Evaluation of Moisture Sensitivity of Hot Mix Asphalt by Flexural Beam Fatigue Test

The research presented in this paper developed a test protocol for using the flexural beam fatigue test to evaluate the moisture sensitivity of hot mix asphalt (HMA). The following test parameters were determined: vacuum intensity and duration for pre-saturating specimens, preconditioning temperature and duration before the fatigue test, and temperature and strain level during the fatigue test. An experiment was designed to include two aggregates, two binders, and one antistripping additive for testing by this procedure. The indirect tensile strength ratio (TSR) test and the Hamburg Wheel Tracking Device (HWTD) test were also performed on the same mixes. Generally, the three test methods did not give consistent results in terms of relative ranking of performance. The flexural beam fatigue test showed potential capability to evaluate moisture sensitivity of HMA, but further refinement is needed.