The effect of different mix proportions on the hygrothermal performance of hempcrete in the Canadian context

Hempcrete is a light composite bio-based envelope plus insulation material with lime as binding agent and hemp as a renewable raw material from agriculture. The main qualities of hempcrete are hygrothermal behavior and low environmental impact. There is currently lack of clear cross-industry standards for hempcrete; however, extensive research, laboratory experiments and literature reviews are ongoing. The primary aim of this study was to understand the impact of different mixes on the performance of hempcrete and to establish hygrothermal behavior of a hempcrete wall in the Canadian context (by measuring dry density and some other hygroscopic parameters for 3 different mixes) as well as to define the required minimum thickness for a code compliant wall (as per OBC requirements) based on the most reliable reference R values. Based on the material values acquired from the tests and references, simulations for 2 types of wall assemblies and series of sensitivity analysis were carried out in WUFI software. Finally, further research on hygrothermal performance of hempcrete wall (using Canada grown hemp) was recommended to carry out by measuring thermal conductivity in various mean temperatures.