Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism
The present work determined the influence of superhydrophobic nano-SiO<sub>2</sub> on the hydraulic conductivity and pore size distribution of expansive soil, and analysed the mechanism of modification between superhydrophobic nano-SiO<sub>2</sub> and expansive soil from a mi...
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MDPI AG
2023-07-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/13/14/8198 |
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| author | Xiaoqian Luo Lingwei Kong Wei Bai |
| author_facet | Xiaoqian Luo Lingwei Kong Wei Bai |
| author_sort | Xiaoqian Luo |
| collection | DOAJ |
| description | The present work determined the influence of superhydrophobic nano-SiO<sub>2</sub> on the hydraulic conductivity and pore size distribution of expansive soil, and analysed the mechanism of modification between superhydrophobic nano-SiO<sub>2</sub> and expansive soil from a microscopic view. Superhydrophobic nano-SiO<sub>2</sub> was added to expansive soil as a modifier. Our samples were of two types, i.e., unmodified (without nano-SiO<sub>2</sub>) and modified (with 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% nano-SiO<sub>2</sub> by weight of the parent soil). The hydraulic conductivity decreased with increasing nano-SiO<sub>2</sub> content. Fourier transform mid-infrared test revealed that some silanols in soil and nano-SiO<sub>2</sub> were dehydrated and condensed to form siloxanes. We inferred that nano-SiO<sub>2</sub> can attach onto the surface of soil particles to form a hydrophobic membrane, which reduced the soil expansion and the change in pore size distribution. And microscopic tests showed that the pore volume and hydrophilicity of the soil samples decreased with increasing SiO<sub>2</sub> content. According to the Young–Laplace equation, the minimum permeable pore radius was calculated in the hydraulic-conductivity test. With increasing nano-SiO<sub>2</sub> content, the volume of permeable pore decreased. It had an excellent linear relationship with the hydraulic conductivity and permeable pore volume of samples containing different nano-SiO<sub>2</sub> contents. Therefore, superhydrophobic nano-SiO<sub>2</sub> could effectively reduce hydraulic conductivity by changing the pore size distribution of expansive soil. |
| first_indexed | 2024-03-11T01:20:37Z |
| format | Article |
| id | doaj.art-6113737df6724148a67e445988dcf420 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-11T01:20:37Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-6113737df6724148a67e445988dcf4202023-11-18T18:09:42ZengMDPI AGApplied Sciences2076-34172023-07-011314819810.3390/app13148198Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its MechanismXiaoqian Luo0Lingwei Kong1Wei Bai2State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaThe present work determined the influence of superhydrophobic nano-SiO<sub>2</sub> on the hydraulic conductivity and pore size distribution of expansive soil, and analysed the mechanism of modification between superhydrophobic nano-SiO<sub>2</sub> and expansive soil from a microscopic view. Superhydrophobic nano-SiO<sub>2</sub> was added to expansive soil as a modifier. Our samples were of two types, i.e., unmodified (without nano-SiO<sub>2</sub>) and modified (with 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% nano-SiO<sub>2</sub> by weight of the parent soil). The hydraulic conductivity decreased with increasing nano-SiO<sub>2</sub> content. Fourier transform mid-infrared test revealed that some silanols in soil and nano-SiO<sub>2</sub> were dehydrated and condensed to form siloxanes. We inferred that nano-SiO<sub>2</sub> can attach onto the surface of soil particles to form a hydrophobic membrane, which reduced the soil expansion and the change in pore size distribution. And microscopic tests showed that the pore volume and hydrophilicity of the soil samples decreased with increasing SiO<sub>2</sub> content. According to the Young–Laplace equation, the minimum permeable pore radius was calculated in the hydraulic-conductivity test. With increasing nano-SiO<sub>2</sub> content, the volume of permeable pore decreased. It had an excellent linear relationship with the hydraulic conductivity and permeable pore volume of samples containing different nano-SiO<sub>2</sub> contents. Therefore, superhydrophobic nano-SiO<sub>2</sub> could effectively reduce hydraulic conductivity by changing the pore size distribution of expansive soil.https://www.mdpi.com/2076-3417/13/14/8198superhydrophobic nano-SiO<sub>2</sub>expansive soilhydraulic conductivitypore size distributionnuclear magnetic resonance |
| spellingShingle | Xiaoqian Luo Lingwei Kong Wei Bai Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism Applied Sciences superhydrophobic nano-SiO<sub>2</sub> expansive soil hydraulic conductivity pore size distribution nuclear magnetic resonance |
| title | Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism |
| title_full | Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism |
| title_fullStr | Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism |
| title_full_unstemmed | Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism |
| title_short | Effect of Superhydrophobic Nano-SiO<sub>2</sub> on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism |
| title_sort | effect of superhydrophobic nano sio sub 2 sub on the hydraulic conductivity of expansive soil and analysis of its mechanism |
| topic | superhydrophobic nano-SiO<sub>2</sub> expansive soil hydraulic conductivity pore size distribution nuclear magnetic resonance |
| url | https://www.mdpi.com/2076-3417/13/14/8198 |
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