Laboratory Evaluation of a Geosynthetic-Reinforced Pavement over Poor Subgrade

Road construction and other infrastructure works have an ever-increasing demand for good quality construction materials. The availability of natural aggregates for such requirements are now becoming scarce due to the prevailing environmental constraints and the related need for socio-economic sustainability. As a result, recycling of used or waste materials has been gaining a dynamic momentum. One of such material is Reclaimed Asphalt Pavement (RAP) material obtained from the surface course of flexible (bituminous) pavements once the design life of pavement has exhausted. Though RAP material has got usage as partial replacement to the fresh bituminous mix, their performance as a fill material for the base layer of pavement is presented in this paper. To enhance the performance of RAP-filled base layers, it has been reinforced with different geosynthetic materials (geogrid, geocell) and their combination (geogrid plus geocell). For the need of clear distinction among the performance of different reinforcement cases, RAP-filled base layer was essentially prepared upon weak subgrade having low CBR value (black cotton soil). All studies were performed on laboratory-scale pavement model constructed inside an indigenously developed equipment named “Repeated Load Applicator for Pavement Performance”. The RAP-filled base layer when reinforced with geocell and geogrid in single combination was found to perform better than the geocell confinement followed by the geogrid reinforcement. The performance of different reinforcement cases in comparison to the unreinforced case were evaluated in terms of Traffic Benefit Ratio (TBR) and Rut Depth Reduction factors (RDRF).