The ranges of values over which chromium oxide has been reported to influence the properties of portland cement and its component minerals extend from 0.005 to greater than 2.0 weight percent. Of current interest is the reported increase in early strength development induced by its inclusion at the higher levels. In the present investigation literature on this topic was reviewed in an attempt to resolve the conflicting current results. Further, it was attempted to assess the industrial importance of chromium oxide by means of laboratory experiments to ascertain its relevance for cement production. With this aim, clinkers were prepared in the laboratory using typical raw materials, and cements made from them were examined principally for their strength development properties. The present findings indicate the addition chromium oxide to high lime saturation cement raw mixes can, in some cases, bring about an increase in strength. The magnitude of the improvement, when it occurs, is such that the 8 and 24 h strengths are numerically increased by similar amounts. In relative terms the improvement is thus better at 8 h (up to 60 percent), dropping to 15 percent at 1 day. Independent of whether an increase is obtained or not, a deterioration of late strength (28 days) of up to 15 percent was always observed. As a consequence of the main observed strength improvement occurring at 8 h, the addition of chromium oxide to cement raw mixtures should be considered as an alternative to other very early strength cements. The lack of reproducibility of obtaining the increased strengths and of a simple quality control technique for assessing whether activated clinkers are being manufactured or not, however, detracts from chromium oxide additions on an industrial scale. Finally, from a user's viewpoint, the problems associated with chrome eczema, although not unsolvable, would mean that chromium-containing cements and concretes would require more careful handling than normal.

  • Corporate Authors:

    American Ceramic Society

    65 Ceramic Way
    Columbus, OH  United States  43714
  • Authors:
    • Imlach, J A
  • Publication Date: 1975-5

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 519-522
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00097193
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM