Hygrothermal and Acoustic Assessment of Earthen Materials

Thanks to their microstructure which allows both exchange of gas with their surrounding environment and internal water vapour sorption phenomena, earthen materials are highly hygroscopic. If no material is used as a barrier or retardant to the diffusion into the envelope between the earth and the indoor environment of a building, they have a great potential to enhance the thermal comfort and to regulate indoor air quality. In addition, even if few studies have been realised on that point, a high acoustic absorption can be anticipated due to their open porous structure. However, notably due to the lack of standardized procedure to measure their performances, these multi-functional capabilities of earthen walls are almost not considered in the design and rehabilitation operations. In that context, in the framework of the RILEM Technical committee TCE 274, this chapter aims at presenting a critical bibliographic review related to the assessment of hygrothermal and acoustic performance of earthen structures. It is a first necessary step in order to define performance-oriented tests to properly assess their hygrothermal and acoustic performances. In particular, the analysis of collected information allowed to underline some consensus on the protocols that should be used to measure some of the key parameters, while the necessity to perform some additional investigations on others was clearly identified.