Dredged marine soil stabilization using magnesia cement augmented with biochar/slag  

作　　者：Chikezie Chimere Onyekwena Qi Li Yong Wang Ishrat Hameed Alvi Wentao Li Yunlu Hou Xianwei Zhang Min Zhang 

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]University of Chinese Academy of Sciences,Beijing,100049,China [3]School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan,430068,China [4]School of Urban Construction,Wuhan University of Science and Technology,Wuhan,430065,China [5]School of Civil Engineering and Archtitecture,Henan University,Kaifeng,475001,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第3期1000-1017,共18页岩石力学与岩土工程学报（英文版）

基　　金：This work was supported by the Creative Groups of Natural Science Foundation of Hubei Province(Grant No.2021CFA030).Onyekwena Chikezie Chimere is an awardee for the ANSO Scholarship 2020-PhD.Ishrat Hameed Alvi is a recipient of the 2021 PhD ANSO Scholarship.

摘　　要：Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.

关 键 词：Dredged marine soil CO_(2)uptake Reactive magnesia BIOCHAR Ground granulated blast-furnace slag 

分 类 号：TU47[建筑科学—结构工程]