CHLORIDE EXTRACTION ON THE MIDLAND LINK VIADUCTS

This paper describes a trial of the desalination process on an abutment capping beam on the Midlands Link Motorway Viaducts, carrying the M5 and M6 motorways through the West Midlands conurbation of England. Early failure of the Viaduct's expansion joints led to leakage through the bridge decks of water heavily contaminated by chlorides from road deicing salts. Various repair options have been established. Although desalination could be cost-efective, a trial was conducted, to investigate and if possible quantify possible secondary desalination effects. Firstly, it was necessary to find how much chloride needed removing, and assess how reinforcement corrosion could be limited in the long term. Then an investigation was needed of whether desalination would promote the alkali-silica reaction (ASR), whose risk arises because desalination raises alkalinity levels at the reinforcement surfaces. The paper describes the laboratory work on nine cores of the structure, and the pre-treatment, treatment, and post-treatment phases of the site trial. The trial results showed the success of the desalination process. Before the trial, the chloride level in the capping beam exceeded 0.4% by weight of cement over most of the surface and 1% in some parts; it is now generally below 0.4%. No ASR increase was detected.

  • Availability:
  • Corporate Authors:

    PALLADIAN PUBLICATIONS LTD

    THE OLD FORGE
    ELSTEAD, SURREY  United Kingdom  GU8 6DD
  • Authors:
    • PATE, S J
  • Publication Date: 1996

Language

  • English

Media Info

  • Pagination: p. 16-9
  • Serial:
    • CONSTRUCTION REPAIR
    • Volume: 10
    • Issue Number: 4
    • Publisher: PALLADIAN PUBLICATIONS LTD
    • ISSN: 0967-0726

Subject/Index Terms

Filing Info

  • Accession Number: 00729740
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Dec 26 1996 12:00AM