SYMPOSIA PAPER Published: 01 January 1989

A Performance Comparison of Selected Backcalculation Computer Programs


This paper provides an overview of six different techniques which were used to estimate the “elastic modulus” of five pavement sites located in Washington State. Five of the techniques were backcalculation computer programs and the remaining one was laboratory-determined moduli (diametral and triaxial). Further, these sets of derived moduli were used to assess the needed overlay thickness (for a fixed traffic level) for each technique.

A comparison of the moduli results revealed more “agreement” than “disagreement.” Overall, the overlay thicknesses were, in general, quite similar with a few exceptions. Further, a number of factors were presented which may have contributed to some of the differences.

Author Information

Mahoney, JP
University of Washington, Seattle, WA
Coetzee, NF
Dynatest Consulting, Inc., Ojai, CA
Stubstad, RN
Dynatest Consulting, Inc., Ojai, CA
Lee, SW
University of Washington, Seattle, WA
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Developed by Committee: D04
Pages: 452–467
DOI: 10.1520/STP19823S
ISBN-EB: 978-0-8031-5087-4
ISBN-13: 978-0-8031-1260-5