Exploring Mechanism of H ealing in Asphalt Mixtures and Quantifying its Impact

Any treatise on healing in asphalt pavements must begin with an answer to the question: “How important is healing in asphalt pavements?” Experience clearly tells us that it is substantially important. Shift factors from laboratory-predicted to fieldobserved fatigue cracking demonstrate that laboratory data underpredict field observations. A variety of reasons are responsible for the use of shift factors including traffic wander, time of crack propagation, difference in stress states between the laboratory and the field, and crack healing. The shift factor developed by the Asphalt Institute from AASHTO Road Test (laboratory-to-field) data is 18.3.