Study on radon mitigation performance of building foundations with adsorption layers

Radon, a primary indoor radioactive contaminant, migrates through building foundations and poses radiation hazards to indoor living environments. To mitigate indoor radon pollution, this paper systematically investigates the adsorption-seepage synergistic mechanism of radon mitigation in building foundations by constructing an adsorption layer. This study adopts the Activated Carbon Purification Closed-Loop Method (ACPCM) to measure the radon exhalation rate of the experimental column, and establishes a geometric model of building foundations using Computational Fluid Dynamics (CFD) to evaluate the radon mitigation performance of foundations with adsorption layers under varied parameters and crack scenarios. The results show that as the adsorption coefficient of the adsorption layer rises, the slab radon exhalation-rate declines gradually, while porosity variations show a growing influence on radon exhalation of the slab. On this basis, a calculation model for the radon mitigation rate is established. Comparative analysis indicates that slab radon exhalation decreases as the sump pressure differential increases, with negative pressure outperforming positive pressure; furthermore, the adsorption-seepage synergistic method is superior to the traditional soil depressurization technique. In addition, concrete cracks impair the synergistic radon mitigation performance; wider cracks and those closer to radon sumps result in greater performance attenuation. The research findings provide new insights for the high-efficiency radon prevention and mitigation design of residential and public building foundations.