Testing of Dowel Alignment and Development of a Dowel Bar Alignment Specification for Illinois Tollways

Dowel bar alignment is a key requirement in highway agencies’ construction specifications for jointed concrete pavement. This requirement, however, has not been rigorously enforced by most highway agencies because there has been no practical and quick means of measuring dowel alignment until recently. Since 2005, FHWA has encouraged nondestructive techniques to determine dowel alignment, principally through the use of the MIT Scan device. Separate from the measurement of dowel bar alignment is the issue of acceptable tolerances for dowel bar alignment; this involves consideration of the variability inherent in test procedures for dowel bar alignment. Many U.S. highway agencies are reevaluating decades-old tolerance limits for dowel bar alignment. This paper summarizes recent work performed for the Illinois State Toll Highway Authority to develop more rational specifications for dowel bar alignment for use on ongoing concrete pavement construction projects in the Chicago area. The specifications were devel...