Upscaling the elastic stiffness of foam concrete as a three-phase composite material

M. Ben Youssef (1) , F. Lavergne (2) , Karam Sab (3) , K. Miled (1) , J. Neji (1)

1 ENIT - Ecole Nationale d'Ingénieurs de Tunis
2 Cerema Equipe-projet DIMA - Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet DIMA
3 multi-échelle - Modélisation et expérimentation multi-échelle pour les solides hétérogènes

The stiffness of foam concrete depends primarily on the added porosity. Nevertheless, by performing 3D elastic numerical simulations on artificial unit cells in the frame of periodic homogenization, it is shown that describing foam concrete as a porous material is not sufficient to explain the experimental measurements of the Young modulus for added porosity higher than 40%. Indeed, introducing sand as a third phase enables to recover accurate estimates of the Young Modulus. Furthermore, for highly porous concrete foams, it is shown that the stress concentrates in thin members deprived of stiff sand particles, thus leading to a softer overall stiffness.

Mots clés: foam concrete; numerical simulations; Young modulus; microstructure; homogenization

Domaines: Mécanique des matériaux [physics.class-ph]; Génie civil

M. Ben Youssef, F. Lavergne, Karam Sab, K. Miled, J. Neji. Upscaling the elastic stiffness of foam concrete as a three-phase composite material. Cement and Concrete Research, 2018, 110, pp.13-23. ⟨10.1016/j.cemconres.2018.04.021⟩. ⟨hal-01789840⟩