Multi-scales Characterization of the Early-age Creep of Concrete

International audienceConcrete is a heterogeneous material that develops delayed strains under a constant load. These deformations are related to micromechanisms which occur in its microstructure. To model this behaviour a new numerical multi-scales method is suggested. Based on a method for the calculation of the effective response for a non-aging material, an extension to aging materials has been developed. This method operates directly in space-time and avoids the difficulties of Laplace Carson transform inversion. The delayed strains are calculated in a representative elementary volume thanks to classical finite elements method which allows determining the components of the creep compliance tensor. First of all, calculations have been performed for an uni-axial loading to model the creep strain at different scales in order to give the visco-elastic property of calcium silicate hydrates. Then, the evolution of the microstructure with age has been considered to model the creep at early-ages of concrete