Development and hygric and thermal characterization of hemp-clay composite

Abstract

This study investigates the use of clay as binder in hemp composite and compares hemp–clay composite to hemp–lime concrete. The clay is produced from washing mud from gravels production site. Two clay drying temperature are used. The thermal properties are measured with a hot wire method and the hygric characterization is based on the measurement of Moisture Buffer Value. Performances obtained on clay blocks, hemp–clay composite and hemp–lime composite are compared. The results show that the two clay drying temperatures do not impact on the thermal conductivity nor on the moisture buffer value of clay blocks. Hygric and thermal performances of hemp–clay and hemp–lime composites with the same density are close. These materials act as excellent hygric regulators. Performances measured separately on hemp and clay underline an interesting synergetic effect in the case of hemp–clay composite leading to a higher ability to the moisture buffering. Such material can be advantageously used in buildings to moderate indoor humidity variations.