Evaluation of effectiveness of geotextile in reducing subgrade migration in rigid pavement

Pumping in rigid pavements is defined as the migration of subgrade soil into the overlying layers, redistribution of materials under the slabs, and ejection of materials through joints. Pumping can compromise pavement performance. This study evaluated geotextiles as separation and filtration solutions to mitigate pumping and reduce the resulting pavement joint faulting. A one-third scale Model Mobile Load Simulator (MMLS3) was used to simulate cyclic loading on a scaled rigid highway pavement that has experienced some loss of load transfer. The results from four tests were compared to assess the effectiveness of geotextile in reducing pumping. The four experiments had identical configurations, except that a geotextile was placed at the subgrade-subbase interface in two tests. Non-plastic saturated silt and partially saturated aggregate were used as the subgrade and subbase, respectively. Using a geotextile at the subgrade-subbase interface substantially reduced pumping. More fines accumulated in the subbase beneath the approach slab than the leave slab, which resulted in faulting of the slabs. However, the magnitude of this faulting was more pronounced for the cases without geotextile. Reductions of 71% and 52% occurred in the magnitude of subgrade migration and faulting, respectively, when using geotextile. To conclude, geotextile can be effective in mitigating pumping, leading to longer-lasting pavement systems.