DIFFUSION AND PROTECTION MECHANISMS OF ORGANIC CORROSION INHIBITORS IN CONCRETE

In this paper the properties of three amine based inhibitors, dimethyl ethanolamine, dicyclohexylamine nitrite and a commercial MCI inhibitor are discussed. Electrochemical measurements in simulated concrete solutions have shown that all three of these inhibitors offer good protection in both admixture and remedial conditions (when the inhibitor is applied after corrosion of the steel specimen has already taken place). In addition, polarization measurements have confirmed the mixed behaviour of these inhibitors. The diffusion characteristics of all three inhibitors have been followed for several months using concrete membranes with 0.45 and 0.6 w/c ratio and variable thickness. It appears that dimethyl ethanolamine diffuses most rapidly, followed by the commercial MCI product. Using Fick's first law for modelling the data, diffusion coefficients between 10 to the power of minus 12 and 10 to the power of minus 13 square metres per second have been calculated. In addition, the application of these inhibitors to reinforced concrete specimens, as well as the synergy between cathodic protection/applied electric field and organic inhibitors, has been investigated. The level of protection and the time dependency of inhibitor behaviour appears to be different in the concrete specimens compared to the simulated concrete pore water solution experiments, highlighting the need for longer term testing in concrete. The electric field/inhibitor experiments explore the possibility of a strengthened passive film using the combined protection techniques and/or the electric field driven enhanced diffusion of the inhibitor to the steel surface, however it has been difficult to assess any short term synergy in this case at this stage. (a) For the covering entry of this conference, please see IRRD abstract no. E200447.

• Corporate Authors:

  AUSTRALASIAN CORROSION ASSOCIATION

  PO BOX 634
  BRENTFORD SQUARE, VICTORIA  Australia  3131
• Authors:
  • Forsyth, M
  • CHERRY, B W
  • PHANASGAONKAR, A
• Conference:
  • AUSTRALASIAN CORROSION ASSOCIATION CONFERENCE, 1999, SYDNEY, NEW SOUTH WALES, AUSTRALIA
• Publication Date: 1999-11

Language

• English

Media Info

• Features: References;
• Pagination: 6P (PAPER 39-082)

Subject/Index Terms

• TRT Terms: Concrete; Conferences; Corrosion; Diffusion (Optics); Electrodes; Inhibitors (Chemistry); Prevention
• ITRD Terms: 4755: Concrete; 8525: Conference; 5252: Corrosion; 6769: Diffusion; 6951: Electrode; 7137: Inhibitor; 9149: Prevention
• Subject Areas: Data and Information Technology; Security and Emergencies;

Filing Info

• Accession Number: 00794886
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, ATRI
• Created Date: Jul 7 2000 12:00AM