The principal reason concrete bridges deteriorate is that the reinforcement is damaged by chloride-induced corrosion. Effective maintenance, for the most part, involves activities designed to keep chlorides away from the reinforcement. Six maintenance activities help accomplish this goal: flushing debris and chlorides from decks and pier caps annually, repairing and sealing joints, sealing cracks, patching potholes, replacing the membrane if replacing an asphalt overlay, and installing low-permeability overlays.