Effect of fly ash composition and component quantities on the gamma radiation shielding properties of geopolymer

Fly ashes from different sources, and geopolymers where fly ash is a major component, were analyzed for their gamma radiation attenuating capabilities. The different fly ashes and geopolymers containing fly ashes were assessed for linear attenuation coefficients at energies associated with Co-60 decay. Additionally, a design of experiments was employed to modify a fly ash-based geopolymer formulation to maximize attenuation by changing the quantities of components used in the formulation. The test results show that, despite coming from different sources and having different elemental compositions, differences between class C fly ashes provide marginal differences in linear attenuation coefficient relative to changing aggregate quantity, aggregate composition, and alkalinity. This led to the development of a heavyweight geopolymer through aggregate replacement, where fly ash does not need to be specifically sourced.