This paper reports the effect of coating the concrete surfaces with mortar of high nitrite content on corrosion protection of reinforcing bars within concrete containing chlorides. Accelerated corrosion tests in a glass house and outdoor exposure tests were conducted over a period of 5 years. Specimens were made with using concrete containing 0.3-4.0 kg/m3 chlorides. Reinforcing bars were embedded with different cover depths in the specimens, the surfaces of which were coated with mortar of high nitrite content. The measurement of the half-cell potentials indicated that, starting from those with thin cover, the corrosion?inhibiting environment gradually surrounds the bars in the specimens as the nitrite ions permeate the concrete. Weight losses by corrosion of the reinforcing bars were embedded in the specimens with mortal of high nitrite content were less than those of specimens uncoated or coated with polymer cement mortar. It was confirmed that the mortar coating with high nitrite content is effective in protecting reinforcing bars from corrosion in concrete in which chloride ions have already penetrated.
