Natural Radioactivity and Hazard Level Assessment of Cements and Cement Raw Materials

Abstract

Cement is a composite material and it consists of different raw materials. The raw materials which are used in the cement production industry are commonly obtained from rocks such as limestone, gypsum, clay, and iron ore. In addition, the cement raw materials may also include natural radionuclides such as 226Ra, 232Th, and 40K, which may have an adverse effect on human health. Hence, determination of natural radioactivity level is very important for human health safety. In this study, natural activity concentrations of 226Ra, 232Th, and 40K are investigated in cement and cement raw materials in Turkey as a case study. In addition, eight different radiological parameters and indices were calculated from activity concentrations. The natural radioactivity due to the presence of 226Ra, 232Th, and 40K was measured using the gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226Ra, 232Th, and 40K in the raw materials were 38.14, 92.66, and 636.63 Bq kg−1, respectively, with higher activity concentrations in coal for 226Ra and trass for 232Th and 40K. Mean activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) in cement samples were found as 34.26, 58.2, and 512, respectively. The results showed that coal and fly ash are the principal contributors for the presence of 226Ra activity concentration, trass and iron ore materials for the presence of 232Th, and clay and trass raw materials for the presence of 40K in cements.