Validation of a simplified method in viscoelastic continuum damage (VECD) model developed for flexural mode of loading

• Simplified VECD model using peak-to-peak values of stress and strain is applicable in flexural mode of loading.
• Material constant (α) has inverse relationship with slope of the central portion of the relaxation modulus curve obtained from the flexural dynamic test.
• There is only limited range of initial pseudostiffness (I) for which the errors in calculation of damage parameters could be neglected.

Viscoelastic continuum damage (VECD) is a powerful method to describe fatigue behavior of asphalt concrete mixtures by implementing the fundamental mechanistic principles. In this study, peak-to-peak values of stress and strain are used to simplify the calculation of damage parameters in VECD model using cyclic flexural fatigue test. Fatigue tests have been conducted over a range of strain and frequency levels. It was observed that excluding the samples with initial pseudostiffness (I) less than 0.74, other specimens’ characteristic curve overlaps on a unique curve for any set of loading. Also, the results showed that there is an inverse relationship between the material constant (α) and the slope of the central portion of the relaxation modulus curve obtained from a flexural dynamic test using 4-point bending beam apparatus.