RILEM TC-275 (HDB): Presentation of TC HDB and mechanical performances of hemp concrete of the specimen of the round robin test

Abstract

This study delves into the mechanical performance of hemp concrete – a sustainable construction material – with a focus on how the orientation of the hemp shiv affects its mechanical properties. Employing uniaxial compression testing and advanced Digital Image Correlation (DIC) techniques for surface deformation analysis, the research examines specimens in which the shiv particles are aligned perpendicular and parallel to the load direction. Results indicate significant variability in mechanical behavior – perpendicular specimens demonstrate a clear stiffening phase up to 3% strain before deterioration, whereas parallel specimens lack distinct phases. Moreover, DIC measurements suggest hemp concrete has higher Young's moduli and Poisson's ratios compared to traditional materials, and they underline considerable strain localization, especially at aggregate boundaries in parallel specimens. The DIC analysis provides a deeper understanding of the heterogeneous strain distribution, highlighting the interfacial transition zone's influence on the material's mechanical characteristics. These insights are pivotal for optimizing the use of hemp concrete in sustainable building design.