Assessment of reinforcement corrosion in a concrete highway tunnel

Artikel i vetenskaplig tidskrift, 2006

This paper presents a case study of the assessment of reinforcement corrosion in concrete highway tunnel structures in Stockholm, Sweden. The tunnel is about 1.6 km long and consists of different types of reinforced concrete aged from12 to 40 years. Due to the use of deicing salts, the concrete structures have been subjected to corrosion damage in different extents. The newly developed rapid technique for corrosion measurement was employed for mapping the corrosion of steel in about 120 monoliths of concrete walls along the tunnel. The technique involves the measurements of corrosion rate, half-cell potential and resistivity of concrete. These three parameters together supply valuable information about the corrosion extent of reinforcement in concrete. Some concrete samples were taken for determination of chloride content in order to verify the results from the nondestructive corrosion mapping. The results show that the measured corrosion rate is in good agreement with the chloride content measurement and the visual observations, while the half-cell potential in many cases is uncertain. Even though the resistivity of concrete alone cannot tell much information about reinforcement corrosion, it indeed helps the judgment of corrosion when together with the measurement of corrosion rate.