Development of a test method for investigating the fatigue behavior of asphalt pavements on a half-scale



Photo of Julian Kohlmeier © Copyright: ISAC


Julian Kohlmeier

Head of Testing Facility


+49 241 80-25222



Problem Definition

When designing asphalt roads, the aim is to dimension the bound and unbound layers of road pavements sufficiently thick to withstand traffic loads for several decades. However, as the layer thickness increases, so do the resource requirements of the road and, consequently, the construction costs. This conflict is exacerbated by the fact that, on the one hand, the traffic load on German roads continues to increase and more durable roads are needed, while, on the other hand, the essential raw material resources for asphalt as a construction material (aggregate and bitumen) are becoming scarce. New roads must therefore be dimensioned in such a way that the desired service life is achieved without using more resources than are absolutely necessary.

In order to achieve economical and at the same time resource-saving dimensioning of the superstructure, more and more roads are currently being dimensioned analytically. The RDO Asphalt 09 is used for this purpose. The RDO Asphalt 09 requires material parameters as input, including the fatigue behavior of the asphalt used.

To test the fatigue behavior of a real asphalt road, very large and often site-bound test rigs are occasionally operated. Due to the high testing costs, the high testing effort and, for some of the tests, the limited predictive power of the existing test methods, safeguarding fatigue tests on a larger scale are not performed in most cases.

Project Objectives

  • Development of a mobile test rig on a half scale
  • Simulation of the fatigue behavior of asphalt roads over a period of 10 years within 1-2 weeks on a half-scale in a realistic and cost-effective manner
  • Upscaling of the half-scale to the full-scale using FEM simulation
  • Use of the digital FEM simulation to derive the remaining service life of the road under investigation


  • Development of a mobile test rig in compact half scale, which applies a rolling load circularly
  • Creation of a kinematic multi-body model of the test rig
  • Modification of existing visco-elastic asphalt models based on the Navier-Cauchy equation
  • Coupling of the asphalt model with the multibody model of the test rig
  • Development of a prediction method for the load-dependent service life of asphalt roads