7. Stress corrosion cracking

7.1 Characteristics of stress corrosion cracking

Prestressed reinforcement is tensioned to between 55% and around 80% of its yield strength, depending on the applicable regulations.

This steel must be placed in a cement-based solid (concrete or grout). However, this protection is sometimes lacking, especially when the grout is poorly injected along the entire length of the reinforcement. Under these conditions, the tensioned steel cracks and eventually breaks.

The mechanisms of metal stress corrosion involve either localized dissolution or hydrogen embrittlement. It is the latter mechanism that applies to non-alloy steel prestressing reinforcement