Cracking and spalling of concrete pavements reduce the service life of the roadway and result in added costs to an agency and disruptions to the traveling public when the damage is repaired.
Cracks and spalls in concrete occur due to a wide range of reasons, but a recently completed study funded by the National Road Research Alliance focused on the effect of dowels and tie-bars in pavement.
Dowel bars and tie bars are typically made of steel, which is stiffer than hardened concrete by about a factor of five to ten. A literature review and field studies suggest that under some conditions, restraint caused by dowel bars and tie bars in the concrete result in high early age stresses that contribute to cracking. The field evaluation showed that the cracks within the concrete typically start around the depth of the dowel bar near the joint as delamination cracks and then migrate upward toward the surface, eventually breaking up and spalling the concrete.
To gain a more detailed understanding of this process, the authors propose a second phase analysis including an evaluation of key parameters and their influence on dowel bar cracking followed by validation through laboratory experimentation and model refinement.
More information:
Crossroads 