Re-use in road construction of a Karal-type clay-rich soil from North Cameroon after a lime/cement mixed treatment using two different limes

Swelling clays characterized by their shrinkage and swelling phenomenon are known to be the main cause of cracking of paved roads. So, the road construction on swelling soils require knowledge and specific techniques, including the chemical stabilization with lime or cement addition. This technique favors the sustainable development by avoiding waste production especially soils. Indeed a maximum reuse of materials located in the building project area allows reaching the "zero loan, zero deposit" objective. In this paper, the efficiency of mixed treatment with lime and cement was tested on swelling karal-type soils collected at Pitoa in the North Cameroon region. The soil samples were characterized by applying microstructural and geotechnical tests (XRD, SEM, Particle Size Analysis, Atterberg Limits, Modified Proctor, CBR test, and Unconfined Compressive Strength (UCS)). The results showed that the mixed treatment of karal soils using a 2% of hydrated lime mixed with CaO or a 3% of low carbonated hydrated lime and 3, 5 or 7% of cement, reduced drastically the soil volume variation under water content change and improved the soil physico-mechanical properties. Finally, soils after treatment reached the minimum characteristics required for recovery in road construction.