Feature
Assessment and repair of bridges subjected to de-icing salts
Authors
Ulrik Sloth Andersen Project Director, MSc (Ramboll), (Denmark).
Henrik Nielsen Project Manager, MSc, Danish Road Directorate, and member of the World Road Association Technical Committee 4.3 on Road Bridges
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.