This paper describes a mechanistic-empirical design procedure developed to assist pavement engineers in determining when flexible overlays of flexible pavements will develop reflection cracking. A mechanistic equation based on fracture mechanics was developed to predict when reflection cracking was expected to occur. Data on in-service pavements were collected for six environmental regions. The equations were used to predict the occurrence of reflection cracking. The performance data were then used to calibrate the mechanistic equations to three different damage levels. The final design equations wereplaced in a user-friendly microcomputer design program. This paper tries to demonstrate the data collection requirements and problems associated with developing mechanistic-empirical design equations. This approach to developing design equations has great promise; however, the data must be complete and accurate for the approach to be used fully. Some of the problems encountered are described, along with the approaches used to solve these problems. This paper appears in transportation research record no. 1196, Pavement evaluation and rehabilitation.
Abstract