Performance of reclaimed asphalt pavement mixtures under static and oscillatory loading

The use of recycled materials in asphalt pavement is common practice as it yields economic benefits and reduced exploitation of natural resources. Over recent decades, many agencies in the USA have investigated the effect of adding reclaimed asphalt pavement on the field performance of asphalt mixtures used for pavement applications. In this work, the effect of reclaimed asphalt pavement on the low-temperature properties of hot mix asphalt was investigated using two tests: bending beam rheometer mixture creep, which is based on static loading, and dynamic shear rheometer mixture complex modulus, which uses oscillatory loading. Based on the experimental data, creep stiffness, m-value, thermal stress, critical cracking temperature and complex modulus were calculated, and then statistically and graphically evaluated. The results revealed that, at low temperature, most of the mixtures prepared with reclaimed asphalt pavement had poorer performance than a mixture prepared from virgin materials. However, no significant differences in creep and complex modulus properties were observed beyond a specific reclaimed asphalt pavement content, which is in the range of 25-40% depending on the stiffness of the binder used.