Use of Foamed Asphalt and Foamed Bitumen for Recycled Asphalt Mixtures: A Review

The recycling of both worn-out asphalt layers and the entire pavement has led to the development of innovative materials that can be incorporated into conventional asphalt mixtures. Within this type of compounds, foamed asphalt and foamed bitumen stand out, not only from the functional aspect, but also from the environmental aspect, since they allow controlling and significantly reducing the placement temperature of the asphalt mix. In this context, this article develops an exhaustive review of the main aspects of the use of foamed asphalt and foamed bitumen for recycled asphalt mix, taking into account the selection of 86 articles referring to the topic, available in the Scopus, Science Direct, Scielo and Google Scholar databases corresponding to the period 1900 to 2022. It was possible to learn about the application of foamed asphalt and foamed bitumen, its characteristics and properties, its incorporation processes in the mixture, its advantages and disadvantages, its reactions with the different aggregates and their performances in the recovered asphalt mix. Finally, it is concluded that both foamed asphalt and foamed bitumen are highly advantageous due to their properties in recycled asphalt mix, since in addition to greatly reducing the temperature of a conventional mixture, it allows maintaining the same mechanical properties compared to a hot mix asphalt.