沥青路面结构设计指标优化及合理厚度探究

With the rapid development of transport field in China, a variety of asphalt pavement structure forms have been proposed and applied. The existing pavement structure design indicators are proposed for typical pavement structures, their applicability to atypical pavement structures needs to be verified. In order to verify the applicability of structural design indicators of atypical asphalt pavement structures, to determine the reasonable thickness range of typical pavement structures, and to improve the structural design method of asphalt pavement, first, the typical and atypical asphalt pavement structural models under moving non-uniformly distributed load are established, and the design indicators of the pavement structures are analyzed according to the mechanical response rule. Then, the pavement service lives under moving non-uniformly distributed load and static double-circular uniformly distributed load are compared, and the design indicators of each pavement structure are given. Finally, change the thickness of each pavement structural layer, the reasonable thickness range of the semi-rigid base pavement is determined according to the calculated pavement service lives. The result shows that (1) the calculation value of pavement service life under static double-circular uniformly distributed load is 0.7-0.9 times of that under moving non-uniformly distributed load, thus the non-uniformly distributed load movement should be considered in pavement mechanics analysis; (2) for semi-rigid base pavement, flexible base pavement, long-life pavement, inverted structure pavement and anti-rutting pavement, the vertical compressive strain on the top of subgrade could not be taken as the design indicator; (3) the type of pavement has great influence on the applicability of the design indicators, so the design indicators should be determined according to the type of pavement; (4) for semi-rigid base pavement with base course thickness less than 250 mm, the service life of pavement increases first and then decreases with the increase of asphalt surface thickness, and the control indicator changes from tensile stress at the bottom of the inorganic binder course to permanent deformation of the asphalt binder course. However, for semi-rigid base pavement with surface thickness more than 200 mm, the control indicator of pavement service life is the permanent deformation of asphalt mixture layer, increasing the thickness of surface course will reduce the service life of pavement.