Methodological issues for the mechanical characterization of unfired earth bricks

Earth is a traditional building material used through History in many areas around the world. Nowadays, there is also a significant revival of its use because of its ecological value and architectural performance. However, there is still a lack of knowledge about its actual mechanical behavior. This paper is aimed at providing experimental data for the development of consistent methodologies for the characterization of this building material. Compression tests of prismatic, cubic and cylindrical specimens were carried out. The compressive strength, Young modulus and the stress-strain constitutive law are obtained and analyzed. The paper shows that the Unconfined Compression Strength of the material should not be obtained by applying existing correction factors for other materials. The paper also analyzes the meaning and usefulness of different estimates of the Young modulus. Finally, the paper proposes a simplified method for estimating stress-strain relationships from the compressive strength and its corresponding strain of tested samples by using reference normalized curves.