The Influence Of Different Tire Load And Temperature Field On The Mechanical Performance Of Pavement Structure

With the rapid development of transportation industry in China,a set of mature theoretical system and design method of asphalt pavement has been formed in China.However,many design parameters like tire load and equivalent pavement temperature are unified and simplified to assure the applicability.Among,a circular contact area with constant and uniform pressure is adopted to represent the tire load,ignoring the change of tire load on different road sections and the uneven distribution of tire-road contact stress.On the other hand,the pavement equivalent temperature is given according to different area,ignoring the the possible difference of temperature field between different pavement structures.From these two angles,this study aims at the influence of tire load and temperature field differences on pavement structure design with numerical simulation software.The findings are expected to provide effective theoretical guidance for the individualized design of pavement structure.A truck driving simulation software was used to establish the numerical models of secondary highway and a common two-axle truck.The change of tire load on curve,uphill slope and braking were studied.The relationship between tire load,road alignment parameters and truck dynamic factors were discussed.The results indicated that the tire load could obviously increase in special road sections.After the tire loads on different sections were obtained,a 3-D finite element pavement structure model was established to compare the pavement response and structural life prediction under uniform and non-uniform contact stress.Meanwhile,the effectiveness of Saint-Winan’s principle in pavement structure Design was discussed.It was found that the distribution of tire-pavement contact stress has great influence on the mechanical response and structural life of asphalt mixture layer,but the effects on the mechanical calculation of the bottom of inorganic binder base and the top of subgrade were negligible.Based on the measured pavement temperature field data of Zhujiang Huangpu Bridge,the heat conductivity coefficient of a kind of open-graded friction course(named as UHPP)used in the project was back-calculated by using the finite element method.Furthermore,the pavement temperature fields under UHPP and common dense graded friction course were compared.The results show that the temperature field of pavement structure can be improved by overlaying friction course with thermal resistance effect.Finally,a 3-D pavement structure ruttting calculation model was established.According to the actual road alignment,the tire load on different sections of Zhujiang Huangpu Bridge was categorized,and the temperature field under different pavement structure forms was introduced into the model.By comparison,there are significant differences in pavement rutting depth on different road sections,and the method to improve the temperature field of pavement structure can effectively reduce the rutting depth of pavement structure.