Multiscale Assessment of Low-Temperature Performance of Flexible Pavements

Abstract

AbstractThe increase of heavy-load traffic within Europe requires the development of appropriate tools for the assessment of existing and new road infrastructure. In this paper, such a tool is presented, combining multiscale material modeling of asphalt with structural analysis of flexible pavements representing plate-like structures at low temperatures. At this temperature regime, rapid cooling of the road surface in consequence of temperature drops may result in so-called top-down cracking. These cracks, when propagating further into the base layer, significantly reduce the service life of road infrastructure. Within the proposed multiscale model for asphalt, the temperature-dependent viscoelastic properties of asphalt are related to the constituent bitumen, exhibiting the thermorheological behavior, accounting for• the large variability of asphalt mixtures, resulting from different mix design, different constituents (e.g. bitumen, filler, aggregate), and the allowance of additives, and• changing material behavior in consequence of thermal, chemical, and mechanical loading.The parameters of the employed viscoelastic material model for asphalt are obtained from upscaling of parameters identified at the bitumen-scale up towards the macro-scale i.e., the scale of structural analysis, with the viscoelastic behavior of bitumen serving as input. Upscaling is performed in the framework of continuum micromechanics using the elastic-viscoelastic correspondence principle. The presented multiscale model is applied to asphalts typically used for surface and base layers of flexible pavements. The so-obtained macroscopic model parameters are employed in the numerical analysis of flexible pavements, giving access to stresses resulting from (i) a sudden drop of the surface temperature in consequence of changing weather conditions and (ii) traffic loading. Comparison of the so-obtained surface stresses with the tensile strength of asphalt at the respective surface temperature allows an assessment of the risk of top-down cracking in flexible pavements.Keywordsbitumenasphaltpavementviscoelasticitymultiscale modelupscalingidentificationvalidationfinite element method