Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess
Collapsible loess poses significant geotechnical risks due to its metastable structure and water sensitivity, while conventional stabilization methods often lack sustainability. This study investigates the synergistic effects of microbial-induced carbonate precipitation (MICP) and modified biochar (...
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MDPI AG
2025-05-01
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| Online Access: | https://www.mdpi.com/2073-4352/15/6/504 |
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| author | Qibo Yan Lingwei Kong Shiyue Fang |
| author_facet | Qibo Yan Lingwei Kong Shiyue Fang |
| author_sort | Qibo Yan |
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| description | Collapsible loess poses significant geotechnical risks due to its metastable structure and water sensitivity, while conventional stabilization methods often lack sustainability. This study investigates the synergistic effects of microbial-induced carbonate precipitation (MICP) and modified biochar (MBC) to enhance loess engineering properties. Controlled experiments evaluated hydraulic conductivity, shear strength, and stress-strress–strain behavior under varying MBC content (0–8%), cementation reagent concentration (0.5–1.5 mol/L), and confining pressures (50–400 kPa), and complemented by microstructural characterization via scanning electron microscope (SEM). Results demonstrate that MBC (4–6%) optimizes calcium carbonate distribution by providing nucleation sites, reducing hydraulic conductivity by 72% and increasing shear strength by 52% when compared with untreated loess. Elevated confining pressures (200–400 kPa) transformed brittle failure into ductile behavior through particle interlocking, with peak strength quadrupling under 400 kPa. SEM analysis revealed MBC stabilizes hierarchical pore networks: macropores sustain microbial activity, while mesopores are occluded by CaCO<sub>3</sub>-MBC composites, sequestering ionic byproducts to mitigate efflorescence. The optimal combination (6% MBC, 1.0 mol/L reagent, 200 kPa confinement) achieved 85% of maximum strength gain at reduced reagent cost, balancing performance and sustainability. |
| format | Article |
| id | doaj-art-a0b5d88500d14fcf8b2fec25e2455a39 |
| institution | Kabale University |
| issn | 2073-4352 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
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| series | Crystals |
| spelling | doaj-art-a0b5d88500d14fcf8b2fec25e2455a392025-08-20T03:27:01ZengMDPI AGCrystals2073-43522025-05-0115650410.3390/cryst15060504Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of LoessQibo Yan0Lingwei Kong1Shiyue Fang2College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, ChinaNorthwest Research Institute Co., Ltd. of China Railway Engineering Corporation, Lanzhou 730000, ChinaCollege of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, ChinaCollapsible loess poses significant geotechnical risks due to its metastable structure and water sensitivity, while conventional stabilization methods often lack sustainability. This study investigates the synergistic effects of microbial-induced carbonate precipitation (MICP) and modified biochar (MBC) to enhance loess engineering properties. Controlled experiments evaluated hydraulic conductivity, shear strength, and stress-strress–strain behavior under varying MBC content (0–8%), cementation reagent concentration (0.5–1.5 mol/L), and confining pressures (50–400 kPa), and complemented by microstructural characterization via scanning electron microscope (SEM). Results demonstrate that MBC (4–6%) optimizes calcium carbonate distribution by providing nucleation sites, reducing hydraulic conductivity by 72% and increasing shear strength by 52% when compared with untreated loess. Elevated confining pressures (200–400 kPa) transformed brittle failure into ductile behavior through particle interlocking, with peak strength quadrupling under 400 kPa. SEM analysis revealed MBC stabilizes hierarchical pore networks: macropores sustain microbial activity, while mesopores are occluded by CaCO<sub>3</sub>-MBC composites, sequestering ionic byproducts to mitigate efflorescence. The optimal combination (6% MBC, 1.0 mol/L reagent, 200 kPa confinement) achieved 85% of maximum strength gain at reduced reagent cost, balancing performance and sustainability.https://www.mdpi.com/2073-4352/15/6/504microbial-induced carbonate precipitation (MICP)modified biochar (MBC)loess stabilizationengineering propertiesmicrostructural analysis |
| spellingShingle | Qibo Yan Lingwei Kong Shiyue Fang Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess Crystals microbial-induced carbonate precipitation (MICP) modified biochar (MBC) loess stabilization engineering properties microstructural analysis |
| title | Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess |
| title_full | Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess |
| title_fullStr | Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess |
| title_full_unstemmed | Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess |
| title_short | Synergistic Effects of Microbial-Induced Carbonate Precipitation and Modified Biochar on the Engineering Properties of Loess |
| title_sort | synergistic effects of microbial induced carbonate precipitation and modified biochar on the engineering properties of loess |
| topic | microbial-induced carbonate precipitation (MICP) modified biochar (MBC) loess stabilization engineering properties microstructural analysis |
| url | https://www.mdpi.com/2073-4352/15/6/504 |
| work_keys_str_mv | AT qiboyan synergisticeffectsofmicrobialinducedcarbonateprecipitationandmodifiedbiocharontheengineeringpropertiesofloess AT lingweikong synergisticeffectsofmicrobialinducedcarbonateprecipitationandmodifiedbiocharontheengineeringpropertiesofloess AT shiyuefang synergisticeffectsofmicrobialinducedcarbonateprecipitationandmodifiedbiocharontheengineeringpropertiesofloess |