Exploring indicators for fatigue cracking in hot mix asphalt pavements using simplified-viscoelastic continuum damage theory

Fatigue cracking in asphalt pavements results in decreased ride quality, decreased fuel economy, and provides an avenue for intrusion of water. Since the current asphalt mixture design relies primarily on proportioning of component materials, performance is not considered directly. An advancement in technology is to design through direct material property assessment and correlations to field performance, a performance-based mixture design. The objectives of this paper are to: (1) relate mixture stiffness, fatigue, and pavement system characteristics together for use in the performance-based mixture design; (2) identify a Simplified-Viscoelastic Continuum Damage (S-VECD) model output parameter which produces the most separation between poorly and satisfactorily performing structures when combined with dynamic modulus and phase angle information; and (3) evaluate the impact of reclaimed asphalt pavement on the performance of the indicator. A pavement response model was coupled with the S-VECD analysis to determine the fatigue life using a representative pavement structure. Results show a relationship exists between the fatigue life of the pavement system, the dynamic modulus and phase angle, as well as an energy-based index. This approach holds promise because of its reliance on material attributes that can be derived on one testing machine. The model parameters from dynamic modulus and direct tension cyclic fatigue testing can also be incorporated into performance prediction software, further enhancing the appeal of a performance specification using the approach described in this study.