多因素耦合下沥青混合料拉压差异力学特性

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

摘要:

针对现行沥青路面设计时材料力学参数取值的可靠性不足，基于道路材料的拉压差异特性，开展了多因素耦合影响下沥青混合料拉压力学参数非线性特性及量化关系研究。结果表明，沥青混合料拉压应力应变特性符合双模量理论的双线性特征；拉压力学参数随加载速度增大先急剧增加后趋于平缓，且呈幂函数关系；与温度呈负指数函数关系，且温度增幅越高力学参数减小幅度越大；与沥青用量呈指数衰减模型函数关系，高温时（>30 ℃）沥青用量的变化对力学参数影响相对较小，最大力学参数所对应的沥青用量与马歇尔试验得到的最佳沥青用量基本一致；就影响程度而言，温度对力学参数的影响最大，各因素对强度的影响最为显著，抗拉力学参数较抗压力学参数更为敏感；据此建立了多因素耦合作用下沥青混合料的拉压力学参数量化取值模型，并推荐规范常用温度15 ℃（20 ℃）下的压拉强度比及压拉模量比分别为6.5（7.5）、1.6（1.7），压缩模强比及拉伸模强比分别为400（17 00）、450（2 000）。

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.