Experimental Study on Modification of Bitumen Using Waste Plastic for Flexible Pavement

Abstract

The growth in varies type of industries together with population growth has resulted in enormous increase in production of varies type of waste plastic material and it is one of the major environmental concerns. On the other side, the road traffic and the traffic intensity is increasing; the load bearing capacities of the road should be improved. To deal with the problem, study on use of plastic waste as partial replacement to bitumen is considered in the present work. This paper will help to take care of both those aspects. The main objective of this study was to evaluate laboratory performance of modified bitumen mix using waste plastic for flexible pavement to enhance asphalt mix properties. This research has determine the best method of adding polymer in asphalt mix. In this study four proportion (6,9,12 &15%) of waste plastic ( PET and HDPE) were introduced in the asphalt mixture with a selected aggregate grading. Marshal mix design procedure was used, first to determine the Optimum Bitumen Content (OBC) and the OBC was 5.1% by weight of asphalt mix. Number of laboratory tests such as penetration, ductility, softening point, loss on heat and marshal stability test has been carried out by replacing some parts of the bitumen with plastic waste. The results show that there is an improvement on those properties when compared to normal bitumen. The Marshal stability results reveals that the waste plastic (PET and HDPE) increases the stability values of the compacted mixes with increasing the waste plastic content in the bitumen up to 9% PET and 12% HDPE. The density of the compacted mixes slightly decreases with the increase of waste plastic contents in the bitumen. It is expected that using the output of this research, provide an economical solution and minimize the frequency of rehabilitation work by improving the performance of asphalt. It is also expected to substantially reduce volume of environmentally hazardous plastic and environmental pollution. Study recommends contractors and local authorities to confirm using waste plastic in asphalt mix with the proposed percentage (7% PET and 8% HDPE by OBC weight) to improved the performance of asphalt mix. Moreover, further studies are needed in various topics related to effective utilization and best incorporation techniques of waste materials.