State of the art review on the principles of compatibility and chemical compatibilizers for recycled plastic-modified asphalt binders

Plastics have become a key material in industrial development in recent decades, primarily due to their low production costs and ease of manufacturing. Despite this, their low biodegradation and ability to absorb harmful toxins make their disposal challenging and unsustainable. Recycling plastic waste as a substitute for expensive polymers in asphalt binder modification offers a potential solution to mitigate environmental impact, reduce costs, and conserve the natural resources typically used in polymer-modified asphalt. Nevertheless, challenges remain, particularly with regard to the compatibility of plastics and asphalt binders. Poor compatibility can lead to issues such as phase separation, reduced rheological properties, and weakened mechanical strength, all of which undermine the performance and durability of the modified asphalt. This review explores the compatibility of polymer-modified asphalt binders, examining key polymer properties affecting compatibility and how compatibility affects morphology, storage stability, and rheological behavior. Also, it highlights key tests to assess compatibility as well as chemical strategies to improve the compatibility of recycled plastics modified asphalt binders.