What is 'breakout' in concrete repair?

Breakout is the mechanical removal of defective concrete. It is the noisy, dusty first step of repair. We use percussive breakers or hydro-demolition to remove spalled and carbonated concrete. Crucially, we must break out *behind* the rebar (undercutting) to ensure the repair material fully encapsulates the steel. Stopping at the rebar surface is a common mistake that leads to failure.