Assessment and repair of bridges subjected to de-icing salts

Illustrations © Ramboll Denmark A/S

Many highway bridges in Denmark were constructed during the period from 1960 to 1980. Most of the bridges were built from reinforced concrete, often using aggregates sensitive to alkali-silica reactions (ASR).

The average temperature is close to 0°C in December, January and February, thus leading to many days with frost and a heavy usage of de-icing salts, the use of which in Denmark (43,000 km2) is approximately 300,000 ton per year.

This paper presents cases where reinforced concrete (RC) and post-tensioned bridges have undergone major rehabilitation in order to halt the deterioration (corroded reinforcement and aggravated alkali-silica-reactions) primarily caused by de-icing salts.