Effect of Nonlinear Temperature Gradient on Curling Stress in Concrete Pavements

Abstract

Temperature and moisture gradients can lead to significant tensile stresses at the slab top and bottom. Current techniques for assessing the internal stresses due to such gradients are based on the assumption that temperature and moisture distributions through the slab thickness are linear. However, the actual distributions of such gradients have been found to be highly nonlinear. A new closed form solution technique for calculating the stresses in a pavement slab due to nonlinear gradients is introduced. The analysis is separated into two parts. In the first, an expression is presented for calculating the self-equilibrated stresses within a cross section due to internal restraint (i.e., satisfying equilibrium conditions and continuity of the strain field within the cross section). These stresses are independent of slab dimensions and boundary conditions. In the second, the stresses due to external restraint (i.e., self-weight and subgrade reaction) are calculated using an equivalent linear temperature gradient obtained from the first part and existing closed form solutions by Westergaard or Bradbury. The solution to this step includes slab length and boundary conditions. Total internal stresses due to nonlinear gradients are obtained by using the superposition principle. The methodology has been applied to field data from two studies in which the temperature profiles were recorded throughout a 24-hr period. Linear gradient solution methods cannot accurately predict the curling stresses in concrete pavements. This is especially pronounced during nighttime and early morning hours, during which nonlinear analysis predicts tensile stress in both the slab bottom and top before the application of any traffic loading.

Influence of vehicular positions and thermal effects on structural behaviour of concrete pavement

“…However, Choubane and Tia [1995] showed that temperature distribution in pavement depth is nonlinear. Mohamed and Hansen [1997] developed an analytical method to estimate the induced tensile stress in concrete pavements subjected to a nonlinear temperature gradients. The concept of equivalent temperature distributions was then employed in concrete pavement analysis based on the plate theory [Ioannides and Khazanovich 1998].…”

Factors influencing stresses and movements in continuously reinforced concrete pavements – A review

“…The lift-off in concrete slabs has been investigated by many researchers so far, by taking into consideration effects of curling and warping, together and separately (Westergaard, 1927;Tang et al, 1993;Bari & Zollinger, 2016;Jeong & Zollinger, 2006;Jeong et al, 2006;Bissonnette et al, 2007;Mohamed & Hansen, 1997;Rao & Roesler, 2005;Yu et al, 1998;Rao et al, 2001). A pioneering work has been done by Westergaard (1927) on the thermal stress field analysis in rigid slabs due to their curling.…”

Horizontal Cracking in Continuously Reinforced Concrete Pavements

“…Based on experimental and numerical study results, a comprehensive factorial experiment was developed, and the HC potential was assessed for the factors related to the materials, design and construction of CRCP. 3 …”

“…from the surface. A nonlinear temperature gradient with a 3rd degree parabola was assumed [3]. The temperature difference of 21 ˚F between the top and bottom of the slab was applied as an environmental loading.…”

“…Figure 6.1 illustrates the decomposition of a general nonlinear temperature gradient into three equivalent components: uniform, linear, and nonlinear [5]. A parabola of 3rd degree was assumed for the temperature profile along the depth of the slab [3]. The temperature difference of 21 °F was assumed between the top and bottom of the slab.…”