农业环境科学学报2017，Vol.36Issue(4)：686-693,8.DOI:10.11654/jaes.2016-1552
镉污染土在水泥-粉煤灰-石灰共同作用下固化效果及孔隙特征
Curing effect and pore characteristics of cadmium contaminated soil under the action of cement-fly ash-lime
摘要
Abstract
The Stabilization and Solidification(S/S)method is one of the common methods currently applied in treatment of heavy metal con-taminated sites. Application of S/S will not only improve the strength of the contaminated soil but also stabilize and solidify the heavy metal ions in the soil so that the same can be reused as fillings for shallow roadbed or foundation. Based on S/S-related technology and research, we added cadmium nitrate(Cd2+)into the soil to simulate the contaminated soil, and then, according to the design of the orthogonal test, the soil was mixed with curing agent composed of cement, fly ash, lime, each in different amounts, and then put under compaction molding for 7 d, 28 d, 60 d, 90 d. By studying the unconfined compressive strength, concentration of trickle-leaching heavy metals and the range and pro-portion of post-curing pore sizes, this paper explores how different cadmium ion concentration, mixing amount/ratio of curing agent and cur-ing age affect the soil tested. The test results showed that with the increase of curing agent dosage and curing age, unconfined strength of the soil was significantly enhanced while heavy metal leaching rate were decreasing to a more stable state;the most influential factor on curing strength is cement content;best curing strength can be achieved with the mixing ratio of 8%(cement), 6%(fly ash), 6%(lime);in the case of 28 d solidification, the pore sizes were mainly in the range of 0.01∽1 μm, indicating compact soil structure; higher proportion of pores over 10μm in diameter will result in lower strength and higher concentration of trickle-leaching heavy metals, both of which are not con-ducive to using curing-hydration products for filling purposes.关键词
镉污染/水泥/粉煤灰/石灰/固化/无侧限抗压强度/淋滤/孔隙Key words
cadmium pollution/cement/fly ash/lime/curing/unconfined compressive strength/leaching/porosity分类
资源环境引用本文复制引用
韩超,申向东,薛慧君,樊浩伦,王仁远,刘倩,刘政..镉污染土在水泥-粉煤灰-石灰共同作用下固化效果及孔隙特征[J].农业环境科学学报,2017,36(4):686-693,8.基金项目
国家自然科学基金项目(51569021) （51569021）
内蒙古自治区博士研究生科研创新重点项目(B20161012908Z) The National Natural Science Foundation of China(51569021) （B20161012908Z）
The Key Project Supported by Program of Research and Innovation for Doctoral Camdidate of Inner Mongolia(B20161012908Z) （B20161012908Z）
