Corrosion behaviour of steel in sustainable concrete made with recycled asphalt pavement aggregates (RAP)

The implementation of sustainable development in the construction field can be pursued through the use of aggregates alternative to natural ones, including Recycled Asphalt Pavement (RAP) derived from pavement maintenance activities. The need to reduce asphalt waste and the consumption of natural aggregates, along with the compatibility of RAP with traditional aggregates, makes its use for construction sector potentially sustainable, although the effects on the durability of reinforced concrete structures have not yet been fully explored. As part of the RAPCON project, funded by Fondazione Cariplo, an experimental study was carried out by taking into account various types of reinforcement in contact with concretes differing on percentage of RAP, type of cement and water/cement ratio. This paper discusses the capacity protection of concretes with RAP on embedded carbon steel. The results of experimental tests carried out to evaluate the resistance of concretes to carbonation (under accelerated exposure conditions) were also discussed. In addition, the study investigates the corrosion behavior of the embedded reinforcing bars in such concretes once carbonated. The note highlights the importance of properly designing RAP mixes to achieve durable reinforced concrete structures by taking into account the aggressive environmental conditions.