Abstract

Construction Cycle 9 (CC9) was the ninth in a series of full-scale airport pavement tests performed at FAA’s National Airport Pavement Test Facility (NAPTF), the fifth involving flexible pavements. It contained four test areas: Fatigue, Geosynthetics, Cement-Treated Permeable Base (CTPB), and Overload. This report addresses the CTPB test area, which consisted of two test items with the same flexible pavement structure except for different base course materials. Test item LFS-4N had a CTPB base, while control test item LFC-4S had a conventional crushed aggregate (FAA Item P-209) base. These test items were subjected to equal simulated full-scale aircraft traffic using the NAPTF test vehicle. The goal of this test was to assess the feasibility of using a CTPB layer in a standard flexible pavement structure. Data were collected through laboratory and in situ testing, visual evaluation, and embedded pavement sensors. Embedded sensors included asphalt strain gauges, thermocouples, earth pressure cells, coil sensors, and moisture sensors. Performance was tracked by monitoring surface upheaval, rutting, and surface cracking. Key performance and sensor data were compared to an earlier test, the Construction Cycle 7 (CC7) asphalt-treated permeable base (ATPB) test item at the NAPTF. Both in-place and laboratory characterization results indicated CTPB materials had substantially higher stiffness than traditional crushed aggregate bases. Cracking and surface upheaval were lower in the CTPB test item compared to the control test item. Structural performance of CTPB under full-scale traffic may be characterized as intermediate between a standard high-quality aggregate base (P-209) and a fully bound material (P-403).