首页|Efficient stabilization of dredged sludge with high water content using an improved bio-carbonation of reactive magnesia cement method

Efficient stabilization of dredged sludge with high water content using an improved bio-carbonation of reactive magnesia cement method

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This study proposed an improved bio-carbonation of reactive magnesia cement(RMC)method for dredged sludge stabilization using the urea pre-hydrolysis strategy.Based on unconfined compression strength(UCS),pickling-drainage,and scanning electron microscopy(SEM)tests,the effects of pre-hydrolysis duration(T),urease activity(UA)and curing age(CA)on the mechanical properties and microstructural characteristics of bio-carbonized samples were systematically investigated and analyzed.The results demonstrated that the proposed method could significantly enhance urea hydrolysis and RMC bio-carbonation to achieve efficient stabilization of dredged sludge with 80％high water content.A significant strength increment of up to about 1063.36 kPa was obtained for the bio-carbonized samples after just 7 d of curing,which was 2.64 times higher than that of the 28-day cured ordinary Portland cement-reinforced samples.Both elevated T and UA could notably increase urea utilization ratio and carbonate ion yield,but the resulting surge in supersaturation also affected the precipitation patterns of hydrated magnesia carbonates(HMCs),which weakened the cementation effect of HMCs on soil particles and further inhibited strength enhancement of bio-carbonized samples.The optimum formula was determined to be the case of T=24 h and UA=10 U/mL for dredged sludge stabilization.A 7-day CA was enough for bio-carbonized samples to obtain stable strength,albeit slightly affected by UA.The benefits of high efficiency and water stability presented the potential of this method in achieving dredged sludge stabilization and resource utilization.This investigation provides informative ideas and valuable insights on implementing advanced bio-geotechnical techniques to achieve efficient stabilization of soft soil,such as dredged sludge.

Reactive magnesia cement(RMC)bio-carbonationUrea pre-hydrolysisDredged sludgeEfficient stabilizationUnconfined compressive strengthMicrobially induced carbonate precipitation(MICP)

Rui Wang、Chaosheng Tang、Xiaohua Pan、Dianlong Wang、Zhihao Dong、Xiying Zhang、Xiancai Lu

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School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China

Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lake,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining,810008,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaKey Laboratory Cooperation Special Project of Western Cross Team of Western Light,CAS

4192501242230710xbzgzdsys-202107

2024

10.1016/j.jrmge.2023.12.030

岩石力学与岩土工程学报(英文版)
中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD
影响因子：0.404
ISSN：1674-7755
年,卷(期)：2024.16(9)