Effective thermal conductivity of foam concretes: Homogenization schemes vs experimental data and FEM simulations

Abstract

This paper focuses on the prediction of thermal conductivity of foam concretes. Various analytical forms for their effective thermal conductivity according to their porosity p (air voids volume) have been first derived based on five well-known Mean-Field Homogenization (MFH) schemes. These predictions were found to be very close for low porosities but move away gradually with increasing porosity. Thus, in order to determine the best homogenization scheme predicting the effective thermal conductivity of foam concretes, MFH predictions were confronted with experimental data obtained on nineteen foam concretes and also with numerical results obtained from 3d Finite Element Method (FEM) simulations conducted on an idealized foam concrete. These comparisons have shown that the normalized effective thermal conductivity of foam concrete is closely framed by the power law (1- p)3/2 given by the Differential scheme and by the hyperbolic law (1- p)/(1+ p/2) given by the Mori-Tanaka scheme.