Discrete Element Analysis of SCB Variability—Asphalt Mixtures

Fracture of asphalt mixtures was modeled using a heterogeneous 2D-discrete element method simulating the semi-circular bending (SCB) test. The 2D internal structure was generated virtually utilizing 2D images of aggregate particles. The internal structure was produced to match specific mixes gradation, namely: superpave, porous friction course, and coarse matrix high binder mixes. The variability of SCB testing results was studied by producing 50 virtual cases for each of the mixes. In addition to randomly selecting the location of the aggregates within the internal structure, the location of air-voids was also random. The results indicated that the location of the aggregates and air-voids has a strong influence on the crack initiation, propagation and the crack path. Analysis of SCB fracture behavior for aggregates from different sources with different strength and shape properties indicated that the aggregate source plays a role in the variability, but none of the strength-shape combinations led to a significantly lower variability.