Thermomechanical behaviour of bituminous materials including RAP and rejuvenator and environmental impact of their fabrication process

Abstract

Recycling, RAP material, rejuvenator, estimation, prediction, environment. Abstract: The study presented in this thesis has been carried out within a collaboration between Politehnica University Timisoara/Faculty of Civil Engineering/Department of Overland Communication Ways, Foundations and Cadastral Survey from Romania and Université de Lyon/École Nationale des Travaux Publics de l'État (ENTPE), laboratoire de Tribologie et Dynamique des Systèmes (LTDS) from France. The objectives are, i) the characterization of the thermomechanical performances of binder blends and bituminous mixtures produced with Reclaimed Asphalt Pavement (RAP) and rejuvenator (Rej) and, ii) the investigation of the potential environmental impact related to the production of a mixture containing different amounts of RAP material and Rejuvenator. Therefore, comprehensive experimental investigations were performed on binders and mixtures. All tests on binders and mixtures were performed in the Road Laboratory from Politehnica University Timisoara, together with the environmental impact assessment. On the other hand, the analyses, estimations and predictions of most parameters/characteristics of binders and mixtures were performed at ENTPE. The study on binders focused on the investigation of the influence of a RAP extracted binder and the rejuvenator on the properties of different binder blends produced by mixing one type of fresh binder, a straight run 50/70 pen. grade binder, a RAP-extracted binder and a rejuvenator of vegetal origin. The experimental plan includes a total of 17 binders. A new method is proposed to estimate the conventional properties, the LVE properties, the steady shear viscosity and critical temperatures. Stronger correspondence, proved by the statistical analysis, was found between the estimated values of all abovementioned parameters obtained with the proposed method compared to the classical method, and experimental values. The study on mixtures focused on the investigation of the effects of the RAP material and the rejuvenator on the thermo-mechanical properties of 13 bituminous mixtures produced with different amounts of RAP material and with or without a mix of vegetal origin used as a rejuvenator. One conventional Hot Mix Asphalt was used as a reference. All materials used in this study are specific for Romania. SHStS transformation was applied. A satisfactory prediction was obtained even by using the limited DSR measurements on binders. The Environmental Impact Assessment (EIA) proved that the addition of RAP material leads to a net decrease of the energy use and environmental impact. On the other side, when the rejuvenator is used in this process, it can affect the energy balance and reduce the difference in environmental impact.