Electrically conductive metal is melted, preferably by a flame, and is sprayed onto a freshly exposed, pitted surface of a concrete member having iron embedded therein. The sprayed metal, when cooled, forms a metal cover on and interlocked with at least part of the newly exposed surface. The cover and the embedded iron are preferably joined in an electric circuit affording a direct current electromotive force, effectively opposite to that which normally would occur, in order to preclude the deterioration of the contained iron.