Novel Modified Recycled Mastic for Demanding and Sustainable Asphalt Mixtures

New recycled mastic asphalt is been under development, highly modified, for use in asphalt mixture with a strong effect in its properties related with pavement performance. That mastic incorporates different products (among which are industrial by-products) that enhance/improve mechanical performance of the asphalt mixture, namely by: increasing the binder/aggregate affinity; reducing new added binder’ oxidation; increasing binder’ cohesion (ductility strength); improving permanent deformation resistance and increasing fatigue life. At the same time, it reduces the consumption of new added binder (up to 3% less than the usual 5–6%) and does not require the addition of any filler or fine aggregates (#  0/2 mm). Finally, the new mastic asphalt reduces the temperature required during compaction of asphalt mixture and offers a contribution to the circular economy framework, not reducing its mechanical performance and almost without increasing the final construction cost.