Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization
Calcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the optimal stimulation so...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-12-01
|
| Series: | Materials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1944/16/1/251 |
| _version_ | 1797625436944990208 |
|---|---|
| author | Gangqiang Shen Shiyu Liu Yuhan He Muzhi Pan Jin Yu Yanyan Cai |
| author_facet | Gangqiang Shen Shiyu Liu Yuhan He Muzhi Pan Jin Yu Yanyan Cai |
| author_sort | Gangqiang Shen |
| collection | DOAJ |
| description | Calcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the optimal stimulation solution was obtained with response surface methodology. Then, the effect of reinforcing calcareous sand was analysed with unconfined compressive strength (UCS) tests, calcium carbonate content tests, microscopy and microbial community analyses. The components and concentrations of the optimal stimulation solution were as follows: sodium acetate (38.00 mM), ammonium chloride (124.24 mM), yeast extract (0.46 g/L), urea (333 mM), and nickel chloride (0.01 mM), and the pH was 8.75. After the calcareous sand was treated with the optimal stimulation scheme, the urease activity was 6.1891 mM urea/min, the calcium carbonate production was 8.40%, and the UCS was 770 kPa, which constituted increases of 71.41%, 35.40%, and 83.33%, respectively, compared with the initial scheme. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses showed that calcium carbonate crystals were formed between the particles of the calcareous sand after the reaction, and the calcium carbonate crystals were mainly calcite. Urease-producing microorganisms became the dominant species in calcareous sand after treatment. This study showed that biostimulation-induced mineralization is feasible for reinforcing calcareous sand. |
| first_indexed | 2024-03-11T09:56:28Z |
| format | Article |
| id | doaj.art-f27689a68f324655bb84be2d5e6fd4dc |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T09:56:28Z |
| publishDate | 2022-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-f27689a68f324655bb84be2d5e6fd4dc2023-11-16T15:49:06ZengMDPI AGMaterials1996-19442022-12-0116125110.3390/ma16010251Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced MineralizationGangqiang Shen0Shiyu Liu1Yuhan He2Muzhi Pan3Jin Yu4Yanyan Cai5Fujian Research Center for Tunneling and Urban Underground Space Engineering, Huaqiao University, Xiamen 361021, ChinaFujian Research Center for Tunneling and Urban Underground Space Engineering, Huaqiao University, Xiamen 361021, ChinaFujian Research Center for Tunneling and Urban Underground Space Engineering, Huaqiao University, Xiamen 361021, ChinaFujian Water Conservancy and Hydropower Engineering Bureau Company Limited, Quanzhou 362000, ChinaFujian Research Center for Tunneling and Urban Underground Space Engineering, Huaqiao University, Xiamen 361021, ChinaFujian Research Center for Tunneling and Urban Underground Space Engineering, Huaqiao University, Xiamen 361021, ChinaCalcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the optimal stimulation solution was obtained with response surface methodology. Then, the effect of reinforcing calcareous sand was analysed with unconfined compressive strength (UCS) tests, calcium carbonate content tests, microscopy and microbial community analyses. The components and concentrations of the optimal stimulation solution were as follows: sodium acetate (38.00 mM), ammonium chloride (124.24 mM), yeast extract (0.46 g/L), urea (333 mM), and nickel chloride (0.01 mM), and the pH was 8.75. After the calcareous sand was treated with the optimal stimulation scheme, the urease activity was 6.1891 mM urea/min, the calcium carbonate production was 8.40%, and the UCS was 770 kPa, which constituted increases of 71.41%, 35.40%, and 83.33%, respectively, compared with the initial scheme. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses showed that calcium carbonate crystals were formed between the particles of the calcareous sand after the reaction, and the calcium carbonate crystals were mainly calcite. Urease-producing microorganisms became the dominant species in calcareous sand after treatment. This study showed that biostimulation-induced mineralization is feasible for reinforcing calcareous sand.https://www.mdpi.com/1996-1944/16/1/251native microorganismsstimulation solutioncalcareous sandresponse surface methodologyurease activity |
| spellingShingle | Gangqiang Shen Shiyu Liu Yuhan He Muzhi Pan Jin Yu Yanyan Cai Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization Materials native microorganisms stimulation solution calcareous sand response surface methodology urease activity |
| title | Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization |
| title_full | Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization |
| title_fullStr | Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization |
| title_full_unstemmed | Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization |
| title_short | Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization |
| title_sort | reinforcement of calcareous sands by stimulation of native microorganisms induced mineralization |
| topic | native microorganisms stimulation solution calcareous sand response surface methodology urease activity |
| url | https://www.mdpi.com/1996-1944/16/1/251 |
| work_keys_str_mv | AT gangqiangshen reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization AT shiyuliu reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization AT yuhanhe reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization AT muzhipan reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization AT jinyu reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization AT yanyancai reinforcementofcalcareoussandsbystimulationofnativemicroorganismsinducedmineralization |