Influence of Soil Grading on the Hygro-Mechanical Properties of Hyper-Compacted Earth for Masonry Construction

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 evaluatedby immersiontests. All experi-ments 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 af-fects 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 hygrosco-picityof the material also indicates that raw earth bricks can regulate ambient conditions in-side dwellings and therefore reduce carbon emissions and energy consumption due to air-conditioning installations