Development of a design catalog for bonded concrete overlays in the regional road network

Abstract

This paper describes the development of a design catalog for the design of bonded concrete overlays (whitetopping) for existing asphalt roads in the regional road network of Austria. For the underlying calculations of stresses and strains due to traffic loads, different finite-element models with multiple layers were used. Thereby, a large variety of important input parameters were taken into account, such as the condition of the existing pavement, described by its residual bearing capacity. The influence of different climatic conditions over the course of a year to the material properties of the pavement-layers (Young’s moduli) and the bonding properties between the existing asphalt and the new concrete layer were also considered. The calculation of stresses due to temperatur loads (curling stresses) were estimated by using the revised Eisenmann’s model [1]. Based on the determined stresses in the concrete layer due to traffic and temperature loads, a new performance-based design method was used for the implementation of a proper failure criterion and the calculation of the technical service life of the modelled whitetopping pavements. In a further step, the required layer thicknesses of the concrete overlay were determined, depending on the length and the width of the concrete slabs as well as the residual bearing capacity and the remaining thickness of the existing asphalt layers. This allowed the development of different proposed designs for whitetopping-pavements, each with defined layer thicknesses, which were finally summarized into a design catalog. The development of this design catalog and the usage of the proposed pavements will enable a simple but realistic design of whitetopping-overlays on existing asphalt pavements.