Finite‐Element Modeling of Deformation and Cracking in Early‐Age Concrete

Abstract

The main nonlinear phenomena that govern the deformational behavior of early‐age concrete are the evolution of the stiffness properties, the development of thermal strains, creep, and cracking. A general approach for numerically simulating this type of behavior is presented. The thermomechanical problem is decoupled such that first a thermal analysis is carried out and then a stress calculation is performed. An interface program is used to map the results from the thermal analysis onto the input data required for the stress analysis. A brief review of the relations for the thermal‐stress analysis is given, followed by a more elaborate treatment of the algorithm used for the combination of thermal strains, creep, and smeared cracking. To properly accommodate these effects in a finite‐element analysis, a smeared‐crack model is used that is rooted in a decomposition of the strain increments. The emphasis is on the general approach for properly and efficiently handling these phenomena. A special case, namely a power‐type creep law, is elaborated. It is shown that this relationship reasonably fits experimental data. A detailed description of an example calculation that demonstrates the potential of the numerical simulation strategy follows.