Thermomechanical characterization of asphalt mixtures modified with high contents of asphalt shingle modifier (ASM®) and reclaimed asphalt pavement (RAP)

The reuse of reclaimed asphalt pavements (RAP) in asphalt mixes at high substitution rates has become a major economical and environmental necessity. However, this reuse of RAP is technically limited by the impact of RAP on the behavior of the mixes and industrially limited by the incorporation capacity of RAP in plants. On the other hand, several studies and industrial experiences showed that the reuse of manufacturer-waste asphalt roofing shingles as a modifier in asphalt mixes enhances the behavior of the asphalt mixes at different levels (fatigue, rutting and stiffness) without having a negative impact on low-temperature cracking when an appropriate asphalt mix design is used. The objective of this paper is to assess the behavior of asphalt mixes using a combination of RAP and asphalt shingle modifier (ASM®) together at high substitution rates. An experimental program was set up and carried out at the Lafarge Research Center and the French Ecole Nationale des Travaux Publics de l’Etat. A reference mix, and other mixes, modified with different percentages of RAP and ASM® were evaluated. The experimental results showed that the mixes with up to 15 % of RAP and 5 % of RAS behave well compared to the reference mix. Beyond these limits, low-temperature cracking behavior could be altered. Certain technical solutions were then evaluated and are presented in this paper.