Investigating Hemp Concrete Mechanical Properties Variability Due to Hemp Particles

Abstract

Nowadays, the use of bio-source and recyclable materials are experiencing considerable success. They include among others, the wood, the bamboos and the innovative concrete in which vegetable origin aggregates are used. In this latter case, several types of aggregates are used like sunflower, hemp particles, etc. Hemp particles are increasingly used thanks to its environmental asset, such as the positive CO₂ balance and its easiness lifecycle management. In construction applications, they have also other advantages like good thermal and acoustic insulation properties. However, its major drawback is related to low mechanical performance. The present work investigates the impact of hemp aggregates on the mechanical properties of hemp concrete. Nine different hemp particles from different origins (country, region, etc.) with varied properties (size, water absorption, etc.) are used in the same conditions (binder, specimen fabrication, etc.). Fabricated specimens were submitted to mechanical compression test, then compressive strength and moduli are analysed. The obtained results show high variability. Hemp particles impact results in a mechanical response with low, medium and high levels of deformation. A factor close to 10 is observed between the minimum and maximum compressive strengths. The performed analyses show that the interaction between the hemp particles and the binder is likely to contribute to the mechanical response. Hence, further investigations taking into account their chemical composition may allow to better understand this interaction impact.