Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles

Expansive soil is prone to cracks under a drying–wetting cycle environment, which brings many disasters to road engineering. The main purpose of this study is use coal gangue powder to improve expansive soil, in order to reduce its cracks and further explore its micro-pore mechanism. The drying–wett...

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Autores principales:	Hongxing Zhu, Yan Zhang, Zhuhan Li, Xiaoyu Xue
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	expansive soil cracks drying–wetting cycles coal gangue powder micro-pore mechanism roughness Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
Acceso en línea:	https://doaj.org/article/e3139d153fa7402ba60713613723e151
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spelling	oai:doaj.org-article:e3139d153fa7402ba60713613723e1512021-11-11T18:06:52ZStudy on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles10.3390/ma142165461996-1944https://doaj.org/article/e3139d153fa7402ba60713613723e1512021-11-01T00:00:00Zhttps://www.mdpi.com/1996-1944/14/21/6546https://doaj.org/toc/1996-1944Expansive soil is prone to cracks under a drying–wetting cycle environment, which brings many disasters to road engineering. The main purpose of this study is use coal gangue powder to improve expansive soil, in order to reduce its cracks and further explore its micro-pore mechanism. The drying–wetting cycles test is carried out on the soil sample, and the crack parameters of the soil sample are obtained by Matlab and Image J software. The roughness and micro-pore characteristics of the soil samples are revealed by means of the Laser confocal 3D microscope and Mercury intrusion meter. The results show that coal gangue powder reduces the crack area ratio of expansive soil by 48.9%, and the crack initiation time is delayed by at least 60 min. Coal gangue powder can increase the internal roughness of expansive soil. The greater the roughness of the soil, the less cracks in the soil. After six drying–wetting cycles, the porosity and average pore diameter of the improved and expanded soil are reduced by 37% and 30%, respectively, as compared to the plain expansive soil. By analyzing the cumulative pore volume and cumulative pore density parameters of soil samples, it is found that the macro-cracks are caused by the continuous connection and fusion of micro-voids in soil. Coal gangue powder can significantly reduce the proportion of micro-voids, cumulative pore volume, and cumulative pore density in expansive soil, so as to reduce the macro-cracks.Hongxing ZhuYan ZhangZhuhan LiXiaoyu XueMDPI AGarticleexpansive soilcracksdrying–wetting cyclescoal gangue powdermicro-pore mechanismroughnessTechnologyTElectrical engineering. Electronics. Nuclear engineeringTK1-9971Engineering (General). Civil engineering (General)TA1-2040MicroscopyQH201-278.5Descriptive and experimental mechanicsQC120-168.85ENMaterials, Vol 14, Iss 6546, p 6546 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	expansive soil cracks drying–wetting cycles coal gangue powder micro-pore mechanism roughness Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
spellingShingle	expansive soil cracks drying–wetting cycles coal gangue powder micro-pore mechanism roughness Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 Hongxing Zhu Yan Zhang Zhuhan Li Xiaoyu Xue Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
description	Expansive soil is prone to cracks under a drying–wetting cycle environment, which brings many disasters to road engineering. The main purpose of this study is use coal gangue powder to improve expansive soil, in order to reduce its cracks and further explore its micro-pore mechanism. The drying–wetting cycles test is carried out on the soil sample, and the crack parameters of the soil sample are obtained by Matlab and Image J software. The roughness and micro-pore characteristics of the soil samples are revealed by means of the Laser confocal 3D microscope and Mercury intrusion meter. The results show that coal gangue powder reduces the crack area ratio of expansive soil by 48.9%, and the crack initiation time is delayed by at least 60 min. Coal gangue powder can increase the internal roughness of expansive soil. The greater the roughness of the soil, the less cracks in the soil. After six drying–wetting cycles, the porosity and average pore diameter of the improved and expanded soil are reduced by 37% and 30%, respectively, as compared to the plain expansive soil. By analyzing the cumulative pore volume and cumulative pore density parameters of soil samples, it is found that the macro-cracks are caused by the continuous connection and fusion of micro-voids in soil. Coal gangue powder can significantly reduce the proportion of micro-voids, cumulative pore volume, and cumulative pore density in expansive soil, so as to reduce the macro-cracks.
format	article
author	Hongxing Zhu Yan Zhang Zhuhan Li Xiaoyu Xue
author_facet	Hongxing Zhu Yan Zhang Zhuhan Li Xiaoyu Xue
author_sort	Hongxing Zhu
title	Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
title_short	Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
title_full	Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
title_fullStr	Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
title_full_unstemmed	Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles
title_sort	study on crack development and micro-pore mechanism of expansive soil improved by coal gangue under drying–wetting cycles
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/e3139d153fa7402ba60713613723e151
work_keys_str_mv	AT hongxingzhu studyoncrackdevelopmentandmicroporemechanismofexpansivesoilimprovedbycoalgangueunderdryingwettingcycles AT yanzhang studyoncrackdevelopmentandmicroporemechanismofexpansivesoilimprovedbycoalgangueunderdryingwettingcycles AT zhuhanli studyoncrackdevelopmentandmicroporemechanismofexpansivesoilimprovedbycoalgangueunderdryingwettingcycles AT xiaoyuxue studyoncrackdevelopmentandmicroporemechanismofexpansivesoilimprovedbycoalgangueunderdryingwettingcycles
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Study on Crack Development and Micro-Pore Mechanism of Expansive Soil Improved by Coal Gangue under Drying–Wetting Cycles

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