Heat and moisture exchanges between building envelope and its interior ambience are related and continued. The current state of art of the hygrothermal interactions modeling between envelope and ambience of building calls upon to dynamic simulation tools where the coupling of heat and mass transfers are generally not considered.In this work, a hygrothermal transfer model in multilayer walls (HAM) is dynamically coupled to a thermal building model (BES). The Coupling concerns the implementation of a co-simulation between COMSOL Multiphysics©, a simulation tool in finite element for hygrothermique transfer through the envelope, and TRNSYS, a thermal simulation tool for building and dynamical systems. The HAM-BES coupling efficiency was verified by carrying out an experimental validation performed in the framework of Annex 41 of the International Energy Agency. Subsequently, a case study is conducted in order to evaluate the effect of taking into account the 1D and 2D hygrothermal transfer modeling in the envelope on the global thermal and hydric behaviors of the building. Results confirm the direct impact of modeling the coupled heat, air and moisture transfer through the envelope on the overall hygrothermal behavior of buildings

This study reports the combined effects of fly ashes, hemp fibers, and shives on the strength performance of modified mortars. Fly ashes are first processed using high-intensity mechanical milling. Natural fibers are observed using X-ray microtomography to reveal the microstructural arrangement. Preliminary formulations are attempted with different proportions of hemp fibers and shives up to 4%. X-ray diffraction, infrared, and thermal gravimetric analysis (TGA) methods are used to reveal the main structural changes in modified cement pastes. Workability and strength characteristics of various formulations are evaluated for ranking. The best performing modified mortars are selected based on their strength performance to formulate the mix proportions of milled fly ash and cement mortar. The experimental results demonstrate the beneficial effect of adding hemp fibers with shiv to achieve acceptable workability. In addition, it was found that the optimal hemp content in modified mortar was 3%. This amount minimizes the negative effect of natural additions on mechanical strength. Finally, fly ashes are found to be an efficient leverage to formulate modified mortars exhibiting a strength performance superior to that of the reference mortar.

Porous materials possess a complex structure on a microscopic scale and present strong heterogeneities, which makes their precise study extremely complex. In fact, the macroscopic behavior of these materials is strongly dependent on mechanisms that act to the scale of their components. The present work focus on the development of a macroscopic conductive and convective fluid heat transfer model, with a heat source in the unsaturated porous materials. This model is established by periodic homogenization of energy conservation equations written on a microscopic scale in each phase (solid, liquid and gas). The resulting input parameters formulations of the submodel were explicitly identified. Numerical calculations of the homogenized thermal conductivity tensor are performed on a representative 3-D elementary cell of the porous medium. Finally, a sensitivity study of this tensor depending of the variation of the water content and porosity of the concerned elementary cell has been performed. This sensitivity is required to be considered in simulations to better understand the behavior of building materials and improve the prediction of energy performance.