POST-TENSIONED PRESTRESSING CABLES IN DUCTS

This article reviews the development of new specifications for grouting post-tensioning cable ducts in the UK. In September 1992, the Department of Transport introduced a moratorium on the use of grouted duct tendons in bridges. Soon afterwards, a joint Working Party of the Concrete Society and the Concrete Bridge Development Group was set up to examine all aspects of post-tensioning. It published interim guidelines in July 1993, which found leakage of water to be the major problem. Partially grouted tendons usually do not corrode, if they are not subjected to moisture and a replenishment of oxygen. The main risks of corrosion of tendons arise from: (1) incompletely grouted ducts; (2) leakage from expansion joints; (3) leakage through deck waterproofing; and (4) penetration of concrete through construction joints. Four primary measures were suggested: (1) a duct that is also a protective barrier, with sealed joints; (2) reduction of the maximum water/cement ratio; (3) full-scale trials of grouting; and (4) treating grout as a specialist operation. In 1994, the Transport Research Laboratory (TRL), on behalf of the DoT, commissioned Gifford and Partners to monitor grouting operations in the field and report on trials.

  • Availability:
  • Corporate Authors:

    THE CONCRETE SOCIETY

    112 WINDSOR ROAD
    SLOUGH, BERKSHIRE  United Kingdom  SL1 2JA
  • Authors:
    • Clark, G
  • Publication Date: 1995

Language

  • English

Media Info

  • Pagination: p. 27-8
  • Serial:
    • CONCRETE
    • Volume: 29
    • Issue Number: 4
    • Publisher: THE CONCRETE SOCIETY
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00715997
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Jan 31 1996 12:00AM