Reflective cracking included into routine design of new asphaltic pavements

Abstract

During the past decades, it has been experienced that reflective cracking is a very complex phenomenon. Not only which one of the possible mechanisms behind the reappearance of cracks in new pavement surfaces (traffic, temperature variations in time or uneven settlements) is dominant, depends on the typical circumstances of a specific project, but also a variety of maintenance solutions often seems to be applicable. Examples are: (combinations of) thick overlays, use of modified asphaltic mixtures, application of stress-relieving systems or the incorporation of reinforcement. At motorway and airfield (maintenance and rehabilitation) projects there usually is time, budget and information. At those large projects it pays tribute to include reflective cracking into the routine design, because a cement treated base or concrete slabs are quite often present. From these specific pavement layers, cracks or joints propagating into and through the asphaltic overlay is the dominant mechanism. Ooms Civiel has developed an analysis method to include the crack driving mechanisms temperature variation and traffic into the routine design of new asphaltic pavements. The temperature influence is analysed by means of ARCDESO®; the traffic loading requires finite elements simulations. This paper explains the design method, which meets the challenge mentioned above. The method has been calibrated with long term field experience (crack mapping data) and is being validated continually.