THE PENETRATION OF CHLORIDES INTO HARDENED CEMENT PASTES

The penetration of chloride ions into hardened cement pastes (hcp) has been measured by chemical analysis, x ray diffraction and thermal analysis. The penetration of chloride depends on the permeability; thus the greater the w/c ratio the greater is the penetration. The concentration of chloride in the hcp is dependent on the concentration of the surrounding solution. The chloride ions react with the anhydrous tricalcium aluminate in the unhydrated cement left in the hcp but not with the complex hydrated calcium aluminate salts including ettringite. Calcium mono-chloroaluminate hydrate is formed, but not all the chloride which penetrates reacts to form this mineral. The quantity of chloroaluminate formed is independent of the chloride concentration in the hcp. From a study of the pore size distribution of the hcp by mercury intrusion porosimetry it is deduced that the penetrating chloride reduces the sizes of the small pores thus reducing the permeability. (TRRL)

• Availability:
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• Corporate Authors:

  Pergamon Press, Incorporated

  Maxwell House, Fairview Park
  Elmsford, NY  United States  10523
• Authors:
  • Midgley, H G
  • Illston, J M
• Publication Date: 1984-7

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 546-558
• Serial:
  • Cement and Concrete Research
  • Volume: 14
  • Issue Number: 4
  • Publisher: Elsevier
  • ISSN: 0008-8846
  • Serial URL: http://www.sciencedirect.com/science/journal/00088846

Subject/Index Terms

• TRT Terms: Cement paste; Chemical analysis; Chemical concentration; Chlorides; Diffraction; Measurement; Pendulum tests; Permeability; Pore size distribution; Porosimeters; Thermal analysis; Water cement ratio; X rays
• Uncontrolled Terms: X-ray diffraction
• ITRD Terms: 4767: Cement paste; 7163: Chemical analysis; 7132: Concentration (chem); 6779: Diffraction; 7314: Halide; 4714: Mix design; 6285: Penetration; 5921: Permeability; 7152: Thermal analysis; 6728: X ray
• Subject Areas: Highways; Materials; Planning and Forecasting; I32: Concrete; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00393310
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Jun 30 1985 12:00AM