Numerical approach to predict zero-stress temperature in concrete pavements

Abstract

Zero-stress temperature (ZST), defined as an inelastic indicator for the behavior of concrete elements in early-age, is one of the critical factors affecting the behavior and performance of concrete pavements. However, available and reliable methods for selecting this parameter are still limited. In this paper, a numerical approach to predict ZST in concrete pavement slabs was proposed. A one-dimensional (1D) finite-difference method to predict the temperature distribution in a hardening concrete slab was developed. To calculate the early-age stress in concrete slab subjected to the environmental loads, a two-dimensional (2D) finite-element analysis was also developed. The results of the temperature prediction obtained from the 1D finite-difference method were used and incorporated in the calculating of the early-age concrete stress to establish ZST. The results of ZST obtained from the proposed numerical model showed a good agreement compared with the field experiments. Using the proposed model, the sensitivity analysis of the ZST showed that the construction seasons, concrete placement times, concrete mix proportions, and pavement thicknesses have significant effects on ZST. The proposed numerical model is helpful and useful to predict ZST in concrete pavement slabs for given environmental conditions, concrete placement time, concrete mixture, and slab geometry.