Numerical implementation of a strain energy-based fracture model for HMA materials

• This work combines a new strain energy-based fracture criterion with a viscoelastic displacement discontinuity boundary element method to investigate crack growth in hot mix asphalt (HMA) materials. The study employs a fundamental crack growth threshold and simulates crack growth by accumulation of the dissipated creep strain energy (DCSE) below this threshold, only healable micro-damage develops, and non-healable crack initiation or growth occurs, otherwise. A critical zone is introduced ahead of the crack tip to represent the portion of the material being damaged. Once the cumulative micro-damage inside the critical zone reaches the cracking threshold, the crack extends by the length of the critical zone. An HMA fracture simulator is developed by incorporating the DCSE threshold concept into a numerical framework based on a viscoelastic displacement discontinuity method, which has proven its convenience and efficiency in crack modeling. Numerical analyses are performed to predict piecewise crack propagation in asphalt mixtures using the HMA fracture simulator, and laboratory experiments are also conducted to verify and validate the numerical model.

Nyckelord

crack growth

HMA materials

viscoelastic DDM

dissipated creep strain energy

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