Durability and Radiation Shielding Performance of GGBS- and SF-Modified Mortar under High-Temperature Sulfate Exposure in Arid Environments

A durable and radiation-resistant concrete is crucial for NPPs and other nuclear facilities where radiation exposure is critical. Concrete in arid regions is subjected to elevated temperatures, external sulfate exposure, and aggressive chemical attacks. The study investigates the impact of elevated temperatures on concrete durability and radiation shielding properties, along with chemical sulfate exposures. To achieve this, experiments were conducted to assess mechanical properties, including compressive and flexural strength. Non-destructive techniques like resistivity and UPV were used as indicators for degradation of mortars. The attenuation coefficient was determined by utilizing Cs-137 and Co-60 radioactive sources along with a HPGe detector. The results showed a correlation between sulfate-induced deterioration and changes in both mechanical performance and shielding efficiency, with apparent variations depending on the sulfate solution type and exposure conditions. At photon energy of 1173 keV, the results indicated that samples with SF and GGBS exhibited increases in attenuation coefficient of approximately 23%, 15%, and 4% after exposure to Na₂SO₄, MgSO₄, and Na₂SO₄ + NaCl, respectively, at 50°C for 120 days. While Ordinary samples showed a reduction of approximately 7%, 10% and 10% under the same conditions. This research supports advanced concrete design for durable nuclear infrastructure applications.