Six flexible pavement test sections were constructed on the North side for Construction Cycle 7 (CC7) at the Federal Aviation Administration’s (FAA) National Airport Pavement Test Facility (NAPTF). The research objectives for CC7 are: to develop flexible perpetual pavement design criterion, and to validate/refine/modify the fatigue model for hot mix asphalt (HMA). Full-scale tests are in progress on these pavement test sections under heavy aircraft gear loads using the National Airport Pavement Test Vehicle (NAPTV). The uniformity of the pavement structure within each testing section was characterized from heavy weight deflectometer (HWD) test results. A series of HWD tests were regularly conducted to monitor the performance of the pavement structure during accelerated pavement testing. Deflection basin shape factors (ISM, AREA, AUPP and ABSP) were calculated from measured deflection basins. The mechanical behavior of asphalt concrete is sensitive to the temperature. Two parameters were utilized to compare the results from tests conducted at different temperatures. The first parameter is the ratio of the deflection basin shape factor between traffic and non-traffic area. Additionally, a temperature shift factor was used to calculate the equivalent deflection basin shape factor at a reference temperature for HWD results obtained at different temperatures. Thermocouples were installed in the asphalt concrete layer. The average pavement temperature during tests was 43.5 ºF and was selected as the reference temperature. The deterioration of flexible pavement structures due to traffic is evaluated using both parameters. The results indicate that there is a strong correlation between asphalt concrete layer deterioration and increase of AUPP and ABSP value. The reduction of ISM and AREA values reflect the deterioration of the whole pavement structure.

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