Effect Of Built-In Curling On Concrete Pavement Performance And Design In Chile

Built-in curling (BIC) is a permanent upward curvature of the concrete slab produced by irreversible moisture and temperature differences between the top and the bottom of the slab. This residual curvature has been shown to change the performance of concrete pavements. With mechanical loading, built-in curling typically changes the location and magnitude of the maximum tensile stress in the slab as larger regions of the slab are without contact with the support layer. Two existing concrete pavement projects in Chile were selected to characterize their in-situ BIC, document their performance, and determine if existing design procedures can adequately predict and account for their performance differences. In both case studies, BIC had a large effect on pavement performance and the magnitude of the effective built-in temperature difference, which is an important design input to predict the performance life. For one of these projects, premature slab failures resulted due to the initial BIC. The concrete thickness would needed to be increased by 59% or the slab size reduced to 2.00 m x 1.75 m to avoid premature failure of the section due to the high level of BIC. In the second project, the section of the concrete pavement that performed best was constructed at night and had a lower BIC relative to the sections constructed during the daytime in the summer.