Use of Slab Curvature and ProVAL to Identify the Cause of Premature Distresses

It has been argued that dynamic traffic loading due to the presence of a nonflat pavement shape may result in accelerated deterioration of the pavement because of higher stresses in the slab from restrained curling–warping movement. Slab curvature, though imperceptible to the naked eye, usually develops on the riding surfaces of the individual slab segments after construction. Select case studies on high- and low-altitude Bolivian concrete highways illustrate the magnitude of curvatures that are generated. The Butterworth high-pass and spectral density analysis tools in the ProVAL software are used to identify the pavement slab curvature in these projects. A mechanistic analysis is used to ascertain the causes of the observed longitudinal cracking. By resorting to a newly developed curvature index, the second-generation curvature index, the equivalent temperature gradient that corresponds to the fitted curvature was included in a finite element method analysis to determine stresses in the slabs. It is concluded that the curved shape of the slabs resulting from permanent curling–warping coupled with traffic loading is inducing excessive stresses and causing the observed cracking distress in one of the evaluated highways.