Evaluation Criteria for Aged Asphalt Concrete Surfaces; Phase II

An evaluation of aged asphalt concrete (AC) was performed during the period March–August 2007 at Polk Army Airfield (Fort Polk, LA), Redstone Army Airfield (Huntsville, AL), Simmons Army Airfield (Fort Bragg, NC), and Forney Army Airfield (Fort Leonard Wood, MO) to develop a method for predicting the performance of aged AC surfaces in situ. This research project was an extension of an investigation that was conducted in fiscal year 2006. Similar test procedures were followed for both projects. A portable seismic pavement analyzer was used on the in situ AC pavements to determine the pavement modulus. The aged AC samples obtained from the military airfields were brought to the U.S. Army Engineer Research and Development Center for laboratory testing. Dynamic shear rheometer tests were conducted on the asphalt binder samples, indirect tensile strength tests were run on core samples, and beam fatigue tests were performed on beam samples. The results from this study were used to develop adjustments to the current Department of Defense fatigue criterion to improve fatigue life predictions for aged AC surfaces. Also, the results of this investigation were used to develop fatigue criteria to be used when evaluating AC pavements in the field.