Determination of Minimum Dynamic Modulus (${\mathrm{E}}^{*}$) of High Modulus Asphalt Concrete Applied to Semirigid Base Asphalt Pavement

In order to mitigate the serious rutting disease of the semirigid base asphalt pavement (SBAP), measuring the settings of a high modulus asphalt concrete (HMAC) layer in the SBAP structure was proposed in this study. In this paper, the mechanical structure model was established according to the typical structure in the perpetual pavement (PP) design, and the mechanical response of pavement structure was analyzed, and then, the reasonable calculation points, critical failure axle load, and minimum ${\mathrm{E}}^{*}$ value of HMAC applicable to the PP structure were demonstrated. On this basis, referring to the design concept and analysis process of the PP structure, the reasonable calculation points, critical failure axle load, and minimum ${\mathrm{E}}^{*}$ value of HMAC applicable to the SBAP structure were determined, and then, the antirutting behavior of HMAC was analyzed and discussed. The results show that under the vehicle load, the SBAP structure shows different mechanical responses with the PP structure. For the PP structure, the center of wheel gap should be used as the calculation control point; differently for the SBAP structure, the center of wheel gap, the center of the load action and the edge of the load action should be respectively taken as the analysis points of antifatigue, vertical compressive stress, and shear strain. Also, the critical failure axle load of the two pavement structures was both determined as 130 kN. In order to achieve the design goal of pavement durability, the minimum ${\mathrm{E}}^{*}$ value of HMAC applicable to the PP structure should not be less than $\mathrm{14,000}\mathrm{MPa}$ (20°C, 10 Hz); while for the SBAP structure, the minimum ${\mathrm{E}}^{*}$ value of HMAC should not be less than $\mathrm{13,000}\mathrm{MPa}$ (20°C, 10 Hz). In addition, setting the high modulus layer (HMAC) in the middle and lower surface layer of SBAP structure can effectively reduce the shear deformation and the vertical deformation of the structure layer, thus improving the rutting resistance of pavement structure.