Characterization of NAPTF subgrade soils for mechanistic-based analysis and design of airport flexible pavements

Abstract

The National Airport Pavement Test Facility (NAPTF) was constructed to generate full-scale testing data to support the development of advanced airport pavement design procedures. The NAPTF material properties were characterized using test pit data obtained prior to full-scale heavy gear trafficking as well as using test data obtained from trenches opened after the completion of traffic testing. In this paper, the post-traffic subgrade characterization test results obtained from NAPTF subgrade trench sections were evaluated and compared with the pre-traffic test pit data. The combined data were used to evaluate the most commonly used correlations amongst subgrade soil properties. Subgrade moduli backcalculated from Heavy Weight Deflectometer (HWD) test data were compared with the laboratory test results and were also correlated to field California Bearing Ratio (CBR) values. Regression analyses indicated that subgrade resilient modulus is significantly related to the unconfined compressive strength. These results may be used in the mechanistic-based analysis and design of airport flexible pavements subjected to New Generation Aircraft (NGA).

Keywords:

• Resilient modulus
• NAPTF
• HWD
• CBR
• Backcalculation

Acknowledgements

This paper was prepared from a study conducted in the Center of Excellence for Airport Technology. Funding for the Center of Excellence is provided in part by the FAA under Research Grant Number 95-C-001. The Center of Excellence is maintained at the University of Illinois at Urbana-Champaign who works in partnership with Northwestern University and the FAA. Ms Patricia Watts is the FAA Program Manager for Air Transportation Centers of Excellence and Dr Satish Agarwal is the Manager of the FAA Airport Technology R&D Branch. The contents of this paper reflect the views of the authors who are responsible for the facts and accuracy of the data presented within. The contents do not necessarily reflect the official views and policies of the FAA. This paper does not constitute a standard, specification, or regulation. The authors gratefully acknowledge the help of Dr Navneet Garg, Dr David Brill, Dr Umit Seyhan, Prof. Erol Tutumluer and Dr Franco Gomez-Ramirez for their help in collecting and analyzing NAPTF materials characterization test results.

Notes

^§ [email protected]

Additional information

Notes on contributors

Marshall R. Thompson

§ § [email protected]