Early-Age Curling and Warping Behavior: Insights from a Fully Instrumented Test-Slab System

Abstract

A concrete slab was constructed at Texas A&M University to study temperature, moisture, and creep effects on the curling and warping behavior of jointed concrete pavements under different curing conditions. A saw-cut joint was placed at the mid-slab location, where one half of the slab was cured with a standard curing compound and the other half was mat-cured. The half of the slab under membrane curing was subjected to a larger built-in curling and shrinkage than the half that was matcured. Because of differences in the amount of shrinkage and creep between the two curing methods during the hardening process, the two halves of the slab showed different early-age behaviors with respect to strain and vertical displacement. The dowels also affected the early-age behavior of the slab at the saw-cut joint. A linear relationship was found among measured vertical corner displacements, concrete strain, and calculated dowel bending moments. The equivalent temperature differences calculated by ISLAB 2000 present the effects of shrinkage and creep on the curling and warping behavior of the slab.

Environmental Effects on Deformation and Smoothness Behavior of Early-Age Jointed Plain Concrete Pavements

“…Because both of these programs can simulate slab deformation that results from environmental loading in relation to temperature changes, it is necessary to establish the relation between actual measured temperature difference and equivalent temperature difference associated with the actual pavement behavior. With a methodology similar to that adopted by previous researchers (5,41,42), equivalent temperature differences for both FE programs were backcalculated to generate the relative corner deflection-to-center profile measurements. Figure 7 shows that there is a linear relation between the equivalent temperature difference and the measured temperature difference.…”

Finite element modeling of environmental effects on rigid pavement deformation

“…Therefore the concept of combining all of the active effects into an 'equivalent temperature difference' has been used by previous researchers (Rao et al, 2001;Yu and Khazanovich, 2001;Jeong and Zollinger, 2004;Rao and Roesler, 2005). Using this concept, the relation between actual measured temperature difference and equivalent temperature difference associated with actual pavement behavior could be established.…”

A Simplified Approach for Predicting Early-Age Concrete Pavement Deformation / Supaprastintas Metodas, Prognozuojantis Ankstyvojo Betono Dangos Deformacijas

“…The total environmental effect resulting in PCC slab deformation is represented as a temperature difference between top and bottom of slab -the total equivalent linear temperature difference (TELTD), Yu et al 2004;Rao and Roesler 2005): ). Although the total environmental effect resulting in slab displacements could be theoretically decomposed, the concept of an equivalent temperature difference to combine all the active effects has more often been used by researchers (Rao et al 2001;Jeong and Zollinger 2004;Rao and Roesler 2005;) since the environmental effects are highly correlated with each other and some effects such as non-uniform moisture distribution are difficult to quantify in terms of temperature difference. Hiller and Roesler (2005) …”

“…Using the concept of equivalent temperature difference, the relation between actual measured temperature difference and equivalent temperature difference ( teltd T ∆ ) associated with actual pavement behavior could be established. Similar to the approach used by previous researchers (Rao et al 2001;Yu and Khazanovich 2001;Jeong and Zollinger 2004), equivalent temperature differences of FE program were back-estimated to generate the relative corner deflection to center of the measured slab curvature profiles from diagonal direction. Once the teltd T ∆ on given measured temperature difference was estimated, the teltd T ∆ values were plotted with measured temperature differences as shown in Fig.…”

“…However, the actual temperature distributions should be adjusted in these programs to provide prediction of deformation due to moisture variations and permanent deformation which can be obvious during early age of the PCC (Rao et al 2001). For this purpose, researchers have recently attempted to convert the all of environmental effects into an "equivalent temperature difference" (Rao et al 2001;Yu and Khazanovich 2001;Jeong and Zollinger 2004;Yu et al 2004;Rao and Roesler 2005).…”