Hard to be precise without more knowledge. Epaufrure is often used in reference to damage caused by knocks, as is spalling though in principle it is a specific kind of damage caused by penetration of chloride ions causing reinforcement to rust and expand, thereby breaking off surface plates of concrete from the inside; it can also be the result of insufficiently dense or sealed concrete and penetration of water which later freezes and breaks off pieces of concrete, again from the inside.

Your client might not want to suggest that his concrete is inferior or that the reinforcement is too close to the surface (whether it is or not) and something that is confined to "mechanical damage" caused by rough handling, say, might be preferable.

Hard to know what is best without fuller context, but "chipped" sounds rather less incriminating - and puts the onus on some intermediary - than "spalled"