Influence of Air Void Content and Loading Frequency on Fatigue Test Results of Bituminous Mixtures

Abstract

This paper focuses on the influence of air void content and loading frequency on the fatigue resistance properties of bituminous mixtures. Fatigue tension–compression tests were carried out on cylindrical samples of three different mixtures. The analysis considers two approaches for defining fatigue resistance. The first, and commonly used, expresses the fatigue resistance in terms of the parameter ε6, defined as the strain level to achieve the failure after a million loading cycles. The second approach is based on a characteristic value of the material damage at the failure. This value considers only the damage due to the fatigue phenomena, and it is considered as an intrinsic characteristic of the material. This approach was developed at the ENTPE/University of Lyon. The energy dissipation of the samples during the tests is also analyzed. From a conventional analysis approach, tension–compression fatigue test results were found to be dependent on void content and on loading frequency. However, the characteristic corrected damage value at the failure of the materials was found to be independent of such parameters.