_4,Na_3PO_4主要通过降低液相pH值、形成铝相水化产物以及硅酸盐固溶体等多重效应叠加,CaF_2则是通过与水泥颗粒表面水化产物的H+形成氢键产生的吸附效应,延缓水泥的水化。
In order to reveal the mechanism of phosphate and fluoride salt retarding the hydration of cement, different soluble and insoluble phosphate and fluoride salts were incorporated into Portland cement respectively. The effects of different salts Condensation and Hydration Properties of Gelled Systems. The experimental results showed that the soluble Na2HPO_4, Na_3PO_4 and insoluble CaF_2 significantly slow down the setting time of P_2O_5 and F_ (PO_4) _2 With soluble NaF does not produce significant retardation, and even quick-setting. Micro-tests showed that the soluble Na_2HPO_4, Na_3PO_4 and insoluble CaF_2 prolong the setting time by prolonging the hydration induction period of cement. Among them, Na_2HPO_4 and Na_3PO_4 are mainly superposed by multiple effects such as decreasing the liquidus pH, forming aluminum hydrate and silicate solid solution, CaF_2 is the adsorption effect by hydrogen bond with H + of cement hydration product, Delay the hydration of cement.