Collaborative pollution and carbon reduction behaviors of carbonated Pb-contaminated soil stabilized with a low-carbon binder derived from waste concrete  

作　　者：Fangyuan Mu Zhiqiang Ji Lei Lang Zihan Ma Wei Zhang Zhaorong Zhang Jiang-Shan Li 

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China [2]Department of Civil Engineering,Yantai University,Yantai,264005,China [3]Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hung Hom,Kowloon,Hong Kong,China [4]IRSM-CAS/HK PolyU Joint Laboratory on Solid Waste Science,Wuhan,430071,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第3期1770-1785,共16页岩石力学与岩土工程学报(英文)

基　　金：the National Natural Science Foundation of China(Grant Nos.42177163 and 42071080);the China Postdoctoral Science Foundation(Grant No.2022M723347).

摘　　要：Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.

关 键 词：Waste concrete powder(WCP) CARBONATION Lead-contaminated soil Microstructure Conductivity model 

分 类 号：TG1[金属学及工艺—金属学]