This paper describes the development of improved flexible pavement performance prediction models in which miner's linear damage hypothesis was rigorously applied in evaluating original data from the AASHO road test. Effects of seasonal variation of soil and pavement properties were considered along with the actual steering and trailing axle loads within the linear damage framework of miner's hypothesis. Separate models to predict the number of single- and tandem-axle loads sustained were developed using five mechanistic response criteria: asphalt concrete (AC) tensile strain, AC tensile stress, AC shear strain, AC shear stress, and roadbed soil vertical strain. The single- and tandem-axle models based on AC tensile strain had the highest overall precision, i.e., coefficients of determination (r-squared) of 0.83 and 0.68, respectively. The models correlate highly with road test data, but they do not compare well with other performance models or even the basic AASHO road test performance equation. The implication is that the improved models require their own set of standard 18-kip equivalency factors for use in projecting the number of load applications that would be used in designing a flexible pavement structure.
Abstract