Behavior of Flexible Pavements on Expansive Soils

This investigation discusses the findings on analysis results of a pavement structure constructed on a relatively expansive material consisting mainly of brown clayey silt in Tebessa, Algeria. Cores were taken to the laboratory from a piece of roadwork. Remolded samples were taken from subgrade of a deteriorated road. The soils were generally found to be of medium plasticity and of a medium to high expansion potential. Oedometer test for free swell indicated a constant volume pressure that produced stress in excess of 350 kN/m2. The following involves describing the behavioral characteristics of expansive soil as it relates to flexible pavements. Computer code Plaxis 8.2 was used for numerical simulation to check the behavior of structure pavement with three models in pavement structure, and free expansion test was performed to calibrate the soil subgrade with Soft-Soil model. The results showed that the combined model Mohr-Coulomb in the pavement structure and the Soft-Soil in subgrade accord perfectly with deformations taken on the existing pavement. To stabilize the swelling character of subgrade, an adequate surcharge pressure is used according to the procedure described in paper. It showed that after nine months, the deformations have been stabilized at -0.007 m without any cracks in the pavement.