A Simplified Overlay Design Model against Reflective Cracking Utilizing Service Life Prediction

ABSTRACT Although it is the major mode of failure in rehabilitated pavement structures, reflection of cracking seldom has been considered in the overlay design process mainly due to its complexity. This paper presents the development of an overlay design procedure to predict the service life of rehabilitated flexible pavement structures against reflective cracking. A simple equation was derived based on three-dimensional (3D) finite element (FE) models and by utilizing linear elastic fracture mechanics (LEFM) principles. The FE models simulate a variety of rehabilitated cracked pavement structures. A detailed sensitivity analysis was performed to establish the accuracy of the FE models. Then, accurate simulation of the crack singularity was achieved by modeling several contour integral evaluations along the crack front. Both crack initiation and propagation phases were considered in the formulation. The crack initiation phase is described using a traditional fatigue law developed by the Belgium Road Research Center, and the crack propagation phase is described using Paris-Erdogan phenomenological law. Three contour lines were used around the crack front to calculate the path-independent J-integral. Calculations of the stress intensity factors based on the J-integral are presented. An example is presented to demonstrate the use of the developed design equation in a routine overlay design.