Multi-scale investigation of the effect of γ irradiations on the mechanical properties of cementitious materials

We studied the effects of low doses of gamma radiations on physical and hydro-thermo-mechanical behavior of concrete in the context of radioactive wastes storage. Mortar samples were irradiated with a Cs-137 gamma source to perform three-points bending, compression and physical analysis. Dry, humid and carbonated mortars and dry and carbonated cement pastes were used. The structural and mineralogical modifications at microscopic scale due to irradiations are determined. The results show an important drop of mechanical strengths except in the case of carbonated samples. Thus, the hydrated phases of the mortar/cement are likely involved in the degradation of the mechanical properties.