The influence of pinholes in waterproofing materials on the value of the radon diffusion coefficient

This article focuses on an experimental study of the influence of imperfections on the value of the radon diffusion coefficient of various waterproofing materials. Microscopic holes were made by a thin tip or by a micro-drill bit to imitate the real damage that can be incurred during construction. To determine the change in the radon diffusion coefficient, each waterproofing material was measured five times. The first measurement was performed on undamaged samples, while the following measurements were performed on samples with one, two, four and eight pinholes. The radon diffusion coefficient was measured under nonstationary conditions, because homemade radon sources with a slow rate of radon emanation were used. The radon diffusion coefficients identified in the study were compared according to the thickness of the material and the number and the size of the pinholes. The exact shape and size of the imperfections were documented by an electron microscope. (authors)