DETERMINATION OF NATURAL RADIOACTIVITY LEVELS OF CONCRETE CORE AND CEMENTS IN ESKISEHIR AREA

People spend large part of their daily lives inside the building where they are exposed to environmental factors natural radioactivity. Cement is a building material of reinforced concrete structures; therefore, determination of the natural radiation level of cement is important for human health. Natural radio activity levels of raw material sources affect radioactivity level of cement which in turn affect the radioactivity level of concrete in structures. High amount of natural radioactivity can be expected in thorium-rich soils such as Eskisehir, Turkey. In this study, fifteen concrete core samples from Eskisehir, and five cement samples collected from Bilecik-Eskisehir-Ankara area. The levels of natural radioactivity (Ra-226, Th-232, and K-40) were measured using gamma-ray spectrometry, and some of the radiological parameters were calculated. The mean activity concentrations of Ra-226, Th-232, and K-40 were 13.2, 15.4, and 212.6 Bq kg(-1) in concrete core samples, and 30.6, 21.3, and 247.2 Bq kg(-1) in cement, respectively. The mean radium equivalent activities (Ra-eq) were calculated as 54.5 and 80.2 Bq kg(-1) for concrete and cement samples, respectively. All Raeq values in the studied samples were found to be lower than the criterion limit of 370 Bq kg(-1). The mean Representative Level Index (RLI) values of concrete and cement samples were lower than the upper limit for RLI but higher than worldwide mean values. According to RLI results, concrete and cement can be considered as non-harmful to human.