Performance characteristic evaluation of asphalt mixes with plastic coated aggregates

Abstract

Construction and maintenance of a large number of road networks result in degradation of environment and depletion of natural resources chiefly: raw materials. As a mitigation strategy, sustainable and smart pavement technologies were developed and practiced with a view to balancing the performance criterion and need for utilization of waste materials. In this connection, the use of plastic waste in pavement construction has gained popularity. Despite the numerous studies available in the literature that evaluated the different performances of plastic modified asphalt mixtures, the effect of different levels of plastic inclusion and its associated performance improvement is a major research interest. Thus, the objective of the study was to utilize waste plastic in asphalt pavement construction and evaluate the effect of different levels of plastic inclusion. In this study, shredded waste plastics were added into mix starting from 2% by weight of asphalt binder to 12% with a successive increment of 2% through dry mix process. Different aggregate tests were performed to observe the effect of aggregate coating with plastic. After that, the Marshall test, retained stability, dry–wet and freeze–thaw indirect tensile strength tests were conducted upon modified and control asphalt mixes. Experimental results indicated that the physical properties of aggregate improved with the increment of the plastic content. It was possibly due to the improvement in adhesion between the aggregates with the presence of plastic. Also, ITS (dry, wet and freeze–thaw) increased due to plastic modification of mix. Further, an improvement in stability was observed due to plastic modification of mix. Thus, it can be also observed that the strength of the bond between the aggregate and the binder enhanced with the addition of plastic to the mix. Overall, it can be concluded that utilization of road plastic not only improved the environmental sustainability but also enhanced the pavement performance.