Pavement engineering materials: Review on the use of warm-mix asphalt

Warm asphalt mixtures have been used worldwide aiming at saving energy and reducing emissions throughout the production process, without decreasing the in-service performance. This has been achieved with wax additives, chemical additives and foaming techniques. Benefits and drawbacks are mentioned in the literature for each process. This paper is a review of the main aspects involved in WMA technology, including constituent materials, mix design and mechanical performance issues, as well as technological specificities. Some discussion associated to life-cycle analysis is also considered. In the view of the literature review, it can be stated that WMA is a very interesting technology, able to contribute to achieve environmental objectives along with acceptable performance. WMA processes themselves require some additional complexity that must be considered by the players involved.