FOSROC trials the roads in Austria

FOSROC trials the roads in Austria

Keywords: Corrosion, Bridge, Roads

FOSROC is using Ebonex technology to help civil engineers in Austria working on trials on a major road bridge refurbishment project

The Lieserschulucht road bridge carries the main motorway connecting Northern Europe to Italy, over a river in the mountainous Carinthia region of Austria.

The harsh winters in this area necessitate the use of de-icing salts, which over the years have leaked through surface construction joints onto the supporting cross beams. This in turn has led to the accumulation of high levels of aggressive chloride salts within the underlying concrete structure which have attacked the reinforced steel, causing some corrosion to occur.

After detailed analysis of the bridge, it was found that chloride contamination levels were above average whilst a further electrochemical analysis found clear evidence that corrosion throughout the structure had already begun. A visual inspection of the site confirmed these findings with surface concrete spalling evident in certain areas due to the deterioration of steel reinforcement.

The application of any solution to the corrosion was complicated further by the fact that the beams contained very heavy steel reinforcement and access to the back of each was blocked by an adjacent beam.

In trials, CIS of Vienna designed and installed Ebonex on two test beams which are part of a wider evaluation of cathodic protection systems currently being undertaken by the local Carinthian University.

Ebonex discrete anodes can be installed into the body of the reinforced concrete structure and provide distinctive advantages over other systems. This centres around the distribution of protective impressed currents in deeply buried steel and the fact that the currents generated can be high where steel is of a high density.

The anodes have been buried into predrilled holes on the beam face using the proprietary Ebofix grout, specifically deigned to enhance current distribution and eliminate short circuits. Each individual unit is connected and oxygen vented to the surface of the concrete.

In addition to the front face, the beam-ends were also treated by using large Ebonex anodes, an application, which mitigates the need for alternative surface mounted treatments keeping installation costs and access issues to a minimum.

It is expected from the data returned to date that the Ebonex discrete anode systems should provide protection for at least 20 years.