Simultaneous Use of Rejuvenator and Warm Mix Asphalt Chemical Additive to Produce Sustainable Asphalt Pavements: A Case Study in Portugal

In addition to future raw material scarcity, environmental crises have made scientists and road authorities focus on the sustainability of asphalt pavements more than ever. With this aim, several short-term and long-term techniques and strategies have been set via carbon neutralization plans. Among these strategic plans, both asphalt recycling and Warm Mix Asphalt (WMA) play crucial roles. Each of these techniques are potentially beneficial at different stages of asphalt pavement production and laying. This research represents a case study in Portugal where, for the first time, an asphalt pavement containing 30% of Reclaimed Asphalt Pavement (RAP) was produced as WMA, using a liquid rejuvenator and a mixture temperature lowering chemical product. The produced material was laid in trial sections using traditional construction equipment. The laboratory phases included the mix design, post-production controls, core analysis, and monitoring. The testing plan included conventional volumetric analysis, Marshall stability, tensile strength, stiffness modulus and resistance to rutting parameters, and fatigue endurance tests. When applicable the obtained test results were compared with the technical specifications of two of Portugal’s main roadway authorities. It is noteworthy that, although very high modulus and rutting resistance was recorded, the fatigue performance was better than expected. This could stem from the precise and correct selection of the dosage and the type of the rejuvenator. While some recycling agents i.e., flux oils increase the rutting susceptibility, the used rejuvenator did not impact this crucial structural mechanical parameter.