Integrated Experimental and Numerical Study on Permanent Deformation of Asphalt Pavement at Intersections

Abstract

It has been observed that permanent deformation (or rut) in the asphalt pavement at an intersection is much more severe than a deformation away from the intersection due to breaking horizontal forces and longer loading time. This paper presents both experimental and numerical investigations of this phenomenon, and the numerical investigations are validated by three-dimensional fiber-reinforced polymer-optical fiber Bragg grating sensors. First, a field investigation of the rutting at four signalized intersections in Nanjing (Jiangsu, China) leads to the conclusion that under braking traffic and static loads, the values of voids in the mineral aggregate (VMA) and air-void content could be less than the minimum desirable values. Second, the permanent deformations associated with tangential and vertical forces and their loading time assessed with the finite-element method are compared with those measured from instrumentations. This analysis demonstrates that hot-mix asphalt pavement at the intersections should maintain adequate VMA to ensure durability, and a minimum desirable percentage of air voids under slow and standing traffic loads during hot summer days. The permanent deformations at the intersections caused by tangential and vertical forces are both serious and need to be restricted. It is also shown that the permanent deformation is sensitive to both the traffic load and its loading time, but the sensitivity of the load is more pronounced.