Radiation changes of concrete aggregates under the influence of gamma radiation
The work (in connection with the small study of the effects of gamma ray on concretes and their components) contains the results of calculation and analysis of radiation changes of concrete aggregates under the influence of gamma ray on the basis of analytical methods developed previously during the neutron irradiation process. The possibility of using these analytical methods in the case of exposure to gamma ray was substantiated. The relationship of the absorbed doses of gamma ray of different energies with the number of atoms displaced during irradiation was established. There is an assessment of radiation changes in the volume and strength of the main types of rocks - aggregates of concrete (igneous, sedimentary rocks and ores) under the influence of gamma ray with an average energy of 2 MeV and 5 MeV after irradiation to absorbed doses of 105 to 1011 Gy at 30 °C, 100 °C and 300 °C. For this, from the beginning, the radiation changes of the main rock-forming minerals were calculated, and on the ground of them, the radiation changes of rocks of concrete aggregates were calculated. It has been established that noticeable radiation changes of considered minerals and rock aggregates will occur only at absorbed doses of gamma ray of more than 1ꞏ109–1ꞏ1010 Gy of gamma rays with an energy of 5 MeV and of 3ꞏ109–3ꞏ1010 Gy for gamma rays with an energy of 2 MeV. The number of radiation changes grows with a rise in the absorbed dose and significantly decrease with an increase in the irradiation temperature for silicate class minerals and silicate rocks. The greatest radiation changes under the influence of gamma ray at 30 °C are observed in silicate minerals and rocks, especially olivine pyroxenes, hornblende, dunite, peridotite, pyroxenite, and gabbro. Moreover, even with an absorbed dose of gamma ray of 1011 Gy, the radiation changes are not large (increase in volume is not more than 0.36 %, decrease in strength is not more than 8.7 %). As the temperature increases, the ratio in the magnitude of radiation changes of different materials changes.