Performance grades, environmental and economic investigations of reclaimed asphalt pavement materials

Abstract

Recent years, due to the advantages of using fewer raw materials, reducing cost and environment protection, the reclaimed asphalt pavement (RAP) has attracted wide attentions. Nowadays, some research studies have been completed to conduct the specifications and guidance for the effective implementation of the hot mix asphalt material. However, after the RAP is utilized in the pavement, the actual performance characteristics to resist the rutting distress at a high temperature and avoid the low temperature crack are not investigated in great detail. In addition, the environmental and economic evaluations of these asphalt materials are not explored very well. This study explored the high and low temperature performance grades as well as energy saving, greenhouse gas (GHG) emission reduction, and cost saving of reclaimed asphalt binders incorporated into the commonly used base binders. Moreover, the results of this study would provide advice and guidance on both economic development policies and environmental protection policies. The experimental designs in this research included three base binders and six RAP sources with respect to the dynamic shear rheometer tests, bending beam rheometer tests and local survey. The results indicated that, at the high temperature, when incorporated 15% and 30% extracted aged binders, one grade (6 °C) and two grades (12 °C) of base binders were generally improved respectively. In addition, the increase of 2–3 °C and 4–5 °C were found at the low temperature when used 15% and 30% aged binders, respectively, regardless of RAP source. Moreover, the reduced energy consumptions, GHG emissions, and costs of the RAP mixtures containing 30% aged binder are generally greater than those with a lower percentage aged binder.