  Early age behaviour of concrete is based on complex multi-physical and
multiscale phenomena. The predication of both cracking risk and residual
stresses in hardened concrete structures is still a challenging task. We
propose in this paper a practical method to characterize in the construction
site the material parameters and to identify a macroscopic model from simple
tests. We propose for instance to use a restrained shrinkage ring test to
identify a basic early age creep model based on a simple ageing visco-elastic
Kelvin model. The strain data obtained from this test can be treated through an
early age finite element incremental procedure such that the fitting parameters
of the creep law can be quickly identified. The others properties of concrete
have been measured at different ages (elastic properties, hydration kinetics,
and coefficient of thermal expansion). From the identified early age model, we
computed the temperature rise and the stress development in a non reinforced
concrete stress for nuclear waste. The good agreement between in-situ
measurement and predicted behaviour allowed us to validate our approach.
