Evaluation Method for Compressive Properties of Segregated Asphalt Mixtures Based on Digimat and FEM Models

Abstract

To study the mechanical properties of segregated asphalt mixtures, a novel method was developed to generate three-dimensional finite element models for segregated asphalt mixtures. The virtual uniaxial compression tests under different loading rates and test temperatures were carried out to analyze the effects of aggregate segregation on the strain distribution of asphalt mixtures. Meanwhile, the uniaxial compression tests of segregated asphalt mixtures under the same test condition were carried out in the laboratory. The results show that with the increase of aggregate segregation degree, the strain value as well as the uniformity of strain distribution for AC-13 asphalt mixture decreases, and the strain value of asphalt mortar is much larger than that of aggregate particles. The strain distribution of the asphalt mixture is related to the internal structure of the asphalt mixture, and the loading rates mainly affect the magnitude of the strain value. However, the variation of test temperature not only affects the strain distribution characteristics of the asphalt mixture but also affects the magnitude of strain value. Compared with coarse aggregate segregation of high level, the influence of loading rate and test temperature on the internal strain of nonsegregated AC-13 asphalt mixture is more significant. In terms of the laboratory result, the compressive strength of dense-graded asphalt mixture first increases and then weakens with the increase in the segregation degree of coarse aggregate, while that of open-graded asphalt mixtures enhances after the segregation of fine aggregate. Furthermore, the numerical simulation based on finite element method (FEM) effectually simulates the mechanical properties of segregated asphalt mixtures, which error is less than 6.6% when compared with the results of laboratory tests. The research results can provide some references to analyze the influence of aggregate segregation on the mechanical properties of asphalt mixture without laboratory tests.