Effects of moisture damage and anti-stripping agents on hot mix asphalt dynamic modulus

This paper presents findings from a comprehensive model of dynamic modulus (|E*|) of mix asphalt estimated with the statistical approaches of joint estimation and mixed-effects. The model consists of a typical sigmoidal master curve using a different parametrization of sigmoidal function, including the effects of binder, voids, gradation, fibres, confinement level, freeze–thaw cycles, and antistripping agents. This paper concentrates on the engineering implications related to the effects of freeze–thaw cycles and antistripping agents. The estimation results indicate that the number of cycles affects three terms of the sigmoid. The contribution of each term changes with reduced frequency but the net effect is always a reduction of log (|E*|) with a given number of cycles for any reduced frequency, with proportionally larger effects at lower reduced frequencies. The effects of freeze–thaw cycles can be completely counteracted by an antistripping agent but it depends on the number of cycles and the frequency.