Using Initiators In Portland Cement Concrete Pavements To Propagate Transverse Joint Cracking

Abstract

Past research on dowel bar placement has evaluated dowel bar misalignment relative to the saw cut at the top of the pavement. Determining misalignment measurements relative to the saw cut at the top of the pavement assumes that the crack propagates vertically downward immediately below the saw cut joint. This assumption is flawed although it is current practiced by the industry. Present detection methods cannot accurately determine the point at which the crack crosses the dowel bar. This study recognizes that there is not a technique to determine the path of the crack to measure the true misalignment but offers an alternative by dictating the crack path with cracking initiators attached to the dowel bars. Previous research has indicated that cracking initiators secured to the base of the pavement are ineffective or have little benefit due to the stress profile in the pavement slab. This study presents the results of work performed in dictating the path of a crack by attaching the crack initiator to the dowel bars. The results include utilizing different shape and size initiators. The work performed to date on crack initiation and the benefits attributed to utilization of crack initiator, including the ability to determine the true amount of misalignment are presented.