Authors: MingLi Wei YanJun Du Krishna R Reddy Haoliang Wu
Publish Date: 2015/08/11
Volume: 22, Issue: 24, Pages: 19473-19484
Abstract
For viable and sustainable reuse of solidified/stabilized heavy metalcontaminated soils as roadway subgrade materials longterm durability of these soils should be ensured A new binder KMP has been developed for solidifying/stabilizing soils contaminated with high concentrations of heavy metals However the effects of longterm extreme weather conditions including freeze and thaw on the leachability and strength of the KMP stabilized contaminated soils have not been investigated This study presents a systematic investigation on the impacts of freezethaw cycle on leachability strength and microstructural characteristics of the KMP stabilized soils spiked with Zn and Pb individually and together For comparison purpose Portland cement is also tested as a conventional binder Several series of tests are conducted including the toxicity characteristic leaching procedure TCLP modified European Community Bureau of Reference BCR sequential extraction procedure unconfined compression test UCT and mercury intrusion porosimetry MIP The results demonstrate that the freezethaw cycles have much less impact on the leachability and strength of the KMP stabilized soils as compared to the PC stabilized soils After the freezethaw cycle tests the KMP stabilized soils display much lower leachability mass loss and strength loss These results are assessed based on the chemical speciation of Zn and Pb and pore size distribution of the soils Overall this study demonstrates that the KMP stabilized heavy metalcontaminated soils perform well under the freezethaw conditionsThis research is financially supported by the National Natural Science Foundation of China grant no 51278100 41330641 and 41472258 Natural Science Foundation of Jiangsu Province grant no BK2012022 and National High Technology Research and Development Program of China grant no 2013AA06A206 The authors thank the former graduate student Mr J J Zhu for conducting some of the laboratory tests
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