Abstract

The aim of this study has been to determine the activity concentrations of K-40 and radionuclides from the U-238 and Th-232 decay series in commercial cements, some industrial wastes and geopolymers (also called alkaline cements) and to calculate their activity concentration levels after the cement hydration/activation at 28 days to ascertain the effect of these processes on their final activity concentrations. The highest activity concentration levels of radionuclides from uranium and thorium series have been obtained in the fly ashes, slags and calcium aluminate cement. When a blend among industrial wastes and cement is realised, the radionuclides activity concentration are calculated on the grounds of their percentages in the blend material and tested by its experimental measurement. Once the hydrated/activated cements and geopolymers have been obtained, a proportional decrease to the percentage of added water is observed in the radionuclides activity concentration for the hydrated cements and no-correlation in the case of K-40 in geopolymers pointirig to an increase of this isotope in the sodium compounds used for its activation. (C) 2015 Elsevier Ltd. All rights reserved.