A comparative study between unmodified and modified bituminous mixtures by PET, case study: southwest of Algeria

Large quantities of plastic waste are produced worldwide. These plastics are toxic due to their non-biodegradability and unsightly appearance. Traffic intensity and climatic and environmental conditions limit the performance of bituminous mixtures. There is a risk of permanent deformation at high temperatures and thermal cracking in the presence of moisture. The southern Algerian region has a severe continental climate, where negative temperatures can be recorded during the winter and values ​​exceeding 50°C during the summer. This work aims to evaluate the performance of bituminous concrete used for roadways' surface layer after adding Polyethylene terephthalate (PET) through the dry process. The bitumen used for the control asphalt mix was replaced by PET plastic waste in a proportion of 5%. We, therefore, study and compare asphalt mixes without and with PET waste and test them using the Marshall test, four-point bending test at 50°C, and the retained strength test. The results showed that the addition of PET in the mixture contributes to reducing creep and permanent deformation and improves the modified mixture's stability, strength, and rigidity, as well as excellent behavior in the presence of humidity, which can modify and improve the mechanical performance of bituminous coatings. At the same time, this modification serves as a high-performance and environmental solution to improve our Saharan roads.