Towards a use of waste polyethylene in asphalt mixture as a compaction aid

As one of the most common plastic wastes in the world, polyethylene (PE) has been recycled and utilized to improve the performance of asphalt pavement, enabling it to withstand these conditions. Previous studies on the use of waste plastics as part of mix design have shown mixed results. On the other hand, adequate compaction has been essential to asphalt pavement performance and agencies/contractors strive to improve compactability of asphalt mixture. This study investigated the incorporation of waste PE with different sizes into asphalt mixtures in accordance with modified dry process as a compaction aid to facilitate compaction. The results show that the asphalt mixture modified by waste PE improves compactability and reduces the rut depth, with cracking performance being dependent on the size and type of the waste PE. The use of shredded waste PE flakes was observed to enhance the cracking performance of asphalt mixtures at intermediate temperatures, as evidenced by an increased CT-index. This improvement indicates that the use of PE flakes could potentially serve as a promising solution for achieving good compaction of asphalt mixture and thus extending pavement life, as well as enabling large-quantity use of waste plastics.