ALKALI SLEUTHS ROOT OUT DEVON BRIDGES. INVESTIGATION OF ALKALI AGGREGATE REACTION DAMAGE TO CONCRETE STRUCTURES ON THE A38 IN DEVON

An account is given of a report by Mott Hay and Anderson (MHA) on investigations into three Devon bridges on the A38 trunk road near plymouth which are suffering from alkali aggregate reaction (AAR). This was found to be due to the use of concrete made with cement from Blue Circle Industries' Plymstock works and a dredged South Coast aggregate containing chert--known to be liable to AAR deterioration. The mechanism of damage is explained and basically involves the reaction between caustic alkalis and reactive silica to produce a gel which can absorb water and swell. Particular areas where trouble is occurring are identified, the worst damage being found to occur in pile caps in wet ground and areas where exposure to the weather is greatest. MHA's strategy for saving the structures is described as being mainly concerned with keeping them dry by improved deck waterproofing, watertight expansion joints and water repellant coatings but has also included traffic restrictions. (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03077683
• Corporate Authors:

  Institution of Civil Engineers

  One Great George Street, Westminster
  London,   United Kingdom  SW1P 3AA
• Authors:
  • Parkinson, J
• Publication Date: 1983-11

Media Info

• Features: Figures; Photos;
• Pagination: p. 18-19
• Serial:
  • NEW CIVIL ENGINEER
  • Issue Number: 565
  • Publisher: EMAP CONSTRUCT LIMITED
  • ISSN: 0307-7683

Subject/Index Terms

• TRT Terms: Aggregates; Alkali; Bridge decks; Bridges; Cherts; Expansion joints; Groundwater; Highway bridges; Loss and damage; Reactive aggregates; Seal coats; Silica gel; Traffic restraint; Water repellents; Waterproofing; Waterproofing materials; Weather
• Geographic Terms: United Kingdom
• Old TRIS Terms: Alkalies
• ITRD Terms: 4577: Aggregate; 7353: Alkali; 3455: Bridge; 1614: Damage; 4170: Flint; 4383: Ground water; 5939: Hydrophobic; 8119: United Kingdom; 3492: Waterproofing course (bridge); 2545: Weather
• Subject Areas: Bridges and other structures; Geotechnology; Highways; I36: Aggregates;

Filing Info

• Accession Number: 00384526
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: May 30 1984 12:00AM