Application des méthodes d'empilement granulaire à la formulation des Stones Matrix Asphalts (SMA)

In Quebec, temperature deviations from one season to the next create harsh conditions for asphalt mixes, which must retain enough deformability at low temperature to limit the risks of thermal cracking, while maintaining adequate cohesion at high temperature to minimize rutting. Stone Matrix Asphalt (SMA) has been designed to meet these needs thanks to a unique granular skeleton associated with a modified bitumen. Even though a number of mix design methods have already been adapted to SMA material applications, they still do not allow reconciling the fact of generating a stone-to-stone contact while optimizing compaction capability. The magnitude of the intermediate fraction in SMA mix design will be showcased herein. By applying the concepts associated with granular combinations, a design methodology for this mix category has been developed; it will be demonstrated that SMA mixes can be derived by substantially reducing bitumen content. The initial set of results from laboratory testing suggests a potential savings of nearly 15% bitumen. Moreover, the proposed approach enables reaching SMA mix compaction more quickly.