The effects of different types of concrete on population doses

To determine the radionuclide concentrations of materials constituting concrete in Japan, measurements have been carried out on the components, namely steel, coarse aggregate, fine aggregate, cement, cement admixture and water. Since the radionuclide concentrations of steel, cement admixture and water are far less than those of other components, only coarse aggregate, fine aggregate and cement were measured. The mean concentrations of K-40, U-238 and Th-232 in the concrete samples cover a wide range from 6.8 to 912.5 (average 505.2) Bq.kg(-1), 2.93 to 86.7 (average 32.3) Bq.kg(-1), and 1.59 to 61.6 (average 25.6) Bq.kg(-1), respectively. The average annual dose at 1 m above an infinite plane surface for the samples studied is calculated as 318 mu Sv.y(-1). These results show that the radionuclide concentrations of components in concrete in Japan are lower than those in other countries. The concentrations showed nearly the same distribution pattern as the intensity of gamma rays from soil and tectonic lines in the various geographical regions.