As DB said, the old tower has concrete cancer. It was never painted when constructed thereby allowing the concrete to absorb atmospheric carbon dioxide which eventually reaches the steel rods causing the cancer. The cancer was treated in the mid 90s and the tower painted.
What sort of BS is this? Concrete cancer...concrete absorbs Co2 and degrades in a few years...!?!?!?!
You dont need to paint concrete, look how many structures, walls and bridges have been built and lasted.
If you provide the minimum cover over the bars, there will not be any issues when exposed. Look at the concrete poured on water fronts, and in the water...see any paint?