Regional characterization and the influence of mineralogy on the swelling of lime-treated expansive soils

The expansive soils pose significant challenges in geotechnical engineering due to their tendency to swell when wet and shrink when dry. They present serious issues and challenges to light structures and pavements. Treatment using hydrated lime is one of the stabilization techniques that is widely used to improve the performance of these soils. This study aims to examine the behavior of volume change for three types of expansive clays from three different locations in Saudi Arabia that are classified as expansive. Experimental work covered lime-treated and untreated clay. The influence of lime content and curing period is monitored. Four lime contents: 2%, 4%, 6%, and 8% by weight of dry clay were investigated. All tested samples were investigated at three different curing periods: 1, 10, and 28 days. Laboratory investigation included determining pH values, conducting one-dimensional odometer tests, and measuring suction. To achieve a 90% reduction in the swell potential of expansive clays, it was found that Tabuk clay requires at least 2–3% lime addition, while Al-Qatif clay requires 3–4% lime addition. Al-Ghatt clay requires more than 4% to reduce the swelling potential by 90%. These differences are attributed to the mineralogy of the clay and the pozzolonic reactions as a result of adding hydrated lime.