An asphalt concrete has been modified by adding four polymeric wastes: polyethylene (PE) from micronized containers, polypropylene (PP) from ground caps, polystyrene (PS) from hangers and rubber from end-of-life tyres (ELT). These polymeric wastes were selected according to their availability, homogeneity and economic criteria considering the big amount of material required to build a road.\ud The dry method has been used to modify the bituminous mixture due to its simplicity and the possibility to be carried out in any asphalt plant without important modifications. This is very important in order to spread the process and recycle the polymeric waste in the same place where it is produced, hence improving the environmental impact.\ud The reference asphalt mixture and the four modified asphalt concretes have been analysed separately and their performance compared, evaluating their resistance against plastic deformation, stiffness, fatigue resistance and workability. The Master curve and the Black diagram of the mixtures were also calculated.\ud The results showed that the use of polymeric wastes significantly increased the stiffness of the reference mixture in all cases, but especially when PE, PP and ELT were used. However, none of these materials significantly modifies the fatigue behaviour of the reference mixture. Regarding the resistance against plastic deformation, the use of both PE and ELT led to an increase of the resistance, whereas PP did not modify it and PS decreased it. As for workability, the energy of compaction of the modified mixtures did not suffer any important change. Therefore, according to the results obtained, PE, PP and ELT can be used to modify asphalt mixtures since they improve or do not change their properties. On the other hand, PS should be further studied because of the contradictory results obtained, and only when plastic deformation is not a problem this material could be used.POLYMIX is a project financed by the “LIFE+” program of the European Union, with reference number LIFE10 ENV ES 516. This project was carried out by a consortium coordinated by GITECO (Construction Technology Applied Research Group, University of Cantabria) and integrated by ACCIONA Infrastructures, AIMPLAS (Research Association of Plastic Materials), and VIA-M (Department of Road Construction from the Madrid Regional Government).\ud The authors wish to acknowledge and especially thank Belén Monje and Eva Verdejo (AIMPLAS) and Raquel Casado and Elena Sáez (ACCIONA) for their collaboration

The durability and maintenance of pavements depend on several factors. One of the most influential is the bond between layers. This bond is responsible for ensuring all layers behave as a single entity, reducing cracks and deformation of the pavement. Several methods, developed by different authors over the past 30 years, to measure bonding between layers are analyzed in this paper. Different research lines are discussed, concluding that the most influential variables are: tack coat type, dosage, mixture type, surface characteristics, temperature, and emulsion breaking time. In order to reach the highest bond strength values, the following factors should be considered: high values of surface macro-texture, low temperatures, the use of heat-adhesive emulsion, a dosage from 300 to 450 g/m2 of residual bitumen and the compaction after emulsion break. Moreover, a non-destructive test method to assess tack coat dosage on site is proposed