Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay
Clay is found in some countries all over the world. It usually has low compressive strength and cannot be used as a bearing material for subgrade soil. In this paper, the influence of basicity on a metakaolin-based polymer binder to improve clay was studied. The effects of the molar concentration of...
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MDPI AG
2022-07-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/15/4805 |
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| author | Xianzeng Shi Qingkun Zha Shuqing Li Guojun Cai Dun Wu Chaojiao Zhai |
| author_facet | Xianzeng Shi Qingkun Zha Shuqing Li Guojun Cai Dun Wu Chaojiao Zhai |
| author_sort | Xianzeng Shi |
| collection | DOAJ |
| description | Clay is found in some countries all over the world. It usually has low compressive strength and cannot be used as a bearing material for subgrade soil. In this paper, the influence of basicity on a metakaolin-based polymer binder to improve clay was studied. The effects of the molar concentration of the alkali activator, different concentration of the metakaolin-based geopolymer and curing time on unconfined compressive strength were studied. The alkali activator-to-ash ratio was maintained at 0.7. The percentage of metakaolin added to the soil relative to metakaolin and soil mixture was 6%, 8%, 10% and 12%. The sodium hydroxide concentrations are 2M, 4M, 6M and 8M. Unconfined compressive strength (UCS) was tested on days 3, 7, 14 and 28, respectively. Compared with original clay, the results show that the unconfined compressive strength increases with the increase in metakaolin content and molar concentration of NaOH. The maximum compressive strength of the sample with NaOH concentration of 8M and percentage of 12% was 4109 kN on the 28th day, which is about 112% higher than that of the original clay. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results showed that the cementing compound covered the clay particles due to the reaction of the geopolymer with the clay, resulting in the formation of adhesive particles. The main purpose of this study is to verify the effectiveness and stability of metakaolin-based geopolymer binder polymerization under normal temperature and a strong alkali environment. The results can provide parameters for the application and promotion of metakaolin-based geopolymers in soil improvement engineering. |
| first_indexed | 2024-03-09T05:11:10Z |
| format | Article |
| id | doaj.art-90533f7170884c36ad826b93b5595646 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T05:11:10Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-90533f7170884c36ad826b93b55956462023-12-03T12:49:48ZengMDPI AGMolecules1420-30492022-07-012715480510.3390/molecules27154805Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified ClayXianzeng Shi0Qingkun Zha1Shuqing Li2Guojun Cai3Dun Wu4Chaojiao Zhai5Key Laboratory of Intelligent Underground Detection Technology, Anhui Province Key Laboratory of Advanced Building Materials, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, ChinaKey Laboratory of Intelligent Underground Detection Technology, Anhui Province Key Laboratory of Advanced Building Materials, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, ChinaSinosteel Maanshan General Institute of Mining Research Co., Ltd., Maanshan 243000, ChinaKey Laboratory of Intelligent Underground Detection Technology, Anhui Province Key Laboratory of Advanced Building Materials, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, ChinaKey Laboratory of Intelligent Underground Detection Technology, Anhui Province Key Laboratory of Advanced Building Materials, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, ChinaKey Laboratory of Intelligent Underground Detection Technology, Anhui Province Key Laboratory of Advanced Building Materials, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, ChinaClay is found in some countries all over the world. It usually has low compressive strength and cannot be used as a bearing material for subgrade soil. In this paper, the influence of basicity on a metakaolin-based polymer binder to improve clay was studied. The effects of the molar concentration of the alkali activator, different concentration of the metakaolin-based geopolymer and curing time on unconfined compressive strength were studied. The alkali activator-to-ash ratio was maintained at 0.7. The percentage of metakaolin added to the soil relative to metakaolin and soil mixture was 6%, 8%, 10% and 12%. The sodium hydroxide concentrations are 2M, 4M, 6M and 8M. Unconfined compressive strength (UCS) was tested on days 3, 7, 14 and 28, respectively. Compared with original clay, the results show that the unconfined compressive strength increases with the increase in metakaolin content and molar concentration of NaOH. The maximum compressive strength of the sample with NaOH concentration of 8M and percentage of 12% was 4109 kN on the 28th day, which is about 112% higher than that of the original clay. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results showed that the cementing compound covered the clay particles due to the reaction of the geopolymer with the clay, resulting in the formation of adhesive particles. The main purpose of this study is to verify the effectiveness and stability of metakaolin-based geopolymer binder polymerization under normal temperature and a strong alkali environment. The results can provide parameters for the application and promotion of metakaolin-based geopolymers in soil improvement engineering.https://www.mdpi.com/1420-3049/27/15/4805claymetakaolingeopolymersodium hydroxide (NaOH)unconfined compressive strengthscanning electron microscopy (SEM) |
| spellingShingle | Xianzeng Shi Qingkun Zha Shuqing Li Guojun Cai Dun Wu Chaojiao Zhai Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay Molecules clay metakaolin geopolymer sodium hydroxide (NaOH) unconfined compressive strength scanning electron microscopy (SEM) |
| title | Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay |
| title_full | Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay |
| title_fullStr | Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay |
| title_full_unstemmed | Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay |
| title_short | Experimental Study on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymer Modified Clay |
| title_sort | experimental study on the mechanical properties and microstructure of metakaolin based geopolymer modified clay |
| topic | clay metakaolin geopolymer sodium hydroxide (NaOH) unconfined compressive strength scanning electron microscopy (SEM) |
| url | https://www.mdpi.com/1420-3049/27/15/4805 |
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