Structural and functional deterioration of porous asphalt pavement under moving wheel load in laboratory

In Japan, the structural design method of porous asphalt pavement is presently empirical, and in order to apply porous asphalt pavement to heavy traffic roads in urban areas, the progress of both structural and functional damage to porous asphalt pavement due to traffic loads needs to be grasped. This paper describes an attempt that was made to understand the damage progress of porous asphalt pavement by carrying out a moving wheel load test on an instrumented small-scale porous asphalt pavement. The pavement consisted of a porous asphalt surface/binder layer, an asphalt-treated porous base-course, a crusher-run subbase-course and a sandy subgrade. The test was conducted in series with four conditions of (a) room temperature, (b) pavement surface temperature of 60 degrees C, (c) room temperature after watering and (d) pavement surface temperature of 60 degrees C after watering. It is shown that the load transmission function deteriorates with the number of wheel passing, especially under the higher temperature, that permeability in the rutted track is smaller than that in the other locations, and so on. This permeability deterioration is attributed to accumulated plastic deformation in the pavement but it is not easy to identify which layer controls this.