EFFECT OF THE FAILURE CRITERION ON THE LABORATORY FATIGUE RESPONSE PREDICTION OF HOT MIX ASPHALT MIXTURES

The primary objective of this research was to determine the effect of the failure criterion used to compute the laboratory fatigue response of hot mix asphalt (HMA) mixtures specified by the Institute of Urban Development of Bogotá D.C. (i.e., md10 and md20 mixtures). The fatigue equations (i.e., fatigue curves) were determined using the controlled-strain trapezoidal fatigue test. The criteria used to establish the fatigue life corresponded to the classic (50% of the initial load)-, damage-, and breakage-failure criterion. Corresponding results suggested that the failure criterion selection can lead to significant differences in the laboratory fatigue life prediction (i.e., fatigue curves). Specifically, for the dense-graded md10 mixtures the fatigue curve was similar disregarding the failure criteria applied. However, for the dense-graded md20 mixtures, application of the three failure criteria led to significant differences in the fatigue life prediction; the smallest load cycles to failure (most critical) was determined based on the classic criterion. Future research should focus on establish the failure criterion to be used for pavement structural design, especially for asphalt mixtures with maximum aggregate size of 20 mm or higher.