Field Investigation of Dowel Misalignment and Potential for Joint Lock-Up

A field investigation was performed to determine the impact of dowel misalignment on joint movements and potential for joint lockup on a section of a newly constructed concrete pavement in Florida. This section of the pavement exhibited various types and degrees of dowel misalignment. Lacking a widely accepted rejection criteria, the joint score methodology published by the Federal Highway Administration (FHWA) was used to identify joints that were considered problematic. Joint scores were computed for each of the joints as indicated in the procedure. The scores generally ranged from 1 to 40 with a joint score of 1 indicating perfectly aligned dowel bars at a joint and 40 indicating a joint with a high degree of misalignment in multiple bars. The rejection criteria were initially planned to be based on the Joint Scores, however, based on a meeting between the owner, the designer, and the builder, a novel approach to arriving at the criteria based on direct measurements of the joint movements in the field was followed. This approach included measuring movements of joints with severely misaligned dowels and well-aligned dowels over a 48-hour period. The resulting data showed unexpected but conclusive evidence that suggested that more work needs to be done in establishing rejection criteria and corrective actions when dowel misalignment is detected in the field.