Soils exhibit undesirable volume changes when exposed to high concentrations of acids, which is manifested most frequently in the beds of foundations of industrial establishments associated with their production or use. However, control of this phenomenon has received less attention than it deserves. This paper aims to investigate the mineralogical and micro-structural changes occurred during the volume change behavior of phosphogypsum treated clayey soils contaminated with sulfuric acid and phosphoric acid solutions. Oedometer test results showed high swelling and low compressibility for acid contaminated soils than that of water. The change in microstructure towards flocculated fabric along with mineralogical transformations are responsible for the volume changes in soils. The mineralogical changes that affected the volume change behavior are discussed with FT-IR, XRD and SEM analysis. Phosphogypsum treatment was found to be effective in controlling volume changes in soils with phosphoric acid, whereas in the case of sulfuric acid found to be futile.

中文翻译：

---

被无机酸污染的磷石膏处理的粘土的体积变化行为——一项微观研究

当暴露于高浓度酸时，土壤会表现出不希望有的体积变化，这在与其生产或使用相关的工业设施的地基中最为常见。然而，对这种现象的控制受到的关注却比应有的要少。本文旨在研究被硫酸和磷酸溶液污染的磷石膏处理的粘土在体积变化行为过程中发生的矿物学和微观结构变化。Oedometer 测试结果表明，与水相比，酸性污染土壤具有高膨胀性和低压缩性。絮状织物的微观结构变化以及矿物学转变是造成土壤体积变化的原因。用 FT-IR、XRD 和 SEM 分析讨论了影响体积变化行为的矿物学变化。磷石膏处理被发现可以有效地控制含磷酸的土壤体积变化，而在硫酸的情况下则无效。