The influence of building material structure on radon emanation

Abstract

In this work, the radon emanation coefficients for selected building materials that are most often used in Serbia for covering floor surfaces (concrete, concrete screed, granite, glazed ceramic tiles, marble, roofing tile, and terrazzo tile) were determined, and the influence of the material structure on their values. The concentration of 226Ra activity in the samples was determined using the gamma spectrometry method. Radon emanation was measured with the RAD7 device. The porosity of the samples was tested using mercury intrusion porosimetry and water absorption methods, and the structural analysis was performed using X-ray diffraction analysis and X-ray fluorescence analysis. The measured values ​​of 226Ra activity concentrations were in the range (4.93 – 298) Bq kg-1, and the estimated values ​​of the radon emanation coefficients were in the range (0.55 – 6.05) %. The obtained results indicate that the chemical and mineralogical composition, method of production, and the 226Ra activity concentration have an influence on the emanation of radon from the material. No significant correlation was found between the radon emanation coefficient and the open porosity of the material, most likely due to the inhomogeneous presence of pores of different dimensions in the materials. It was established that the total value of the emanation coefficient depends on the emanation coefficient for pores ≤100 μm in size.

Indoor Radon: Sources, Transport Mechanisms and Influencing Parameters

“…Furthermore, some works showed the emanation coefficient does not depend only on the porosity, but on the dimensions of pores as well (e.g., [101,105]). The mesopores (i.e., smaller than 100 nm) were recognized to be associated with high radon emanation coefficient [106].…”

“…The general approach resulting from the literature is to avoid using the porosity as proxy of the radon emanation coefficient when comparing different types of building materials [105]. Only when discussing the difference in the radon emanation coefficient of materials of the same typology, porosity and pore specific surface are reliable proxies of the emanation coefficient [100].…”