Effects of Temperature and Moisture Gradients on Slab Deformation for Jointed Plain Concrete Pavements

Abstract

Slab curvature, which represents the response of concrete pavement slabs to environmental loads, influences the location and magnitude of critical slab stresses and affects long-term pavement performance. The purpose of this study was to measure the changes in temperature and moisture profiles in a newly constructed concrete pavement and to determine both the overall deformed shapes of the slabs as well as the relative contributions of built-in and transient environmental effects over time. Data were collected from an instrumented jointed plain concrete pavement (JPCP) over a 2-year period. Slab curvatures were computed or predicted using measurements of temperature and moisture conditions in the slab, static strain measurements, and pavement surface profile measurements. It was found that the additional restraint provided by the dowel and tie bars does not appear to significantly reduce slab curvature resulting from daily temperature fluctuations or from reversible drying shrinkage. It does have a substantial effect on reducing slab curvature attributable to long-term drying shrinkage. It was also found that the Mechanistic-Empirical Pavement Design Guide default value is close to that measured in this study for the restrained slab but does not appear to be appropriate for unrestrained (i.e., undoweled) slabs.