%0 Journal Article
%A CHEN Xia
%A YANG Hua-quan
%A ZHANG Jian-feng
%T Influence of Phosphate and Fluoride on Cement Setting and ItsWorking Mechanism
%D 2015
%R 10.11988/ckyyb.20150049
%J Journal of Yangtze River Scientific Research Institute
%P 109-113
%V 32
%N 12
%X <p>Soluble and insoluble phosphate and fluoride were incorporated into cement respectively,and setting and hydration of pastes were investigated by using XRD and micro calorimeter.The results indicate that,when equivalent content of P<sub>2</sub>O<sub>5</sub> or F varies from 0.5% to 1.5%,setting time of cement is significantly increased by blended soluble phosphates such as Na<sub>2</sub>HPO<sub>4</sub> and Na<sub>3</sub>PO<sub>4 </sub>and insoluble CaF<sub>2</sub>,whereas insoluble phosphates such as CaHPO<sub>4</sub> and Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub> and soluble NaF have not obvious retarding effect on cement setting, even flash setting is seldom observed.Microscopic analysis on soluble phosphate and insoluble fluoride discloses that they retard cement setting due to lengthened induction period.As for soluble Na<sub>2</sub>HPO<sub>4</sub> and Na<sub>3</sub>PO<sub>4</sub>,they can decrease PH value,produce hydration products of aluminum phase and yield silicate solid solution,whereas insoluble CaF<sub>2</sub> retards hydration of cement by absorption effect of hydrogen bond,which comes from the combination of CaF<sub>2 </sub>with H<sup>+</sup> of hydration products located on surface of cement particles.</p>
%U http://ckyyb.crsri.cn/EN/10.11988/ckyyb.20150049