Influence of Temperature Level on the Properties of C25/30 Concrete Used at Cernavoda NPP Containment

The paper aims to analyze the influence of high temperatures (65°C, 80°C and 100°C), which can result from abnormal operation, on the macro structural properties of concrete (compressive strength, permeability, modulus of elasticity), properties which indicate the concrete durability. To accomplish this goal, C25/30 concrete samples were subjected to thermal treatments for 1 year. The obtained results indicate a more pronounced decrease in compressive strength for samples exposed to thermal stress at 65°C; for the temperature of 100°C, this parameter has increased after applying the thermal treatment. Regarding the modulus of elasticity and the permeability of concrete samples, it is observed that they decrease with increasing of the temperature. However, after applied thermal stress, the studied properties continue to meet the requirements imposed for this class of concrete, indicating that the concrete maintains a high level of durability and fulfils its role of nuclear safety barrier. (author)