Fatigue-fracture relation on asphalt concrete mixtures

The purpose of this study is to examine potential relationships between fatigue and fracture parameters obtained from standardized laboratory tests. A flexural bending beam test was used to obtain two fatigue parameters, which include a traditional fatigue criterion based on stress or strain to find number of cycles to failure and a new fatigue criterion based on an energy approach known as the plateau value (PV). Similarly, a disk-shaped compact tension DC(T) fracture test was used to obtain fracture energy parameters, including: fracture strength, pre-peak fracture energy, post-peak fracture energy, and total fracture energy. A factorial of the eight possible correlations was computed to determine the strongest association between the fatigue and fracture parameters for the asphalt mixtures investigated. The study was motivated by the desire to investigate the feasibility of predicting time-consuming fatigue test results with fracture test results, which can be obtained much more rapidly. Based on the results obtained in this study, it was shown that a potentially strong correlation exists between fatigue and fracture mechanisms in asphalt concrete, as characterized by parameters associated with dissipated or consumed energy. As presented through the statistical analysis, the plateau value (PV) and the pre-peak fracture energy (Gf-pre) are the most highly correlated parameters from the fatigue and fracture tests, respectively. This study is based upon limited experimental data and is explored an initial starting point to find relationships between fatigue and fracture mechanisms. Much more experimented and analytical work will be needed to fully understand these relationships and to develop a standardized interconversion scheme