Program BIMODPAV for analysis of flexible pavements

A new axisymmetric finite-element pavement-analysis program BIMODPAV capable of accounting for the bimodular nature of the asphalt concrete is developed. The program also considers the nonlinear behavior of the base, sub-base, and subgrade layers. The new program was verified with the existing programs within their capabilities. The effect of considering the bimodularity of asphalt concrete in the analysis is apparent at high temperatures and when it is used for thick pavements. Strains and displacements calculated using the bimodular analysis are almost always higher than the strains and displacements calculated using the single-modulus approach. When asphalt concrete is characterized as a bimodular material and its underlying layers as nonlinear materials, the displacements and strains are as much as twice the corresponding single-modular solution. Bimodular analysis of asphalt concrete causes higher tensile strains at the bottom of the asphalt layer and higher vertical strains on top of the subgrade resulting in reduced fatigue and rutting performance predictions.