The time elapsed between the initial mixing and testing of concrete is important when the sample may have to be carried several miles from the site. The effect of age on the results of analysis, using the rapid analysis machine (ram) method, is investigated. The use of retarding admixtures is also examined. Results show that there is a consistent decrease in cement content with age. This decrease is generally less than 5 per cent up to two hours, but reductions exceeding 20 per cent can be expected after six hours. However, because this reduction with time is predictable, and is not significantly affected by mix proportions or cement type, a chart is given which can be used to estimate the effect of age. It was found that the addition of retarder dosages of up to six times normal eliminated any apparent reduction in cement content with age for up to six hours. In fact, accurate fresh concrete analysis could also be carried out after up to 48 hours, provided that 12 times the normal dose of retarder was used. (TRRL)

  • Availability:
  • Corporate Authors:

    Cement and Concrete Association

    Wexham Spring
    Slough SL3 6PL, Buckinghamshire,   England 
  • Authors:
    • SANGHA, C M
    • WALDEN, P J
  • Publication Date: 1980-8

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 27-28
  • Serial:
    • Volume: 14
    • Issue Number: 8
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00334083
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Sep 16 1981 12:00AM