Background

The Federal Aviation Administration (FAA) built the National Airport Pavement Test Facility (NAPTF) at the William J. Hughes Technical Center, to develop reliable failure criteria for new airport pavement design procedures, through full-scale testing.  NAPTF has the capability of imparting loads representative of the new generation of heavy civil transport aircraft on typical pavement structures.  The first rigid pavements built at the NAPTF developed corner cracking during the early stages of traffic testing.  This premature failure was due to curling of the slab corners and the results were considered to be inadequate for normal life cycle determination since failures attributed to non-typical mechanisms could affect the test data obtained for development of structural failure criteria [1].  Extensive investigations were conducted prior to the construction of a second set of rigid test items to guarantee structural failure before secondary failures occurred, which included geometric design, concrete mix design, construction methods, curing, curling and warping, and trafficking of a specially constructed test strip [2, 3, 4].

The CC2 main test items were constructed in 2004 and tested during the period April – December 2004. The CC-2 test items replaced the CC-1 test items in the medium strength subgrade area of the NAPTF.

Objectives

In the new rigid construction, PCC slabs of 12 in. thickness were placed on conventional subbase, on grade and on stabilized subbase primarily to

  1. Compare life and performance for the different support conditions;
  2. Compare the pavement life and performance under 4-wheel versus 6-wheel traffic using the same dual and tandem distances in both gears;
  3. Update the failure model for rigid pavement design. 
  4. Other objectives were:
  5. Comparison of the joint efficiency data obtained from HWD tests and sensors at the joints to the 25% load transfer assumption in the design procedure;
  6. Comparison of interior and edge stresses under gear loads; and
  7. Measurement of the slabs shrinkage and curling.  
  8. Measure early-age strength gain to evaluate criteria for early opening.

References

  1. McQueen, R. D., Rapol, J., Flynn, R., “Development of Material Requirements for Portland Cement Concrete Pavements at the U.S.FAA National Airport Pavement Test Facility,” 4th International Conference on Road and Airfield Pavement Technology 2002, Kunming, China, April 23-25, 2002.
  2. Ricalde, L., McQueen, R. D., “Portland Cement Concrete Test Strip Pavement At The FAA National Airport Pavement Test Facility (NAPTF)” Proceedings of the Specialty Conference The 2003 Airfield Pavements Challenges and New Technologies, ASCE, 217-230.
  3. Guo, E., Dong, M., Daiutolo, H., Ricalde, L., “Analysis Of The Observed And Predicted Responses Of A Curled Single Slab,” Proceedings of the 2004 FAA Worldwide Airport Technology Transfer Conference & Exposition, Atlantic City, New Jersey, USA.
  4. Hayhoe, G.F., “Traffic Testing Results from the FAA’s National Airport Pavement Test Facility, ” Proceedings of the 2nd International Conference on Accelerated Pavement Testing, University of Minnesota, Minneapolis, Minnesota, 2004, USA.