The Karal Soil from North Cameroon: A Swelling Soil Stabilized with a Mixed Cement/Hydrated Lime Treatment

The swelling clay-rich soils, known as karal soils in Cameroon, cover a large area in the North of the country. Such soils used in earthwork for road construction are at the origin of damages to structures whose durability is drastically shortened. Based on the usual soil treatment for road construction, the present study demonstrated the ability of a mixed treatment with a hydraulic binder (CEMII) and hydrated lime (HL) to decrease the swelling phenomenon and improve the mechanical performance of karal soils. Hydrated lime was imposed by the near non-existence of quick lime (QL) in Cameroon. It made the originality of the applied treatment that usually rarely combines CEMII and HL. To test the durability of the formulated soil treatments with various additives contents, long or short cycles of wetting-drying was imposed, and the volume variation until the total disaggregation of soils was followed. Tests confirmed the possible use of a CEMII/HL mixture to prevent soil from damages caused by the swelling-shrinkage phenomenon.