Evaluating polyethylene terephthalate in asphalt concrete with reclaimed asphalt pavement for enhanced performance

Reclaimed asphalt pavement (RAP) is widely utilized as a green base/subbase material. Still, this material can only be used in small amounts in asphalt concrete mixtures. Many studies have shown that a large amount of RAP replacement could make asphalt pavements less effective. The goal of this study is to evaluate the mechanical properties of asphalt concrete made with 100% RAP aggregate and crushed polyethylene terephthalate (PET) bottles. The effect of adding PET to RAP aggregate was investigated with PET contents ranging from 0% to 1.0% by weight of RAP aggregate. The improved static and dynamic performances of the RAP asphalt concrete were assessed via the Marshall stability, the strength index (SI), the indirect tensile strength (ITS), the indirect tensile fatigue (ITF), the indirect tensile resilient modulus (ITMR), and the resistance to rutting tests. The optimum PET content of 0.6% provided the best performance across all experimental testing, resulting in a 25% improvement in Marshall stability, 19% in SI, 69% in ITS, 11% in ITMR, 270% in ITF, and 80% in rutting resistance compared to 0% PET content. Furthermore, it has been determined that an increase in ITS results in a corresponding increase in ITMR, exhibiting a linear correlation. After carefully analyzing the cyclic test data, a model for fatigue distress was suggested. This study's results will aid in developing sustainable pavement options, including RAP and PET, from both an economic and environmental standpoint.