Mechanical Assessment of Recycled Bituminous Mixtures

Bituminous mixtures have a key attribute that they can be 100% recycled without downgrading its functionality. This represents the highest value application and has significant economic and environmental benefits. Every year billions of euros are spent on road construction and maintenance globally. These operations produce a considerable amount of reclaimed asphalt pavement (RAP), which is a valuable waste. Its re-use reduces the depletion of quality resources in landfilled. RAP recycling is a step forward in the direction of sustainable approaches as defended by the recent policies yearns. RAP incorporation in new bituminous mixtures can be associated with different techniques, rejuvenators and additives. This incorporation represents the first cycle of the material’s life. The circular economy presupposes that materials have several cycles during them life. Therefore, the multi-recycle capacity of the bituminous mixtures needs to be evaluated. The main objective of the paper is to analyze the short- and long- term mechanical capacity of RAP in new bituminous mixtures. For that, a laboratory study involving a surface dense bituminous mixture will be described. One RAP incorporation percentage was evaluated (25%) and to take advantage of the binder properties a commercial vegetable rejuvenator was used. The long-term oven ageing protocol was used to simulate the in-service ageing. The stiffness modulus, resistance to fatigue, water sensitivity and permanent deformation resistance were assessed for different compositions. The study showed that bituminous mixtures have potential to be recycled due to the results obtained even in terms of long-term performance. Test results confirmed that recycled bituminous mixtures had at least an equivalent performance over the primary material.