水泥石灰固化软土中的钙矾石形成研究

Ettringite formation in lime and cement-stabilized clay

使用水泥或石灰来改良软土工程特性的技术很早以前就已经提出并得到广泛使用,然而针对水泥或石灰固化软土的研究结果显示由于钙矾石等高膨胀性矿物的生成可能会使得固化土发生了严重的膨胀破坏。通过X射线衍射试验(XRD)和扫描电子显微镜检查法(SEM)可以鉴定固化材料中是否有针状结晶的钙矾石存在。本文对钙矾石对水泥或石灰固化土性质的影响及原因的研究进行了回顾,同时对各因素包括pH、含水率、温度、黏粒含量和硫酸盐化水平对钙矾石生成的影响进行了总结。结果表明钙矾石的生成对水泥或石灰固化土的影响有利有弊,且钙矾石的生成是一种复杂的现象,受到多因素的影响。

Improving the behaviour of soft clays using lime or cement is not new. The studies report the high swelling failures in lime and cement-stabilized clays due to the formation of swelling minerals such as ettringite. The formation of needle-shaped ettringite in the stabilized materials can be identified using the X-ray diffraction(XRD) and the scanning electron microscopy(SEM). The earlier studies on the influence of ettringite upon the lime and cement-stabilized clays are reviewed and the factors influencing ettringite formation are examined. The results indicate that the formation of ettringite has both pros and cons in lime and cement-stabilized clays, and it is a complex phenomenon influenced by several factors.