Reclaimed asphalt pavement and additives’ influence on 3D linear behaviour of warm mix asphalts

This paper presents results of laboratory tests on nine types of specimens consisting of different hot and warm mix asphalts produced with a reclaimed asphalt pavement. Linear viscoelastic behaviour was investigated using tension–compression tests on cylindrical specimens on a wide range of temperatures (from −25°C to +45°C) and frequencies (from 0.03 to 10 Hz). Complex moduli, E*, and complex Poisson's ratios, ν*, were determined in two perpendicular material directions. Differences between measured ν* reveal a negligible anisotropy in the horizontal confection plane. The time–temperature superposition principle was verified with good approximation, with the same shift factor values, in one-dimensional and three-dimensional conditions. The same values of shift factor were also obtained for all specimens that contain bitumen with identical crude oil origin. Experimental results were modelled using the 2S2P1D model previously developed at the University of Lyon/ENTPE. In this paper, a new representation of results using normalised curves is proposed. These curves show identical properties for the different materials, which have the same origin of bitumen and aggregate. Finally, the performance of tested materials was compared.