掺膨胀剂水泥-黏土浆体膨胀性能的试验研究

Experimental Study on the Expansion of Cement-clay Paste Mixed with Expansive Agents

针对传统水泥灌浆材料析水率较大、固相体积收缩,导致地基加固质量下降的问题,以黏土为掺合料,硫铝酸钙类膨胀剂为主要添加剂,采用正交试验研究改性水泥浆体的膨胀性能,探讨了水固比、黏土掺量、水玻璃掺量和膨胀剂掺量对浆体限制膨胀率的影响,得到了注浆浆体最佳配合比.研究结果表明:加入一定比例的黏土、水玻璃和膨胀剂可以提高水泥浆体的膨胀率.限制膨胀率随龄期先增大后减小.水固比对限制膨胀率的影响最大,其次是膨胀剂掺量.限制膨胀率随水固比的增大而减小,随膨胀剂掺量的增大而增大.水固比0.6、黏土掺量15%、水玻璃掺量2%和膨胀剂掺量为12%时为工程应用的参考配合比.

Traditional cement grouting materials have the problems of large water extraction rate and solid phase volume shrinkage,which lead to the decline of foundation reinforcement quality.Therefore,we used clay as admixture and calcium sulphoaluminate expansive agents as main additive,then an orthogonal test was conducted to study the expansion performance of modified cement paste.Next,the effects of water-solid ratio,clay content,water glass and expansion agent dosage on the limited expansive rate of the slurry were discussed,and the best mixing ratio of grouting was obtained.The results show that adding a certain proportion of clay,water glass and expansion agent can increase the expansion rate of cement slurry.The limited expansive rate increases firstly and then decreases with age.Water-solid ratio has the greatest influence on the limited expansive rate.Then,it is the expansion agent dosage and the influence of the clay content is the smallest.Furthermore,it decreases with the increase of water-solid ratio while increases with the growth of the expansion agent dosage.The reference mix proportion for engineering application is of water-solid ratio as 0.6,the clay content at 15%,water glass at 2%,and the expansion agent at 12%.