Natural radioactivity in cements and raw materials used in Albanian cement industry

This study examines the natural radioactivity in cements and raw materials used in cement production industry with the aim to assess the population exposure to the radiation due to their use in dwellings. The results show that the limestone is the principal contributor for the presence of Ra-226 activity concentration in cements. The contribution of aluminosilicate materials, mainly for the presence of K-40 and Th-232, shows high variability mainly due to the possibility of use of different types of raw materials. The activity concentration is found to be higher in Portland cements relative to Portland-limestone cements with values varying from 12.0 to 16.1 Bq kg(-1) for Ra-226, 46.2-51.2 Bq kg(-1) for Th-232 and 133.7-168.8 Bq kg(-1) for K-40. The activity concentration index (ACI), recommended by the Council Directive 2013/59/EURATOM and recently amended in the Albanian legislation, was adopted as a screening tool to assess the radiological hazard due to the use of cements as building materials. The ACI varies from 0.26 to 0.31, which allows us to conclude that potentially these building materials do not pose any significant risk to humans due to their use in dwellings. This conclusion is confirmed by calculating the annual effective dose rate, varying from 0.33 to 0.38 mSv y(-1).