Alessia Cuccurullo1, Domenico Gallipoli1, Agostino Walter Bruno1, Charles Augarde2, Paul Hughes2, Christian La Borderie1
1)  Université de Pau et des Pays de l’Adour (France)
{alessia.cuccurullo, domenico.gallipoli, agostinowalter.bruno, Christian.Laborderie}
2)  Durham University (UK)
{charles.augarde, paul.hughes2}

Keywords: Raw earth material, Hygroscopic behavior, Stiffness, Strength, Durability

Abstract. This paper presents a study, at material scale, of the dependency between particle size distribution and the mechanical, hygroscopic and durability properties of compacted raw (unfired) earth for manufacturing bricks. Stiffness and strength are measured by unconfined compression tests while vapour adsorption/desorption is investigated by moisture buffering tests. In addition, the durability to water erosion is evaluated by immersion tests. All experiments were performed on cylindrical earth samples compacted at a very high pressure (100 MPa) and optimum water content. Results show that the particle size distribution strongly affects the hygro-mechanical behaviour of the material, which suggests that careful selection of the soil mix is necessary to optimize the manufacture of raw earth bricks. The high hygroscopicity of the material also indicates that raw earth bricks can regulate ambient conditions inside dwellings and therefore reduce carbon emissions and energy consumption due to airconditioning installations.