Design, Construction, and Performance Monitoring of Ultra-Thin Whitetopping at a General Aviation Airport: Fid-Bau Portal

Design, Construction, and Performance Monitoring of Ultra-Thin Whitetopping at a General Aviation Airport

Saeed, Athar / Hammons, Michael I. / Hall, Jr., Jim W.

The first ultra-thin whitetopping (UTW) project on a general aviation (GA) airport in the U.S. was constructed in April 2000 at the Savannah-Hardin County Airport (SNH), Tennessee. This paper provides field evaluation details and summarizes the procedure used for determining the UTW thickness. The existing asphalt concrete (AC) surface was aged and had experienced significant fatigue and thermal cracking. Existing surface conditions were assessed using the concepts of pavement condition index (PCI), and the structural capacity was estimated using the falling weight deflectometer (FWD) and the dynamic cone penetrometer (DCP). Current pavement conditions, structural capacity, and subsurface soil conditions were evaluated to determine pavement design parameters and to make design recommendations. A 2-D finite element code (ILLI-SLAB) was used to calculate deflections and stresses in the UTW. The maximum bending stresses were subsequently used in the Portland Cement Association (PCA) fatigue law to determine the allowable number of load repetitions. A 100-mm thick UTW on top of the existing AC surface with a joint spacing of 1020 mm was recommended based on design calculations. Adequate bond between UTW and the existing AC pavement is essential for satisfactory UTW performance. Strain gages were installed near the surface and bottom of the PCC, and on the top of the milled AC surface to determine if the UTW is completely bonded, completely unbonded or partially bonded to the milled AC surface. The summer season data collected in June 2000 indicated a good bond between UTW and milled AC surface. The next round of data collection (winter season) and analysis is planned for February 2001.