Degradation of concrete may happen due to corrosion, structural damage, water penetration or many other reasons. Normet, and TAM before that, have spent decades developing concrete repair solutions to return the concrete back to its original condition or better. There are a number of different repair solutions from Normet
Cement within a concrete mix doesn't contain any natural bonding agents. When concrete is added to an existing layer of concrete, steel or iron, the concrete will sit as a separate layer and won't be joined or bonded to the existing material. This will not produce a strong repair so the existing layer needs treating with a bonding agent as a primer.