Adoption of Statistical Analysis to Evaluate the Permanent Deformation of Polyethylene Terephthalate (PET) Modified Asphalt Mixtures

Permanent deformation (rutting) is one of the most common distress modes in flexible pavement. Rutting performance of asphalt mixture is very susceptible to environmental and loading conditions. In this paper, effects of applied stress and temperature on the permanent deformation of unmodified and Polyethylene Terephthalate (PET) modified asphalt mixtures (0%, 0.5% and 1% of PET by weight of aggregate particles) were evaluated using dynamic creep test at different temperatures (10˚C, 25˚C and 40˚C) and stress levels (200 kPa, 300 kPa and 400 kPa). Response Surface Methodology (RSM) was used to analyze the experimental results. A quadratic model was successfully fitted to the experimental data. According to the results achieved in this study, PET-modified mixtures showed to have higher rutting resistance than the unmodified mixture. Additionally, temperature variation and stress levels played important roles on rutting performance of both unmodified and PET-modified asphalt mixtures.