混凝土外加剂对硫铝酸盐水泥水化历程的影响.pdfVIP

学兔兔 2011年第1期 混凝 土 与水 泥 制 品 2011 Nol 1月 CHINA C0NCRE I AND CEMENT PR0DUCTS January 混凝土外加剂对硫铝酸盐水泥水化历程的影响 黄士元 ，邬长森 ，杨荣俊 (1．同济大学，上海 200092；2．北京市政路桥建材集团有限公司，100176) 摘 要：采用X射线半定量分析方法研究了在快硬混凝土中掺加缓凝剂和促硬剂对硫铝酸盐水泥凝结时间、 水化历程、水化产物种类的影响。结果表明：快硬硫铝酸盐水泥的水化产物主要有AFt、AFm、CAH ，及A1(oH)，，而 C S的水化非常缓慢；快硬硫铝酸盐水泥快凝早强的主要原因是AFt的生成，而后期强度发展停滞甚至倒缩的原因 主要是 AFt向AFm的转化，后期 C2S的水化可能弥补这一缺陷；缓凝剂的作用是阻碍了c 3s和铁铝矿物的水化， 并且抑制了AFt向AFm的转化；促硬剂的作用是与缓凝剂发生化学反应，终止了缓凝作用，使硫铝酸盐型水泥矿物 恢复正常水化。 关键词：快硬硫铝酸盐水泥；缓凝剂；促硬剂；水化历程；水化产物 Abstract： I、he effects of retarder and accelerator on the setting time．hydration progress and hydration products of rapid hardening SUlphoaluminate cement are studied by semi-quantitative XRD analysis method．The results show that the main hydration products of rapid hardening su1ph0aluminate cement are Aft，AFm，C．AHl3 and A1(OH)3，the hydration of C2S proceeds rather slowly．The rapid setting and strength development are due to the formation of AFt．whereas the cease of strength increase and even strength regress of sulphoaluminate cement at later ages are caused by conversion of AFt to AFm．the hydration of C2S at later ages may supply this gap．The effect of retarder may be explained as that it prevents the hydration of C4A3 S and fer ric aluminium compounds and restrains the conversion of AFt to AFm．The added accelerator takes a chemical reaction with the retarder and immediately stops its retarding action，SO that the accelerator makes C 1S recover to hydrate normally． Key words：Rapid hardening sulph0aluminate cement；Retarder；Accelerator；Hydration process；Hydration products 中图分类号：TU528．042 文献标识码：A 文章编号：1O00—4637(2011)01—07—06 O 前言 种和根据施工条件(温度、运距)确定掺量，以控制 硫铝