Expected service life for concrete bridges: Exposed to chlorides, a field study
Paper in proceedings, 1998
Even though the new observations are accurate the available data are few and the findings should be treated as indications. The five years of further exposure of the bridges gave no significant increase in the chloride ingress. In this investigation the position of the sampling point is more important than the increase in exposure time of the bridge. The distance from the road seems to be an important factor, both horizontally and vertically. Orientation of surfaces towards traffic splash and driving rain is also indicated to be an important factor. Chloride penetration clearly is a function of exposure conditions, both chloride(intensity) and climate(wetness). The parts of the bridges that were examined in this study, and the previous ones, are obviously fairly dry, properly because they are not significantly exposed to driving rain nor direct splash from the traffic. The chloride exposure for the columns beneath a bridge seems to be mainly airbome chloride following the air stream in the direction of the traffic. Other parts of bridges more exposed to direct splash of salt water could be very much better and provide better conditions for deeper chloride penetration.