Evaluation of fatigue behavior of aged asphalt mixtures using the simplified viscoelastic continuum damage model

Abstract

Aging of asphalt mixtures might play an important role in pavement structural behavior. That should be evaluated using mechanical models. This work aims at identifying the effects of aging on linear viscoelastic and damage behavior of asphalt mixtures, properties that influence the fatigue life of asphalt pavements. That is performed by characterizing a Hot Mix Asphalt (HMA) at four different aging states. The aged materials were obtained by heating loose asphalt mixture in oven at two different temperatures (85 and 135 °C) and aging times (2 and 45 days). Prony series were fitted to complex modulus results. For damage characterization, the Simplified Viscoelastic Continuum Damage (S-VECD) model was adopted. Damage characteristic curves and GR versus Nf failure envelopes were obtained from controlled crosshead tension-compression test results at 19 °C. It was concluded that aging produces materials that fail for less evolved damage states. However, depending on pavement conditions and layer geometry, and considering the HMA hardening, aging does not necessarily reduce the fatigue life.