Comparative Analysis of Using AASHTO and WESDEF Approaches in Back-calculation of Pavement Layer Moduli
Publication: Journal of Transportation Engineering
Volume 129, Issue 3
Abstract
This paper presents an evaluation of the falling weight deflectometer testing data using the AASHTO and WESDEF back-calculation procedures. General concepts of each procedure are highlighted, together with data utilized in the analysis. The back-calculated layer moduli and effective structural number of an existing flexible pavement were determined from both procedures and compared to see the difference between the procedures. The average subgrade modulus of resilience obtained from WESDEF was found to be about 0.7–0.9 of the value obtained from AASHTO with the factor (C) of 1.0. Modulus values obtained from California bearing ratio tests were in close agreement with AASHTO values only when the factor (C) was set to 0.33, the AASHTO recommended value. The analysis also suggests that a similar factor, about 0.5, for WESDEF should be used. WESDEF, without adjustment, produced higher values compared to AASHTO, with the difference being significant only at higher levels of reliability. This difference could reach 0.44 and 0.66 for reliability levels of 95 and 99%, respectively, and could result in a difference in the overlay thickness by up to 25 and 38 mm, respectively.
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References
AASHTO guide for design of pavement structures. (1993). AASHTO, Washington, D.C.
AASHTO guide for design of pavement structures, Vol. 2. (1986). AASHTO, Washington, D.C.
Ali, N. A., and Khosla, N. P. (1987). “Determination of layer moduli using a falling weight deflectometer.” Transportation Research Record 1117, Transportation Research Board, Washington, D.C., 1–10.
Elliot, R. P., and Thornton, S. I. (1988). “Resilient modulus and AASHTO pavement design.” Transportation Research Record 1196, Transportation Research Board, Washington, D.C., 116–124.
Grogan, W. P., Freeman, R. B., and Alexander, D. R.(1998). “Impact of FWD testing variability on pavement evaluations.” J. Transp. Eng., 124(5), 437–442.
Houston, S. L., and Perera, R.(1991). “Impact of natural site variability on nondestructive test deflection basins.” J. Transp. Eng., 117(5), 550–565.
PCS/Law Engineering. (1993). “SHRP’s layer moduli backcalculation procedure.” Rep. SHRP-P-655, Strategic Highway Research Program, Transportation Research Board, Washington, D.C.
Pierce, L. M., and Mahoney, J. P. (1996). “Asphalt concrete overlay design case studies.” Transportation Research Record 1543, Transportation Research Board, Washington, D.C., 3–9.
Stolle, D., and Hein, D. (1989). “Parameter estimates of pavement structure layers and uniqueness of the solution.” ASTM STP 1026, West Conshohocken, Pa.
Uzan, J., and Lytton, R. L.(1989). “Experiment design approach to nondestructive testing of pavements.” J. Transp. Eng., 115(5), 505–520.
Van Cauwelaert, F. J., Alexander, D. R., White, T. D., and Barker, W. R. (1989). “Multilayer elastic program for backcalculating layer moduli in pavement evaluation.” ASTM STP 1026, West Conshohocken, Pa.
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Copyright © 2003 American Society of Civil Engineers.
History
Received: Nov 8, 2001
Accepted: Apr 9, 2002
Published online: Apr 15, 2003
Published in print: May 2003
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