A Numerical-Experimental Approach to Characterize Fracture Properties of Asphalt Mixtures at Low In-Service Temperatures

摘要

Fracture damage mechanisms are some of the most significant causes of structural failure inasphalt mixtures. Yet a lot of research is still needed to properly understand the fracture processin such complex materials. This paper investigated several experimental testing protocolsavailable in the literature to characterize fracture properties of asphalt mixtures. Two bendingtests (semi-circular bending, SCB, and single-edge notched beam, SE(B)) and one tension test(disk-shaped compact tension, DC (T)) were performed in this study. An integrated approachcombining experimental tests and numerical simulations was applied to characterize fractureproperties of a fine aggregate mixture (FAM). For that, the experimental tests were simulatedusing a computational model based on the finite element method that was incorporated withmaterial viscoelasticity and cohesive zone fracture. Two cohesive zone fracture parameters, i.e.,cohesive strength and fracture energy, were determined via a calibration process until a goodmatch between experimental and numerical results was observed. To illustrate the efficiency ofthe integrated numerical-experimental approach, fracture properties were also determined by atraditional methodology that uses globally averaged material displacements far from the actualfracture process zone. The results indicated that different fracture properties at low temperaturesmay potentially be obtained from simulations of a single test, regardless of the sample geometryor loading configuration. With further testing and analysis, it is expected that the modelingapproach employed in this work can provide meaningful insights into the effects of constituentson the overall mixture’s performance, with significant savings in experimental costs and time.