Long-term performance of recycled asphalt mixtures containing high rap and reclaimed asphalt shingles

The application of reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS) on asphalt pavement can reduce the asphalt paving cost, conserve energy and protect the environment. However, the use of high contents of RAP and RAS in asphalt pavement may lead to durability issues, especially the fatigue cracking and thermal cracking. It is necessary to conduct a series of analyses on asphalt mixtures containing high RAP and RAS, and seek methods to enhance their long-term performance. This paper provides a comprehensive over-view of the long-term performance of recycled asphalt mixtures containing high contents of RAP and RAS. The findings in this research show that rutting resistance of high recycled asphalt mixtures is not a concern, whereas their resistance to fatigue and thermal cracking is not conclusive. Recycling agents can be used to improve the thermal cracking resistance of high recycled asphalt mixtures. An optimum decision on recycling agents will improve the durability properties of high recycled asphalt mixtures. It is recommended that to use a balanced mixture design approach with testing of the blended asphalt binders will provide better understanding of long-term performance of recycled asphalt mixtures containing high RAP and RAS.