Due to its ecological interest and large availability, a renewed attention is paid to earth as building material. Indeed, raw earth consumes CO2 only during its processing and transportation, and it provides a natural hygrothermal comfort. However, its mechanical properties are highly linked to its composition, which causes an important variability of performances. That is why any soil has to be characterized before being used as a building material. The aim of this study is to propose a model able to predict the hydromechanical behavior of a reconstituted soil according to its composition. As earth is a heterogeneous material, the model is based on homogenization procedures. The sand is considered as spherical inclusions inside a clay matrix. The particularity of the model stands to consider both positive and negative effects of volume variation and mechanical properties of clay under hydric variations. The model parameters are determined according to an original experimental campaign, which is conducted on various mixes of a single type of clay (kaolinite) and of sand, and water. The experimental study provides some mechanical properties of the mixes versus water content and sand content to test the ability of the homogenization model to assess the main properties of this material.
Experimental study of thermal properties of a new ecological building material based on peanut shells and plaster
