Effects of heavy truck braking on inverted asphalt pavement considering vehicle dynamics

Abstract

Inverted asphalt pavement is an innovative pavement structure where the unbound aggregate base (UAB) is sandwiched between the asphalt concrete (AC) layer and cement-treated base (CTB). This structure has the potential to improve rutting resistance of pavement and prevent propagation of reflective cracks. However, its implementation has been limited due to the lack of experience. In addition, the braking condition of the vehicle applied on the pavement surface plays a significant role on the pavement responses, thereby affecting its service life. This study conducted a simulation using finite layer method to investigate the effects of heavy truck braking on inverted asphalt pavement considering vehicle dynamics. The results indicated that truck braking would generate a significant horizontal load and change the magnitude of the vertical load at each axle. Furthermore, the impact of vertical load on mechanical responses would gradually enhance and eventually dominate with increasing pavement depth. It was also observed that when the truck was treated as a whole, vehicle braking would result in a 3.2% to 10.2% increase in critical responses, but cause a 0.023% and 31.7% decrease in predicted rutting and life respectively. Among three truck axles, the effect of driving axle was close to that of the entire truck, but the effect of other axles was greater or lower than that of the entire truck. A comparison of three inverted pavements found that a thick AC layer could effectively reduce the critical responses and extend the pavement life. Furthermore, a thick CTB layer could also achieve most of the above purposes due to higher integral stiffness of pavement.