Impact of Contact Stress Distribution and Pattern on Asphalt Pavement Performance using 3D-Move Analysis Software
AdvisorHajj, Elie Y.
Civil and Environmental Engineering
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This research evaluated the impact of the contact stress distribution and pattern on asphalt pavement responses and pavement performance. The impact on pavement performance was evaluated using mixtures' specific fatigue and rutting performance models. The finite-layer analytical model 3D-Move software was used to evaluate the pavement responses. Four contact stress distributions were analyzed: non-uniform, uniform circular, uniform elliptical and uniform square. A total of four pavement structures were evaluated using two different asphalt mixes and different asphalt and base layer thicknesses. Pavement responses in the various pavement structures were determined under a dual tandem axle at the braking (Longitudinal shear stress present at tire pavement contact) and non-braking (No shear stress present at tire pavement contact) conditions. The results obtained from this study showed a significant difference in pavement responses and performance for the uniform and non-uniform contact stress distributions. Overall, the uniform circular contact stress distribution, which is widely used in pavement design and analysis, overestimated the critical pavement responses such as the vertical strain in the asphalt sublayers and the tensile strain at the bottom of the asphalt layer. The non-uniform contact stress distribution resulted in lower rut depth in terms of rutting analysis and it produced lower longitudinal and transverse tensile strains at the bottom of the HMA layer when compared to the uniform circle and uniform square contact stress distribution. When compared to the other three contact stress distributions, the elliptical tire print produced lower values for the longitudinal tensile strain at the bottom of the asphalt layer for all evaluated cases, but higher transverse tensile strains at the bottom of the asphalt layer. The accuracy in estimating the new non-uniform contact stress distribution at a given load level from measured contact stress distributions using the linear interpolation/extrapolation was evaluated. The pavement responses were computed form both predicted new contact stress distribution and the measured contact stress distribution. The results obtained indicate that linear interpolation and extrapolation can be used to predict the new contact stress distribution without significant accuracy loss and this technique will yield more accurate contact stress distribution when the difference between the measured loads used to interpolate/extrapolate and the given load is small.