Fracture modeling of rubber-modified binder based on Discrete Element Method

This study investigates the effects of rubber on anti-crack resistance for binders at the low temperature based on Discrete Element Method (DEM). Based on the commercial software Particle Flow Code (PFC), cohesive zone modeling (CZM) and viscoelastic modeling were combined for predicting the behavior of unmodified and Ground Tire Rubber (GTR) modified binders. A new binder fracture test was designed and further simulated in PFC to reveal the interactions between the rubber and binder particles. Then, fracture analysis was conducted in different aspects, including fracture energy, Load-CMOD curves which are mechanics indices, evolutions of crack length, crack number and fracture process zone (FPZ) etc., which are morphological indices. Results from simulations show that the rubber particles play an important role in improving the anti-crack performance of binders at the low temperature. The rubber modified binder will have a ductile failure mode rather than brittle one of unmodified binder, resulting in higher fracture energy. The evolutions of micro-cracks, FPZ and dissipated energy are significantly influenced by rubber particles, which explain the reason for better post-peak behavior, larger peak load of GTR modified binder in macro fracture tests.