Light earth performances for thermal insulation: application to earth-hemp

Abstract

The present study aims at evaluating the impacts of raw materials variability (earth and hemp) on hempearth performances. This work is performed in the framework of the ECO-TERRA R&D project in collaboration with four French research laboratories, short circuit hemp producers and craftsmen specialized in hemp and earth constructions. This article is focused on the thermal conductivity, and mention preliminary results of the mechanical characterizations. The results are compared to lime-hemp materials, one of the most studied bio-based concrete for thermal insulation in R&D programs. The typical volumetric mass of a dry lime-hemp mixture is about 330 to 400 kg/m3, which corresponds to a thermal conductivity about λ = 0,11 W.m-1.K-1 (measured with hot plates, at 20°C and 50% relative humidity).