{"title":"用Soma粉煤灰稳定含硫酸盐膨胀粘土","authors":"Mehmet As, Erdal Cokca","doi":"10.1007/s12517-025-12315-0","DOIUrl":null,"url":null,"abstract":"<div><p>Stabilization of an expansive soil containing sulfate with lime fails to effectively mitigate the swelling behavior of these soils as a result of the occurrence of ettringite, a highly expansive mineral. This study evaluated the effectiveness of utilizing 15% Soma fly ash (SFA) as an alternative to 4% lime (L) in enhancing the stability of expansive soil containing sulfate (SO<sub>4</sub>) against swelling. Maximum allowable SO<sub>4</sub> content for the stabilization of the expansive sulfate clay with SFA was investigated to achieve the greatest reduction in swell potential and simultaneously inhibit the formation of ettringite. Index, swelling, and unconfined compressive strength (UCS) tests, together with scanning electron microscope (SEM) views and X-ray diffraction (XRD) analysis, were used to assess the impact of fly ash on the behavior of sulfate-bearing expansive soil. SO<sub>4</sub> concentration exhibited varying effects on the swell potential of treated specimens. A noticeable increase in the swell potential of expansive sulfate clay was observed when treated with 4% L, but no significant increase was observed when treated with 15% SFA. The UCS of the expansive sulfate clay specimens treated with both additives generally decreased. A significant reduction in strength was recorded for expansive sulfate clay treated with 15% SFA and exposed to 27,000 ppm SO<sub>4</sub> when cured at 10 °C, primarily due to ettringite/thaumasite and thenardite formation. The results indicated that 15% SFA can be safely used for stabilizing expansive soils containing SO<sub>4</sub> without causing heave or durability problems, provided that the SO<sub>4</sub> concentration of the expansive soil is below the threshold level of 6750 ppm.</p></div>","PeriodicalId":476,"journal":{"name":"Arabian Journal of Geosciences","volume":"18 9","pages":""},"PeriodicalIF":1.8270,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Stabilization of an expansive clay containing sulfate with Soma fly ash\",\"authors\":\"Mehmet As, Erdal Cokca\",\"doi\":\"10.1007/s12517-025-12315-0\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Stabilization of an expansive soil containing sulfate with lime fails to effectively mitigate the swelling behavior of these soils as a result of the occurrence of ettringite, a highly expansive mineral. This study evaluated the effectiveness of utilizing 15% Soma fly ash (SFA) as an alternative to 4% lime (L) in enhancing the stability of expansive soil containing sulfate (SO<sub>4</sub>) against swelling. Maximum allowable SO<sub>4</sub> content for the stabilization of the expansive sulfate clay with SFA was investigated to achieve the greatest reduction in swell potential and simultaneously inhibit the formation of ettringite. Index, swelling, and unconfined compressive strength (UCS) tests, together with scanning electron microscope (SEM) views and X-ray diffraction (XRD) analysis, were used to assess the impact of fly ash on the behavior of sulfate-bearing expansive soil. SO<sub>4</sub> concentration exhibited varying effects on the swell potential of treated specimens. A noticeable increase in the swell potential of expansive sulfate clay was observed when treated with 4% L, but no significant increase was observed when treated with 15% SFA. The UCS of the expansive sulfate clay specimens treated with both additives generally decreased. A significant reduction in strength was recorded for expansive sulfate clay treated with 15% SFA and exposed to 27,000 ppm SO<sub>4</sub> when cured at 10 °C, primarily due to ettringite/thaumasite and thenardite formation. The results indicated that 15% SFA can be safely used for stabilizing expansive soils containing SO<sub>4</sub> without causing heave or durability problems, provided that the SO<sub>4</sub> concentration of the expansive soil is below the threshold level of 6750 ppm.</p></div>\",\"PeriodicalId\":476,\"journal\":{\"name\":\"Arabian Journal of Geosciences\",\"volume\":\"18 9\",\"pages\":\"\"},\"PeriodicalIF\":1.8270,\"publicationDate\":\"2025-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Arabian Journal of Geosciences\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s12517-025-12315-0\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"Earth and Planetary Sciences\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Arabian Journal of Geosciences","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1007/s12517-025-12315-0","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Earth and Planetary Sciences","Score":null,"Total":0}
Stabilization of an expansive clay containing sulfate with Soma fly ash
Stabilization of an expansive soil containing sulfate with lime fails to effectively mitigate the swelling behavior of these soils as a result of the occurrence of ettringite, a highly expansive mineral. This study evaluated the effectiveness of utilizing 15% Soma fly ash (SFA) as an alternative to 4% lime (L) in enhancing the stability of expansive soil containing sulfate (SO4) against swelling. Maximum allowable SO4 content for the stabilization of the expansive sulfate clay with SFA was investigated to achieve the greatest reduction in swell potential and simultaneously inhibit the formation of ettringite. Index, swelling, and unconfined compressive strength (UCS) tests, together with scanning electron microscope (SEM) views and X-ray diffraction (XRD) analysis, were used to assess the impact of fly ash on the behavior of sulfate-bearing expansive soil. SO4 concentration exhibited varying effects on the swell potential of treated specimens. A noticeable increase in the swell potential of expansive sulfate clay was observed when treated with 4% L, but no significant increase was observed when treated with 15% SFA. The UCS of the expansive sulfate clay specimens treated with both additives generally decreased. A significant reduction in strength was recorded for expansive sulfate clay treated with 15% SFA and exposed to 27,000 ppm SO4 when cured at 10 °C, primarily due to ettringite/thaumasite and thenardite formation. The results indicated that 15% SFA can be safely used for stabilizing expansive soils containing SO4 without causing heave or durability problems, provided that the SO4 concentration of the expansive soil is below the threshold level of 6750 ppm.
期刊介绍:
The Arabian Journal of Geosciences is the official journal of the Saudi Society for Geosciences and publishes peer-reviewed original and review articles on the entire range of Earth Science themes, focused on, but not limited to, those that have regional significance to the Middle East and the Euro-Mediterranean Zone.
Key topics therefore include; geology, hydrogeology, earth system science, petroleum sciences, geophysics, seismology and crustal structures, tectonics, sedimentology, palaeontology, metamorphic and igneous petrology, natural hazards, environmental sciences and sustainable development, geoarchaeology, geomorphology, paleo-environment studies, oceanography, atmospheric sciences, GIS and remote sensing, geodesy, mineralogy, volcanology, geochemistry and metallogenesis.