Abstract
Accurate structural evaluation of flexible pavements is important for cost-efficient maintenance and rehabilitation (M&R) strategies. Traditional back-calculation methods based on Falling Weight Deflectometer (FWD) data assume elastic behavior, overlooking the viscoelastic nature of asphalt materials and subsequently leading to inaccuracies. This study introduces a mechanistic-based back-calculation technique to estimate the dynamic modulus (E*) master curve directly from FWD time-history data. By integrating layered elastic theory with viscoelastic principles, the proposed method first determines the relaxation modulus, E(t), using Differential-Time Fourier Transform (DTFT) analysis. This time-domain response is then converted into the frequency domain to construct the E* master curve. Validation against laboratory-measured dynamic modulus values from field-cored specimens demonstrates that the proposed technique generates highly accurate E* master curves for all asphalt layers. Moreover, the findings highlighted the importance of accurate pavement structural information, such as layer thickness and Poisson’s ratio, for achieving reliable E* master curve.
Keywords
mechanistic technique, backcalculation, FWD, dynamic modulus, master curve, nondestructive testing, asphalt pavement
Report Number
FHWA/IN/JTRP-2025/18
SPR Number
4619
Sponsoring Organization
Indiana Department of Transportation
Performing Organization
Joint Transportation Research Program
Publisher Place
West Lafayette, Indiana
Date of Version
2025
DOI
10.5703/1288284317898
Recommended Citation
Notani, M. A., Cho, S., & Haddock, J. E. (2025). Backcalculated dynamic modulus master curve from the time histories of falling weight deflectometer surface deflections (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2025/18). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284317898
SPR-4619 Technical Summary