Influence of Plastic Waste on the Workability and Mechanical Behaviour of Asphalt Concrete

The use of plastic waste as a bitumen extender added throughout the manufacturing process of asphalt concrete contributes value to that type of waste. Moreover, this type of polymer can improve some mechanical properties of asphalt concrete without weakening its workability and other mechanical characteristics too much. The study aimed to address these issues for four types of plastic waste, using different plastic contents added by the dry process and compared the results with a conventional mixture without plastic. A set of laboratory tests, such as volumetric parameter evaluation, the Marshall, gyratory compactor, and indirect tensile tests, repetitive four-point bending; and repetitive compression, assessed the workability and mechanical behavior of the studied materials. The results show that, although the addition of plastic waste reduces workability, the asphalt concrete retains satisfactory handling conditions. By adding plastic waste, the asphalt concrete becomes more elastic, and the stiffness values of the material are adequate to apply the material in a pavement surface layer. The resistance to fatigue cracking was at a suitable level for the asphalt mixtures studied. Adding the plastic waste in the study generally improved resistance to permanent deformation, although the performance was plastic type and content dependent.