无碱液体水泥速凝剂的性能及其促凝机理  

Performance and action mechanism of alkali-free liquid accelerating agent

作　　者：刘梅艳 何真[1] 蔡新华[1] 陈晓润 

机构地区：[1]武汉大学水利水电学院,湖北武汉430072

出　　处：《新型建筑材料》2012年第6期36-40,共5页New Building Materials

基　　金：国家自然科学基金(50972109);国家重点基础研究发展计划项目(2009CB623201)

摘　　要：采用宏微观试验方法,研究无碱液态水泥速凝剂对水泥基材料的性能影响及其水化机理。结果表明:无碱液体速凝剂对水泥水化作用主要体现在1 d之内,水泥水化28 d时几乎不起作用;掺加6%速凝剂1 h水泥净浆硬化体有较多棒状AFt晶体形成,这些AFt晶体互相交错,填充在水泥浆体的孔隙中,使水泥净浆结构比基准水泥净浆结构更致密,使得其早期强度更高;无碱液体速凝剂的促凝机理主要是促进早期水泥浆体中AFt晶体的形成而达到促凝;SEM照片显示,生成的AFt是通过液相化学反应-沉淀析出途径生成,AFt晶体呈短柱状、随机取向,无序分布于整个硬化体空间,与基准水泥浆体形成的AFt途径完全不同,这可能是导致水泥浆体快速凝结及强度提高的主要原因。A so-called macro and micro testing method is employed to study on the impact of alkali-free liquid accelerating agent on the performance of cement-based composites,and analyze its hydration mechanism. The results show that the impact of accelerating agent on cement hydration mainly happens in 1 day,however, it has little affect on cement hydration within 28 days. When accelerating agent adding is 6%, there are much more stick ettringite in the structure of cement paste hydrated I hour, those generated ettringite,interleaved filled in the pore of cement paste,makes the structure of cement paste more compact and high early strength. Action mechanism of alkali-free liquid accelerating agent is to form more ettringite to make cement setting. SEM pictures show that ettringite is produced by liquid chemical reaction-precipitation exhalation,those short column random oriented ettringite disordered distribute throughout the whole cement paste,which is the main reason why setting time had been shorten and the compressive had been increased.

关 键 词：无碱液态速凝剂 水泥水化产物 微观结构 促凝机理 

分 类 号：TQ172.46[化学工程—水泥工业]