RELATIVE PERFORMANCE OF CC6 CONCRETE PAVEMENT TEST ITEMS AT THE FAA NATIONAL AIRPORT PAVEMENT TEST FACILITY

Between August 2011 and April 2012, six rigid pavement test items, designated CC6, were trafficked to full structural failure at the Federal Aviation Administration (FAA) National Airport Pavement Test Facility (NAPTF). The primary objective of these full-scale tests was to investigate the effect on pavement life of concrete flexural strengths higher than recommended by current FAA standards in Advisory Circular (AC) 150/5320-6E. The six test items were constructed using three different concrete mixes with different flexural strengths. All test items were subjected to traffic from 4-wheel landing gears in a 2D configuration. Pavement condition was continuously monitored, and traffic was continued until the structural condition index (SCI) of all test items was under 30, which is well below the design failure condition of SCI 80. Due to the significantly different flexural strengths, it was necessary to vary the gear loads to achieve failure of all test items in a reasonable number of traffic passes. Moreover, all test items (except one) received traffic at a mixture of different load levels. Therefore, in order to compare test item performance, it was necessary to introduce mixed aircraft traffic concepts to the analysis. A rational method of compensating for various load levels, making use of the cumulative damage factor (CDF), results in equivalent traffic passes to failure at a reference wheel load, so that the effect of concrete strength can be clearly observed. Using this method, it was demonstrated that CC6 pavement life was strongly correlated to 28-day flexural strength, and was not strongly affected by the base type.