Prediction of radiation changes in concrete and mortars under the influence of gamma radiation

The present research was carried out due to the insufficient study of the effect of gamma radiation on concrete and mortar. The research took into account the availability of developed and experimentally tested methods for the analytical determination of radiation, thermal, and radiation-thermal changes in concrete and its components under neutron irradiation and heating, as well as radiation changes in the aggregates and hardened cement paste (HCP) under the influence of gamma radiation. The aim of the work was to establish the possibility of using these existing analytical methods to predict radiation changes in concrete and mortar under the influence of gamma radiation. In this case, the existing experimental results of the influence of gamma irradiation on 7 different concretes and 11 cement mortars were used. The studies performed have shown the possibility of using existing analytical methods to predict radiation changes in the dimensions of concrete under the influence of gamma radiation. The results of the studies of predicting radiation changes in the strength of concrete and mortars under the action of gamma radiation showed significant differences between the calculated and experimental changes when using the existing analytical methods applied under neutron irradiation and heating without their correction. It is assumed that this is due to differences in the processes of acceleration of hydration and carbonization of HCP under the action of gamma radiation under neutron irradiation-heating and under gamma irradiation. It is proposed to take into account these differences in the values of one of the parameters of the method for analytical determination of strength changes in early age HCP and to introduce an additional correction factor that takes into account the effect of aragonite and vaterite formation during carbonization of mature HCP under the action of gamma radiation. The values of this parameter and its dependence on the change in the volume of early age HCP under the action of gamma radiation are established. The values of the additional coefficient taking into account the effect of aragonite and vaterite formation for the considered mature concretes and its dependence on the absorbed dose and the estimated amount of carbonates are determined. It is shown that by using the adjusted parameter for early age concrete and an additional coefficient for mature concrete, the existing analytical methods can be used to predict radiation-induced changes in the strength of concrete and cement mortars under the influence of gamma radiation.