Influence of low elevated temperature on the mechanical behavior of steel rebars and prestressing wires in nuclear containment structures

- Between 20-140 °C, tensile behavior for rebars and wires is little affected.
- Between 20-140 °C, bond between concrete and rebars may decrease strongly.
- At low elevated temperature levels, relaxation rates increase drastically.
- The initial load ratio has also a strong influence on relaxation.

This paper investigates the influence of a low elevated temperature on the mechanical behavior of steel B500B rebars and T15.2 prestressing wires in nuclear containment structures. Tensile tests were carried out to evaluate the evolution of mechanical properties during heating. The bond between concrete and rebars was also studied and relaxation tests on prestressing wires have been done. Between 20 °C and 140 °C, the mechanical behavior of rebars and tendons exhibited no major deteriorations. However, a high decrease of the ultimate bond was observed for pull-out tests. Concerning relaxation tests, the temperature tends to significantly increase the relaxation rate.