Behavior of Flexible Pavements on Expansive Soils

This investigation discusses the findings on analysis results of a pavement structure constructed on a relatively expansivematerial consisting mainly of brown clayey silt in Tebessa, Algeria. Cores were taken to laboratory from apiece of roadwork. Remolded samples were taken from subgrade of a deteriorated road. The soils were generallyfound to be of medium plasticity and of a medium to high expansion potential. Oedometer test for free swell indicateda constant volume pressure that produced stress in excess of 350 kN/m2. The following involves description of thebehavioral characteristics of expansive soil as it relates to flexible pavements. Computer code Plaxis 8.2 was used fornumerical simulation to check the behavior of structure pavement with three models in pavement structure, and freeexpansion test was performed to calibrate the soil subgrade with Soft-Soil Model. The results showed that the combinedmodel Mohr-Coulomb in the pavement structure and the Soft-Soil in subgrade accord perfectly with deformationstaken on the existing pavement. To stabilize the swelling character of subgrade, an adequate surcharge pressureis used according to the procedure described in the paper. It showed that after 9 months, the deformations have beenstabilized at -0.007 m without any cracks in the pavement.

Keywords:

Flexible pavements , expansive subgrades , soil calibration , Oedometer test , soil behavior , finite elementmethod