ABSTRACT
ABSTRACT: Full-scale testing of three new rigid pavement test items took place at the Federal Aviation Administration (FAA) National Airport Pavement Test Facility (NAPTF). Pavements were trafficked to complete failure with 4-and 6-wheel gear loads. The performance of slabs under traffic was monitored using visual surveys, crack mapping, destructive and nondestructive testing. Cores recovered from cracked areas of the slabs revealed that some cracks initiated from the surface (“top-down”), while others initiated from the bottom surface (“bottom-up”) or were inconclusive. By analyzing data from the in-pavement sensors, it was possible to supplement the information from the visual surveys and destructive tests. The gage data supplied new information about the relative prevalence of top-down versus bottom-up crack initiation, as well as the timing of crack formation. This is a key consideration for future development of the FAA’s rigid design procedures, which currently consider a single failure mode based on bottom-up cracking.
