Surface treatments for concrete highway bridges

Reinforced concrete is vulnerable to reinforcement corrosion when exposed to chloride de-icing salts. Concrete surfaces exposed to traffic spray or at risk from leaking joints can be protected by surface treatments. This report discusses the function, specification and testing of such surface treatments. Twenty one treatments were applied to sintered glass discs and their rates of water vapour, water and chloride ion transmission measured. Subsequently the performance of five of the treatments was measured on a concrete substrate. In these tests, all the treatments reduced the rates of chloride ion uptake by at least 90 per cent. The sintered glass discs, as used in these experiments, did not adequately model the behaviour of a concrete substrate.