Performance evaluation of modified moisture barrier in mitigating expansive soil associated pavement distresses

Pavements in many parts of Texas seek frequent maintenance owing to the distress caused by cyclic swelling and shrinking of underlying highly expansive subgrade soil. Research indicates that rainwater intrusion from the edge and cracks on pavement surface is the major cause of such swelling and shrinkage. In this study, an attempt was made to stabilize a pavement section constructed over highly expansive subgrade soil in Frost, Texas using combination of geosynthetic materials referred to as modified moisture barrier. The pavement section exhibited huge cracks along the centerline due to high swell-shrink potential of underlying expansive subgrade soil and needed immediate repair work. Ground penetrating radar and pavement coring along with soil sampling were conducted to assess the site condition. Modified moisture barrier consisting of geocomposite, and geomembrane layers was installed along the compromised section of pavement at the base-subgrade interface to prevent potential moisture intrusion and drain excess moisture away from the pavement system. Moisture sensors and inclinometers were installed in the barrier and control section to evaluate the performance of pavement. Based on initial data, 89% reduction in deformation was observed in the barrier section as compared to the control section.