水泥窑灰(CKD)改性膨胀土的胀-缩特性试验研究  

An experimental study of expansion-shrinkage characteristics of cement-kiln-dust-treated expansive soil

作　　者：崔素丽[1] 延恺 王安国[1] 田明锦 

机构地区：[1]西北大学地质学系/大陆动力学国家重点实验室,陕西西安710069

出　　处：《水文地质工程地质》2015年第5期102-106,共5页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助项目(41402260);西北大学大陆动力学国家重点实验自主研究课题

摘　　要：通过向膨胀土中添加2%-18%不同比率的水泥窑灰（CKD）对其进行改性,对纯膨胀土及掺CKD改性膨胀土的水理性质、膨胀特性和收缩特性进行室内试验,确定改性效果。试验结果表明,CKD可以降低膨胀土的自由膨胀率和液限,液限降低规律符合指数函数,塑限略有提高;随着CKD掺量的增大,混合物的最大膨胀率和最大膨胀力均呈指数衰减,最终收缩率也大幅降低。改性后的膨胀土黏粒减少,水稳性提高,同时由于离子交换等作用,膨胀土-CKD混合物的亲水性降低,吸水性减弱,从而胀缩性质降低,说明CKD对降低膨胀土的胀缩特性具有很好的改性效果,建议适宜掺灰率为10%。Cement kiln dust （CKD） is used as an additive for improving expansive soil, and the CKD content ranges from 2% to 18%. Laboratory tests were conducted on compacted mixtures of expansive soil-CKD for water properties, expansion and shrinkage properties in order to determine the improvement effects. The test results show that CKD can reduce the rate of free expansion and liquid limit of the expansive soil, which follows the change of an exponential function, while the plastic limit increases slightly. Both the maximum swelling strain and the swelling pressure of the mixture exponentially decrease with the increasing CKD content ratio, the shrinkage also decreases. After improvement, the clay content of the expansive soil decreases, and the hydrated property of the modified soil is enhanced. Meanwhile, due to the ion exchange action, the hydrophilic and hygroscopic properties reduce, resulting in a decrease in the swelling-shrinkage characteristics. The results show that adding CKD can successfully reduce the swelling-shrinkage characteristics and improve the expansive soil. The optimum CKD content ratio of 10% is suggested.

关 键 词：水泥窑灰(CKD) 膨胀土 水理性质 膨胀特性 收缩特性 

分 类 号：TU443[建筑科学—岩土工程]