Final answer:
Steel is protected against corrosion, fire, and structural failure through a process known as galvanization, where a zinc coating is applied to create a protective barrier. Galvanized steel benefits from cathodic protection, even if the zinc layer is damaged, as it continues to prevent steel corrosion by sacrificing itself.
Step-by-step explanation:
The amount of protective coating or galvanization applied to steel is what protects it against corrosion, fire, and breaking out from the concrete. This process usually involves coating the steel with a layer of zinc. The zinc acts as a barrier to moisture and oxygen, which are both catalysts for the corrosion process.
Galvanized steel uses zinc as a protective layer because zinc is more easily oxidized than steel, which means it will corrode first, offering what is known as cathodic protection. Even if the zinc layer is damaged, it continues to protect the underlying steel by sacrificially corroding in place of the steel. This principle of using a more reactive metal to protect a less reactive one is fundamental to stopping corrosion and is a widely used method in the construction and manufacturing industries, safeguarding structures and items such as bridges, automobiles, and even household objects like garbage cans and nails.