Assessment of the Use of Hot-Mix Recycled Asphalt Concrete in Plant

Hot-mix recycled asphalt concrete in plant is one of the available techniques to perform cost and environmental effective pavement recycling. It is not commonly used in Portuguese paving practice basically because there is a lack of confidence at the end of the production chain. A study was conducted using mixtures from four trial sections, one with a traditional mixture for reference and three with 20, 30, and 40% of reclaimed asphalt concrete from a flexible pavement. The mix production was made in a batch plant without heating the reclaimed material. The laboratory process produced the same kinds of mixtures for comparison. Laboratory tests aimed to establish some fundamental properties for both the trial sections and laboratory mixtures: stiffness modulus, resistance to fatigue, and permanent deformation behavior. This paper contains the comparative results and indicates some useful directives for the use of such materials. It can be stated that for all the analyzed recycled mixtures the level of confidence should be similar to the one offered by the asphalt concrete produced from virgin materials.