硅酸盐学报2016，Vol.44Issue(5)：647-650,4.DOI:10.14062/j.issn.0454-5648.2016.05.04
预水化对水泥性能及水泥-聚羧酸系减水剂相互作用的影响
Effect of Prehydration on Properties of Cement and Interaction Between Prehydrated Cement and Polycarboxylate Superplasticizer
摘要
Abstract
Fresh Portland cement was exposed to the specific conditions of (20±2) ℃ and 85%–90% relative humidity. Effect of prehydration on the water requirement of normal consistency of cement, the cement hydration behavior and the development of mortar strength at different exposure time was investigated. The interaction between prehydrated cement and polycarboxylate superplasticizer (PCE) was also assessed. The results show that the prehydration rate decreases with increasing the exposure time. However, the water requirement of normal consistency decreases firstly and then increases rapidly as the growth of exposure time due to prehydration. Meanwhile, prehydrated cement for 4 d exposure has the smallest water requirement of normal consistency. The prehydrated cements exhibit a lower value of highest hydration temperature and a lower exothermic rate than fresh cement. The exothermic rate of cement increases with increasing the exposure time when the exposure time is less than 10 d. The cement for 10 d exposure even has a greater exothermic rate rather than fresh cement sample. This phenomenon can lead to an abnormal setting behavior of prehydrated cement. In addition, prehydration can affect the strength development especially the flexural strength development of mortar. Prehydration also influences the effectiveness of PCE, the dispersion ability and dispersion retention ability of PCE increases firstly and then decreases as the increasing of exposure time. PCE in the paste of prehydrated cement exposed for 4 d exhibit the best dispersion and dispersion retention ability. Its initial fluidity is 136% of that for fresh cement paste, and its fluidity still remains at 235 mm after 120 min. However, PCE lost its dispersion ability to cement exposed for 20 d and 30 d.关键词
预水化/陈化/水泥水化/水泥胶砂强度/聚羧酸系减水剂Key words
prehydration/aging/cement hydration/strength of cement mortar/polycarboxylate superplasticizer分类
建筑与水利引用本文复制引用
孙振平,水亮亮,杨海静,刘毅,冀言亮..预水化对水泥性能及水泥-聚羧酸系减水剂相互作用的影响[J].硅酸盐学报,2016,44(5):647-650,4.基金项目
国家高铁联合基金(U1536207)；国家自然科学基金(51178339)。 （U1536207）
