Experimental study of the hygrothermal behaviour of hemp shives-based precast blocks at material and wall scales

Abstract

This work aims to characterize the hygrothermal behavior of precast blocks made of hemp shiv aggregates and of a pozzolanic binder. The first part of the paper consists in the determination of basic hygrothermal properties of hemp concrete at material scale: thermal conductivity, thermal effusivity, vapor sorption isotherm, and water vapor permeability were assessed. The second part aims to develop a new tool allowing hygrothermal solicitation of a whole wall made of hemp concrete blocks sealed with a pozzolanic mortar. We used two climatic chambers to study the response of the wall under constant and sinusoidal variations of temperature and relative humidity of the ambient air. This work revealed the good insulation capacity of the studied precast blocks and their ability to regulate the relative humidity of indoor air. It allowed the development of a new experimental tool for the study of hygrothermal behavior of hemp concrete masonry wall under constant and sinusoidal solicitations.