2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
With a variety of forms, raw earth construction has long historical process in human civilization. As an ancient building material, it raises today a huge interest of architects and engineers considering its low ecological impact and its thermo-hygro-mechanical performances. Nevertheless, as far as raw earth is a heterogenous and unsaturated material, then considered as a multiphase soil (solid matrix, water and air) this material has a multi-physical property which still raises a complexity of proposing laboratory protocols to assess its standard performances. The aim of this paper is to sum up the principal knowledge about raw earth as building material. The complexity of its multi-physical behavior introduces one key parameter: the liquid degree of saturation. The moisture content mainly controls the thermo-hygro-hydro-mechanical behavior of raw earth and therefore its durability. But, in cold regions, the cyclic effects of water freezing and ice thawing on earthen houses cause an extreme moistening which represent a major risk of frost damage. This paper concludes with some theoretical approaches to model frost/thaw actions in an unsaturated soil.