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Proceedings Paper

Back-calculation of temperature parameters for determination of asphalt layer modulus
Author(s): Qinxi Dong; Kunihito Matsui; Kazuya Yamamoto; Shigeo Higashi
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Paper Abstract

The pavement elastic modulus of each layer was usually assumed not to be dependent on the environmental factors when the backcalculation of asphalt pavement was conducted from the measured surface deflections of FWD. However, it is well known that the elastic modulus of asphalt layer changes with the variation of temperature. Considering the influence of atmospheric temperature and radiant heat, the temperature distribution is nonlinear along the asphalt layer thickness, and has always been changed. Therefore, the distribution of elastic modulus in the asphalt layer has been considered to change as well. In this paper, we assume the elastic modulus distribution of the asphalt layer to vary with its temperature in terms of the exponential form. Based on the finite element method forward analysis, we propose a method to estimate a standard elastic modulus and temperature coefficient at 20 degrees Celsius for the asphalt layer from the backcalculation analysis. The corresponding FEM backcalculation program using Gauss-Newton method was developed to determine the pavement layer moduli and temperature dependent coefficient, in which the singular value decomposition (SVD) was used for the inverse analysis with scaling of unknown parameters. This method results in a smaller condition number that contributes to improvement of numerical stability. Both numerical simulation and measured data from FWD testing are used to demonstrate the potential applications of this method. As a result, the backcalculation procedure is less dependent on the user's initial values, fast in convergence rate and effective in the pavement engineering.

Paper Details

Date Published: 13 May 2000
PDF: 12 pages
Proc. SPIE 3993, Nondestructive Evaluation of Aging Materials and Composites IV, (13 May 2000); doi: 10.1117/12.385483
Show Author Affiliations
Qinxi Dong, Tokyo Denki Univ. (Japan)
Kunihito Matsui, Tokyo Denki Univ. (Japan)
Kazuya Yamamoto, Tokyo Denki Univ. (Japan)
Shigeo Higashi, Technical Institute of Kajima Road Construction Corp. (Japan)


Published in SPIE Proceedings Vol. 3993:
Nondestructive Evaluation of Aging Materials and Composites IV
George Y. Baaklini; Carol A. Nove; Eric S. Boltz, Editor(s)

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