CORROSION OF REINFORCEMENT

The author reviews the causes and mechanisms of the chemical corrosion of concrete reinforcement suggesting precautions that could be taken to minimise it. Normally steel is protected by the layer of concrete which prevents oxidation and electrochemical corrosion. The protection of steel is reduced or made ineffective when the alkaline environment is destroyed by leaching with waste or partial neutralisation by chemical reaction between hydration products and CO2 from the atmosphere. Adequate cover is also required to resist 'spalling' caused by the increased volume of the corrosion products. Permeability is the most important factor; in impermeable concrete, the electrical conductivity is lower, capillary pores are few and small. Early corrosion fills the pores in a large volume round the corrosion site slowing down the diffusion of reactants, nearly stopping corrosion. The start of local corrosion is shown to be influenced by differences in potential in the steel surface. Chloride ions present in the cement paste surrounding the reinforcement tend to destroy the protective film on the steel, even in uncarbonated concrete. The presence of chlorides, however, only causes corrosion when water and oxygen are available. (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00105317
• Corporate Authors:

  Plenum Publishing Corporation

  233 Spring Street
  New York, NY  United States  10013
• Authors:
  • Neville, A
• Publication Date: 1983-6

Media Info

• Features: Figures; Photos; References;
• Pagination: p. 48-49
• Serial:
  • CONCRETE
  • Volume: 17
  • Issue Number: 6
  • Publisher: THE CONCRETE SOCIETY
  • ISSN: 0010-5317

Subject/Index Terms

• TRT Terms: Alkali; Carbon dioxide; Cement paste; Chemistry; Chlorides; Concrete; Corrosion; Electricity; Hydration; Ions; Leaching; Material reinforcement; Oxygen; Permeability; Prevention; Reinforced concrete; Reinforcing materials; Reinforcing steel; Spalling; Steel; Thickness; Water
• Uncontrolled Terms: Conductivity
• Old TRIS Terms: Alkalies
• ITRD Terms: 7165: Chemistry; 4755: Concrete; 5252: Corrosion; 6954: Electricity; 7314: Halide; 7195: Hydration; 7108: Oxygen; 5921: Permeability; 9149: Prevention; 4794: Reinforced concrete; 3471: Reinforcement (in mater); 5231: Spalling; 4542: Steel; 5933: Thickness; 4355: Water
• Subject Areas: Geotechnology; Highways; Materials; Planning and Forecasting; Security and Emergencies; I32: Concrete; I34: Steels and Metals; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00380439
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Jan 30 1984 12:00AM