A finite element model development for simulation of the impact of slab thickness, joints, and membranes on indoor radon concentration

The focus of this study is broadly to define the physics involved in radon generation and transport through the soil and other materials using different parameter-estimation tools from the literature. The effect of moisture in the soil and radon transport via water in the pore space was accounted for with the application of a porosity correction coefficient. A 2D finite element model is created, which reproduces the diffusion and advection mechanisms resulting from specified boundary conditions. A comparison between the model and several analytical and numerical solutions obtained from the literature and field studies validates the model. Finally, the results demonstrate that the model can predict radon entry through different building boundary conditions, such as concrete slabs with or without joints, variable slab thicknesses and diffusion coefficients, and the use of several radon barrier membranes. Cracks in the concrete or the radon barrier membrane have been studied to understand how indoor concentration is affected by these issues. - Highlights: • A numerical 2D model for radon transport in soils is proposed. • The model considers both the diffusive and advective mechanisms. • Introducing a correction factor accounts for the aqueous phase. • A comparison is made between the model and other measured and calculated studies. • The finite element model is applied to different case studies.