Open-graded asphalt mixes are often used for wearing surfaces of roads exposed to large amounts of rainfall throughout the year. The high permeability of the mix guarantees fast drainage of the water away from the surface and thus increases road safety. However, the large amounts of water that flow through the asphalt have a negative effect on the material characteristics of the mastic and cause debonding of the aggregates from the mastic, called raveling. To understand and quantify the physical processes and the mechanics leading to raveling, an extensive experimental and analytical investigation is being undertaken at Delft University of Technology in the Netherlands. One goal of the investigation is the development of the finite element tool RoAM (raveling of asphalt mixes), which is capable of simulating the gradual development of damage throughout asphalt mixes due to water infiltration. Desorption, diffusion, and dispersion are included as fundamental processes. This paper shows the results of a computational analysis to identify the impact of the different water damage phenomena and presents results of a sensitivity study of the relevant parameters. From the computational analyses it is concluded that simulation of water damage in asphaltic mixes is possible if the desorption characteristics as well as the diffusion and dispersion coefficients can be determined.
Abstract