IMITATING NIAGARA FALLS

This article shows how waterjet technology for restoring concrete has begun to be used in the UK as a simple alternative to cumbersome hand-operated machinery. Conjet equipment, the first remote-controlled unit using jetstream technology, is being used to clean and repair damaged concrete safety parapets on a bridge on a stretch of the M4 at Port Talbot, South Wales. It is replacing a team of 25 hydraulic breakers for the same job; only one operator is needed to use the machine. Although a jackhammer team has traditionally been the best approach, it risks damaging good concrete and rebars besides breaking up bad concrete, and it has several other problems. It is claimed the Conjet solves all these problems and its principle is remarkably simple. A stream of water, travelling at twice the speed of sound, is released through a nozzle operating along a feed into the concrete. The water loosens the poor quality aggregate, but leaves the stronger aggregate intact. A computer with eight different programs enables the machine to be set up for particular measurements and specifications. This selectivity enables only damaged concrete to be removed, leaving a strong rough surface for bonding; rebars are also cleaned and left intact. (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00107859
• Corporate Authors:

  Reed Business Information, Limited

  Quadrant House, The Quadrant
  Brighton Road
  Sutton, Surrey  United Kingdom  SM2 5AS
• Authors:
  • Gethin, S
• Publication Date: 1990-10-11

Media Info

• Pagination: p. 27
• Serial:
  • CONTRACT JOURNAL
  • Publisher: Reed Business Information, Limited
  • ISSN: 0010-7859

Subject/Index Terms

• TRT Terms: Bridges; Cleaning; Concrete; Jet propelled aircraft; Reinforcing bars; Remote control; Repairing
• Uncontrolled Terms: Jets; Rebars; Repairs
• ITRD Terms: 3643: Hydraulic jetting; 3847: Maintenance; 4794: Reinforced concrete; 3635: Repair
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation; Materials;

Filing Info

• Accession Number: 00620071
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Mar 31 1992 12:00AM