Numerical Tool for the Evaluation of the Hygrothermal Performance of a Hemp-Lime Concrete

Hemp concrete is a non-loadbearing material used as filling material to form the building envelope. Hemp concrete is an hygroscopic bio-material characterized by a strong hysteretic hydric behavior and interesting thermal conductivity. A numerical tool able to model the hysteretic behavior of the hemp concrete sorption process is presented. The implementation of a suited hysteresis model in a heat and moisture transfer model allow evaluating and discussing the influence of this phenomenon in the transient hygrothermal response of hemp concrete to hydric loadings. The governing system of strongly coupled unsteady differential equations is implemented in Matlab with a finite differences method. Numerical transient hygrothermal responses of hemp concrete submitted to cyclic hydric isothermal loadings are then produced and compared with experimental results.