a State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China
b University of Chinese Academy of Sciences, Beijing, 100049, China
c School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China
d School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China
e School of Civil Engineering and Archtitecture, Henan University, Kaifeng, 475001, China
2024, 16(3): 1000-1017. doi:10.1016/j.jrmge.2023.05.005
Received: 2023-01-11 / Revised: 2023-03-23 / Accepted: 2023-05-15 / Available online: 2023-06-30
2024, 16(3): 1000-1017.
doi:10.1016/j.jrmge.2023.05.005
Received: 2023-01-11
Revised: 2023-03-23
Accepted: 2023-05-15
Available online: 2023-06-30
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 (CO2) 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 CO2 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 CO2 in soils through mineral carbonation, potentially reducing environmental pollution while meeting urbanization needs.
Keywords: Dredged marine soil, CO2 uptake, Reactive magnesia, Biochar, Ground granulated blast-furnace slag
Chikezie Chimere Onyekwena
Chikezie Chimere Onyekwena is a Civil Engineer specializing in Geotechnical Engineering. He holds a Ph.D. in Geotechnical Engineering from the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. He is an active member of the American Society of Civil Engineers (ASCE) and currently serves as a reviewer for various international journals. His research interests include flow through porous media and the stabilization of soft soils, with a focus on developing innovative, low-carbon, and functional construction products with high performance and durability. He is also experienced in using AI tools for advanced engineering computations.