Mechanical properties and microscopic characteristics of fly ash–slag composite backfill
Abstract The strength of the backfill is crucial for safe and efficient mining, and the cementing material is the key to obtaining a strong backfill. In this paper, industrial waste was used as a raw material, into which basis basalt fibres of different lengths and dosages were incorporated. First,...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Springer
2023-10-01
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| Series: | Geomechanics and Geophysics for Geo-Energy and Geo-Resources |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s40948-023-00664-7 |
| _version_ | 1797659813090426880 |
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| author | Xuefeng Zhang Xiangdong Zhang Pang Shuai Lijuan Su Guanjun Cai |
| author_facet | Xuefeng Zhang Xiangdong Zhang Pang Shuai Lijuan Su Guanjun Cai |
| author_sort | Xuefeng Zhang |
| collection | DOAJ |
| description | Abstract The strength of the backfill is crucial for safe and efficient mining, and the cementing material is the key to obtaining a strong backfill. In this paper, industrial waste was used as a raw material, into which basis basalt fibres of different lengths and dosages were incorporated. First, the influencing factors were determined through orthogonal test designs. The optimal ratio of solid–liquid ratio of 2 and basalt fiber content of 2% and length of 6 mm was obtained, and thereby the complete proportion of the backfill material was obtained. The compressive strength and slump of the backfill material mixed with basalt fibres were investigated, and the interfacial mechanism of the backfill material was analysed at the microscopic level using scanning electron microscopy and X-ray diffraction. The results indicated that the degrees of influence of the different factors on the mechanical properties of the backfill material decreased in the following order: Solid–liquid ratio > fibre dosage > fibre length. Furthermore, there were different degrees of interaction among them. Under the best test proportion, that is, when the Solid–liquid ratio was 2, the fibre dosage was 2%, and the fibre length was 6 mm, the slump was 210 mm, and the compressive strength was 5.03 MPa. The mechanical properties were the best at this time. Through data regression, the relationship between the fibre dosage and the average peak stress was established, and the full curve expression for the uniaxial compressive stress–strain of the BFGF specimen was obtained. According to a microscopic characterisation analysis, the slag formed C–S–H gel, which contributed to the early-stage strength of the filling material; fly ash and coal gangue contained a large amount of aluminium, which formed hydrated aluminosilicate with a framework structure, and this contributed significantly to the later-stage strength of the backfill material. The addition of basalt fibres reduces the internal defects of the backfill, allowing the internal pore structure of the backfill to be optimised and the compressive strength to be increased. The results of this study have been successfully implemented in actual projects. Additionally, they provide a reference for similar mine management projects and have considerable promotion and application value. |
| first_indexed | 2024-03-11T18:21:38Z |
| format | Article |
| id | doaj.art-f2722fde17b94dfba611f2ff54c291c0 |
| institution | Directory Open Access Journal |
| issn | 2363-8419 2363-8427 |
| language | English |
| last_indexed | 2024-03-11T18:21:38Z |
| publishDate | 2023-10-01 |
| publisher | Springer |
| record_format | Article |
| series | Geomechanics and Geophysics for Geo-Energy and Geo-Resources |
| spelling | doaj.art-f2722fde17b94dfba611f2ff54c291c02023-10-15T11:32:07ZengSpringerGeomechanics and Geophysics for Geo-Energy and Geo-Resources2363-84192363-84272023-10-019111410.1007/s40948-023-00664-7Mechanical properties and microscopic characteristics of fly ash–slag composite backfillXuefeng Zhang0Xiangdong Zhang1Pang Shuai2Lijuan Su3Guanjun Cai4School of Civil Engineering, Liaoning Technical UniversitySchool of Civil Engineering, Liaoning Technical UniversitySchool of Civil Engineering, Liaoning Technical UniversitySchool of Civil Engineering, Liaoning Technical UniversityBeijing Jingneng Geological Engineering Co.LtdAbstract The strength of the backfill is crucial for safe and efficient mining, and the cementing material is the key to obtaining a strong backfill. In this paper, industrial waste was used as a raw material, into which basis basalt fibres of different lengths and dosages were incorporated. First, the influencing factors were determined through orthogonal test designs. The optimal ratio of solid–liquid ratio of 2 and basalt fiber content of 2% and length of 6 mm was obtained, and thereby the complete proportion of the backfill material was obtained. The compressive strength and slump of the backfill material mixed with basalt fibres were investigated, and the interfacial mechanism of the backfill material was analysed at the microscopic level using scanning electron microscopy and X-ray diffraction. The results indicated that the degrees of influence of the different factors on the mechanical properties of the backfill material decreased in the following order: Solid–liquid ratio > fibre dosage > fibre length. Furthermore, there were different degrees of interaction among them. Under the best test proportion, that is, when the Solid–liquid ratio was 2, the fibre dosage was 2%, and the fibre length was 6 mm, the slump was 210 mm, and the compressive strength was 5.03 MPa. The mechanical properties were the best at this time. Through data regression, the relationship between the fibre dosage and the average peak stress was established, and the full curve expression for the uniaxial compressive stress–strain of the BFGF specimen was obtained. According to a microscopic characterisation analysis, the slag formed C–S–H gel, which contributed to the early-stage strength of the filling material; fly ash and coal gangue contained a large amount of aluminium, which formed hydrated aluminosilicate with a framework structure, and this contributed significantly to the later-stage strength of the backfill material. The addition of basalt fibres reduces the internal defects of the backfill, allowing the internal pore structure of the backfill to be optimised and the compressive strength to be increased. The results of this study have been successfully implemented in actual projects. Additionally, they provide a reference for similar mine management projects and have considerable promotion and application value.https://doi.org/10.1007/s40948-023-00664-7Geopolymer fillingCementing materialsBasalt fibresOrthogonal testsMechanical properties |
| spellingShingle | Xuefeng Zhang Xiangdong Zhang Pang Shuai Lijuan Su Guanjun Cai Mechanical properties and microscopic characteristics of fly ash–slag composite backfill Geomechanics and Geophysics for Geo-Energy and Geo-Resources Geopolymer filling Cementing materials Basalt fibres Orthogonal tests Mechanical properties |
| title | Mechanical properties and microscopic characteristics of fly ash–slag composite backfill |
| title_full | Mechanical properties and microscopic characteristics of fly ash–slag composite backfill |
| title_fullStr | Mechanical properties and microscopic characteristics of fly ash–slag composite backfill |
| title_full_unstemmed | Mechanical properties and microscopic characteristics of fly ash–slag composite backfill |
| title_short | Mechanical properties and microscopic characteristics of fly ash–slag composite backfill |
| title_sort | mechanical properties and microscopic characteristics of fly ash slag composite backfill |
| topic | Geopolymer filling Cementing materials Basalt fibres Orthogonal tests Mechanical properties |
| url | https://doi.org/10.1007/s40948-023-00664-7 |
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