Mechanical Characterization of Tensile and Compressive Differences in Asphalt Mixtures in Multifactor Coupling

Abstract:

In response to the insufficient reliability of material mechanical parameter values in current asphalt pavement design， and based on the tensile and compressive difference characteristics of road materials， this paper conducted a study of nonlinear characteristics and quantitative relationship of tensile and compressive parameters of asphalt mixtures under the influence of multi-factor coupling. The results show that the tensile and compressive stress-strain characteristics of asphalt mixture in the elastic stage conform to the bilinear characteristics of the bi-modulus theory. The tensile and compressive mechanical parameters first increase sharply with the increase of loading speed and then tend to flatten out， and show a power function relationship. It has a negative exponential relationship with temperature， and the higher the temperature increase， the greater the decrease in mechanical parameters. The relationship between the asphalt dosage and the exponential decay model function is that the change in asphalt dosage at high temperatures （>30 ℃） has a relatively small impact on the mechanical parameters. The asphalt dosage corresponding to the maximum mechanical parameter is basically consistent with the optimal asphalt dosage obtained from the Marshall test. In terms of the degree of influence， temperature has the greatest influence on the mechanical parameters， while factors have the most significant effect on strength. The tensile strength parameter is more sensitive than the compressive strength parameter， based on which the quantitative value model of the tensile and compressive parameter of asphalt mixtures under the influence of multifactorial coupling has been established. At the specification common temperature of 15 °C （20 °C）， the ratio of compressive strength to tensile strength and the ratio of compressive modulus to tensile modulus can be 6.5 （7.5） and 1.6 （1.7）， respectively. The ratio of compressive modulus to compressive strength and the ratio of tensile modulus to tensile strength can be 400 （1 700） and 450 （2 000）， respectively.