Mathematical Models of Homogenization for a Rammed Earth Blend Made of Crushed Limestone and Cement in Linear Micro-poro-elasticity

¹ University of Western Australia, School of Design, Perth WA 6009, Australia
² University of Western Australia, School of Civil, Mining and Environmental Engineering, Perth WA 6009 Australia

^a Corresponding author: vittoria.strazzeri@research.uwa.edu.au

Abstract

Rammed earth (RE) designates natural building materials that can contain stabilized or non-stabilized soils or crushed stone blends. RE materials are non-homogenous and their performance depends on their compositions, grain size distributions, porosity, and mode of preparation. This category of building materials has recently been subject of extensive studies, due to the increasing interest in sustainable construction, which have highlighted the potential and limits of its large uptake. Although it has been demonstrated that RE can be treated as multi-component materials [1] a full characterization based on micro-structural considerations is still lacking. Full understanding of the role of porosity in the overall material performance has not been addressed. However, extensive literature [2, 3, 4, 5] is available that can describe the overall mechanical behaviour of similar materials, based on the principle continuum micromechanics. This study applies the Mori-Tanaka homogenization scheme to characterize the linear elastic behaviour of cement-stabilized crushed-limestone-based material by treating it as a porous composite. The composite comprises a solid phase consisting of limestone grains bonded together with hydrated cement bridges and a fluid phases consisting of different families of pores. The microstructure of rammed earth samples has been observed using an optical microscope. The obtained images have been collected and processed to obtain the pore sizes and pore size distribution. Finally, these statistics along with the Mori-Tanaka homogenization scheme have been used to determine the overall elastic properties that depend on a damage parameter enclosing the pore sizes, density, and texture