Effect of polypropylene fiber-reinforcement on the mechanical behavior of silty clay

Closure requirements for landfills typically require the construction of a cover barrier which includes a compacted silty clay liner essential to safety on site. However, this barrier encounters numerous problems, especially those related to the differential settlement, which may cause stress in the clay layer leading to the development of cracks. Tensile stress damage and shearing are observed on the cap cover. Due to the weak mechanical performance of the clay layer it was proposed to add polypropylene fiber-reinforcement. Direct tensile tests and compression tests under confinement were carried out on unreinforced and reinforced clayey soil. An improvement in soil resistance and in the brittleness index of fiber-reinforced clay was characterized. It was shown that, in compression, the composite material becomes more and more rigid. On the contrary, under direct tensile tests the reinforced clay exhibits a benefit in ductility which can mitigate potential cracking. The proposed solution, technically feasible, enabled an improvement of the mineral barrier.