Importance of triaxial stress state on asphalt binder tensile failure

The failure stress and strain, as well as ductility, depend greatly on the stress state to which the specimen is subjected. In previous studies of asphalt binders, the dependence of material behavior on temperature, loading rate, and aging has beenwell-examined. However, the influence of the triaxial state of stress that confines binders between mineral aggregates has not been studied extensively. In this work, a review of other materials indicates the importance of triaxiality on the failure of soft materials. Based on this review, the state of stress in asphalt materials was considered at three scales using a finite element simulation- a full depth asphalt pavement, a dense graded asphalt mixture, and a fine aggregate matrix (FAM) mix. Results indicated that the triaxiality increased as the scale became smaller. Further simulations also indicated that the poker chip test can serve as a "worst-case"scenario test where a very high triaxiality can be replicated in the lab for binder testing.