Determining the appropriate ratio of fly ash as cement replacement in concrete and evaluating the radiation dose of the fly ash concrete

This study uses fly ash (FA) as a cement replacement in concrete and evaluates the radiological safety of this concrete sample. Different fly ash mixing ratios were investigated and found that with a mixing ratio of 35%, the compressive strength of FA concrete is the highest (from 38 to 48 MPa). Next, we evaluate the radiation safety of the FA concrete by analyzing the isotopes ²²⁶Ra, ²³²Th, and ⁴⁰K using two low-background gamma spectrometers. The obtained results showed that the use of FA in concrete production is entirely feasible as it meets both construction and radiation safety-related requirements.