Evaluation of bituminous binders miscibility for warm-mix recycling techniques
Résumé
In the road industry, the current challenge is to produce at lower manufacture temperatures asphalt mixtures incorporating Reclaimed Asphalts (RA). However, the incorporation of cold RA could lead to a non-remobilization of the RA aged binder by the virgin one. A double coating appears, what leads to a binders non-mixture and poorer mechanical properties of asphalt mixtures. The objectives are to develop methods to understand remobilization mechanisms and precisely how the virgin binder comes into contact and diffuses into the RA binder. The temperature influence was investigated. Results show that contact angle measurements and micro X-ray fluorescence have been successfully adapted to the 'bitumen/bitumen' interface and interphase study. The RA temperature governs the remobilization initiation phase and influences the blending zone dimension. Therefore, RA should be heated before their incorporation in order to avoid a non-remobilization and guarantee favorable conditions to obtain homogeneous recycled asphalt mixtures with high mechanical performances.