Experimental Investigation of Effects of Dowel Misalignment on Joint Opening Behavior in Rigid Pavements

Experimental investigations were conducted to determine the fundamental joint opening behavior of concrete pavements and to evaluate the effects of dowel misalignment on this behavior. The parameters included in the experimental investigations were the number of dowel bars (one, two, three, or five) at the joint, the dowel misalignment type (horizontal, vertical, or combined), misalignment magnitude (0, 1/36, 1/18, 1/12, 1/9 rad), and uniformity across the joint. The effects of these parameters were evaluated for the joint opening behavior and structural distresses observed in the specimens. Forty-seven instrumented laboratory-scale specimens of pavement slabs with doweled joints were tested. The experimental results include the load per dowel–joint opening behavior and observations of structural distress. These results indicate that (a) all pavement joints are initially locked, and opening displacements occur after the load per dowel exceeds 5 to 7 kN or the average bond shear stress exceeds 0.22 to 0.30 MPa; (b) for all misalignment types, the load per dowel increases with larger misalignment magnitudes and nonuniformity; (c) structural distress in the form of concrete spalling and transverse cracking was observed for specimens with larger dowel misalignments and nonuniformity; and (d) severity of structural distress increased with the number of misaligned dowels at the joint. These experimental results do not provide comprehensive knowledge regarding the mechanics of dowel–concrete interaction, and analytical investigations are needed to address this limitation.