Use of Polymer/Bamboo Reinforced Rap in Base Course of Flexible Pavement Construction

A set of model tests were carried out in laboratory on Wet Mix Macadam (WMM) and Reclaimed Asphalt Pavement (RAP) without and with reinforcement in this study. WMM material is generally used as base course in flexible pavement and it was used in model tests without any reinforcement. RAP material was obtained as waste material by milling of old bituminous pavement prior to its strengthening and it was used in model tests both without and with reinforcement. WMM/RAP material was laid on soft marine clay layer acting as subgrade for laboratory model testing. Polymer/Bamboo geogrid and geocell were used as reinforcements to RAP. Tensile strength of polymer geogrid and bamboo geogrid was 80 kN/m and 93 kN/m, respectively. Model tests results indicated that the improvement factor on load bearing capacity of polymer (geogrid + geocell) reinforced RAP is 1.75 as compared to that of unreinforced WMM. Similarly, the improvement factor on load bearing capacity of bamboo (geogrid + geocell) reinforced RAP was observed to be 1.24 in comparison to that of unreinforced WMM. The above observations suggest that the reinforced RAP has the potential to be used as base course material of flexible pavement. Cost analysis based on preliminary design showed that the alternative pavement option with polymer/bamboo reinforced RAP as base is cost effective as compared to that of conventional flexible pavement with granular base.