Three-dimensional characterization of asphalt mixture containing recycled asphalt pavement.

This work presents an investigation of the three-dimensional linear viscoelastic behavior of asphalt mixtures containing different percentages of Recycled Asphalt Pavement (RAP) materials. Cyclic tests in tension-compression were performed on cylindrical samples in strain-controlled mode, measuring the axial and transverse deformations. Complex modulus and complex Poisson’s ratio were measured at seven temperatures ranges from -20°C to +40°C and at six different frequencies from 0.1 to 10Hz. The time temperature superposition principle for both the complex modulus and the complex Poisson’s ratio was verified and the results were fitted with the 2 Springs, 2 Parabolic elements and 1 Dashpot (2S2P1D) model. From the experimental results, it is possible to observe that the complex modulus and the complex Poisson’s ratio increase, while the phase angle of both the complex modulus and the Poisson’s ratio decreases for higher RAP percentages. In addition, the effects of RAP on the parameters of the 2S2P1D model and on the shape of the Cole-Cole plot and Black diagram were evaluated, showing a strong dependence on RAP content.