This report presents the results from a research project financed by Trafikverket, the Swedish Transport Administration, co-financed by Cementa AB.

In this part of the project work about 35 chloride profiles and ten moisture profiles have been measured from various types of concrete specimens exposed to a de-icing salt highway environment for about 20 years. The non-destructive technique, RapiCor, for corrosion measurement was used to assess the conditions of steel embedded in concrete beams with different types of binder and water-binder ratios. The ClinConc model were used to predict chloride ingress in concrete. Some laboratory test methods and numerical simulations were carried out to study the behaviour of concrete after long-term exposure.

The results show that chloride ingress profiles measured after 20 years’ exposure under the de-icing salt highway environment are in general lower than those measured after the similar exposure duration under the marine splash environment.

Non-destructive corrosion measurement by RapiCor instrument is in general in reasonably good agreement with chloride ingress. The corrosion rust observed from the destructive examination verified again that the non-destructive technique RapiCor is a useful tool for detection of ongoing corrosion of steel in concrete.

The ClinConc model in general gives reasonably good prediction of chloride ingress front in the bulk concrete but not in the near surface zone due to the drying-wetting cycles in the highway environment. After a certain modification with the consideration of redistribution of bound chloride in the near surface zone, the model can reasonably well describe the chloride ingress profiles measured from the exposure site.