Dynamic testing of asphalt mixes

Abstract

In the presented research, conventional cyclic tension–compression complex modulus tests and dynamic tests were performed on an asphalt mix (AM) specimen. For the tension–compression tests, the complex modulus was calculated from the measurements of the axial strain and axial stress. For the dynamic tests, an automated impact hammer equipped with a load cell and an accelerometer were used to determine the frequency response functions (FRFs) at five different temperatures. A back-analysis using finite element method (FEM) calculations and a very simple modelling of the material behaviour was proposed to determine the complex modulus of the specimen at each tested temperature. Complex modulus results from dynamic and cyclic tests were compared and are in good agreement. The norm of the complex modulus obtained from dynamic test is slightly higher and no significant difference is seen for the phase angle. Part of the differences observed may be explained by the nonlinearity of AM (strain amplitude is about 500 times smaller for dynamic tests).