Evaluation and modelling of low-temperature fracture properties of asphalt binders in thin film by means of the local fracture test

The experimental investigation focuses on evaluating fracture properties of asphalt binders at low temperatures through the Local Fracture Test. The test consists in subjecting a thin film of binder to controlled tensile loads, simulating the response of the material inside the pavement. The methodology adopted combines laboratory measurements and FEM simulation. The model describes the theoretical response of the sample when a crack of variable size appears, integrating linear viscoelasticity and sample geometry. Different materials are compared, based on their fracture energy determined from the force–displacement curves. A specific criterion is proposed to determine the critical fracture temperature for each binder. Outcomes showed the effectiveness of the adopted methodology in evaluating the fracture properties of investigated materials. Moreover, a high correlation between the critical temperatures derived from the Local Fracture Test and the glass transition temperatures coming from Dynamic Mechanical Analysis was found for the unmodified binders.