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 in asphalt mixtures. Yet a lot of research is still needed to properly understand the fracture process in such complex materials. This paper investigated several experimental testing protocols available in the literature to characterize fracture properties of asphalt mixtures. Two bending tests (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 approach combining experimental tests and numerical simulations was applied to characterize fracture properties of a fine aggregate mixture (FAM). For that, the experimental tests were simulated using a computational model based on the finite element method that was incorporated with material 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 good match between experimental and numerical results was observed. To illustrate the efficiency of the integrated numerical-experimental approach, fracture properties were also determined by a traditional methodology that uses globally averaged material displacements far from the actual fracture process zone. The results indicated that different fracture properties at low temperatures may potentially be obtained from simulations of a single test, regardless of the sample geometry or loading configuration. With further testing and analysis, it is expected that the modeling approach employed in this work can provide meaningful insights into the effects of constituents on the overall mixture’s performance, with significant savings in experimental costs and time.