Effect of laboratory aging on moisture susceptibility of polymer-modified bituminous mixtures

The increase in heavy traffic load due to increasing number of vehicles and trucks with the effects of other exterior factors such air temperatures and moisture have caused distresses on pavement. In this study, the influence of laboratory aging on the mechanical properties of Polyethylene-modified concrete mixtures was studied utilizing different experiments. Polyethylene Terephthalate (PET) waste plastic bottles was used at different percentage i.e. 1%, 2%, 3%, and 5% by weight of bitumen. The design bitumen content was obtained for dense mixture according to superpave system. Marshall Stability, Flow, indirect tensile strength, and tensile strength ratio at two aging levels are conducted to evaluate the performance change of asphalt mixtures. Mixtures were conditioned at short-term aging temperature of 135 degrees C for different time periods (2, 6 and 8 hrs). Long-term aging was completed after compaction of test specimens to the desired air void level of 4 +/- 0.5% using Superpave gyratory compactor at three different temperatures (75, 85 and 95) degrees C and four aging periods (0, 2, 5, and 10 days. The results showed that adding PET polymer to paving blend has good significance; it improved stability, flow, HMA density in addition to moisture resistance because of great elastic ability provided by PET particles, it can be found that 4 and 5% of PET content gave the best results as compared with the control mixture.