Radiological characterization of anhydrous/hydrated cements and geopolymers

•Activity concentration in hydrated blended and non-blended cements is first time studied.•Radioactivity in alkaline cements or geopolymers is also first time investigated.•Radioactivity of blended cements with industrial wastes may be optimised controlling their final dosage. The aim of this study has been to determine the activity concentrations of 40K and radionuclides from the 238U and 232Th 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 28days 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 40K in geopolymers pointing to an increase of this isotope in the sodium compounds used for its activation.