Application of thermo-hydro-chemo-mechanical model for early age behaviour of concrete to experimental massive reinforced structures with strain–restraining system

Abstract

This paper presents the application of a thermo-hydro-chemo-mechanical (THCM) model to the design of actual massive structures with a system to restrain the strain at early age (thermal strains and autogenous shrinkage). The experimental campaign was performed in the French national project CEOS.fr. The modelling of early-age behaviour of reinforced concrete is first based on a hydration model, which is able to reproduce the variations of temperature, water content and mechanical properties according to hydration. Then a non-linear mechanical model is used (combining creep and damage models, both adapted to hardening concrete). The comparison between numerical results (obtained with a calculation time of around 12 h on an ordinary computer) shows that the models are able to reproduce the early-age behaviour of restrained reinforcement concrete structures (in terms of strains, global forces and crack patterns). Using steel-concrete interface elements (adapted to early age), the models are also able to reproduce the influence of reinforcement on cracking.

Keywords:

• early age
• thermal strain
• cracking
• reinforced concrete
• massive structures

Acknowledgements

The investigations and results reported here were supported by the French national programme CEOS.fr and the French National Research Agency (ANR) under the MEFISTO research programme (control of cracking in concrete structures/grant VD08_323065). We are also grateful to CEA/DEN/DM2S/SEMT for providing the finite element code CASTEM.