a Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
b Department of Geotechnical Engineering, School of Civil Engineering, Tongji University, Shanghai, 200092, China
c College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, 518071, China
2024, 16(12): 5264-5277. doi:10.1016/j.jrmge.2024.02.037
Received: 2023-09-22 / Revised: 2023-12-12 / Accepted: 2024-02-29 / Available online: 2024-06-13
2024, 16(12): 5264-5277.
doi:10.1016/j.jrmge.2024.02.037
Received: 2023-09-22
Revised: 2023-12-12
Accepted: 2024-02-29
Available online: 2024-06-13
This study aims to evaluate the possibility of reusing treated marine clayey soils by stabilization/solidification (S/S) technology as geomaterial in reclamation projects from the aspects of engineering strength, chemical modification and environmental risk assessment. The lime-activated incinerated sewage sludge ash (ISSA) together with ground granulated blast furnace slag (GGBS) was employed as the binder. The multi-controlling factors including water content, curing time, salinity, and chemical compositions of mixing solution were taken into account to identify the S/S treated Hong Kong marine deposit (HKMD) slurry based on the strength tests, pH measurement, thermo-gravimetric (TG) analysis, X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS) and toxicity characteristic leaching procedure (TCLP) tests, etc. The results show that the S/S treatment using lime-activated ISSA-GGBS can effectively enhance the strength of marine soil at the initial water content of 110% and 200%. The water content and curing time have a significant impact on the S/S treated HKMD. The pH of treated soils is higher than 11.1, which proves an alkaline environment for the reactions in the treated soil. A special case is the treated HKMD at 200% water content hydrated by MgCl2 solution, which has a low pH of 10.23 and maintains a slurry state. Based on the TCLP results, the leaching concentration of heavy metals from S/S treated HKMD is environmentally safe and meets Hong Kong standard for reusing treated soil with a low level of <0.2 mg/L. The content of main products such as calcium/magnesium silicate hydrate, ettringite or Friedel's salt depends on the chemical additions (e.g. distilled water, seawater, NaCl and Na2SO4). The products in the specimens mixed with MgCl2 solutions are mainly composed of Mg(OH)2, M-S-H and MgCO3, which is distinct with the neoformations in the other cases. Therefore, this study proves that the S/S treated soil slurry could be reused as geomaterials in reclamation projects, and the S/S process is greatly affected by water content, curing time and solution compositions, etc.
Keywords: Hong Kong marine deposits, Stabilization/solidification, Engineering strength, Physicochemical property, Environmental risk assessment
Zhao Sun, Wenbo Chen, Rundong Zhao, Numan Malik, Jianhua Yin, Yonggui Chen, 2024. Investigation on solidified/stabilized behavior of marine soil slurry by lime-activated incinerated sewage sludge ash-ground granulated blast furnace slag under multifactor conditions. J. Rock Mech. Geotech. Eng. 16 (12), 5264-5277.
Zhao Sun
Dr. Sun received her PhD from Tongji University in China. She received her BEng and MEng from China University of Mining and Technology, Xuzhou, China. She has 10 years of experiences in unsaturated soils, clay and clay minerals, microstructure analysis, geological storage of radioactive waste, soil stabilization, geo-environmental engineering. Her current research focus includes experimental investigations on the chemo-hydro-mechanical behaviors of bentonite and the stabilized/solidified clayey soil. She has published over 16 international journal papers, obtained 2 authorized national invention patents and taken part in a number of technical symposia and international conferences.