It is the purpose of this project to investigate the variability of strength within and between structural elements of concrete of nominally the same strength mixed and placed on site. Considerations of the limit state theory of reinforced concrete design dictated an approach which resulted in derivations of values for the materials factor of safety for a number of concrete members. The non-destructive testing techniques of ultrasonic pulse velocity and rebound hammer were used on a total of 47 elements, comprising two different strength levels, being cast on a construction site. The results indicate that the variation in strength both within and between concrete members reduces with age. The evidence suggests that this variation is greater for mixes of lower strength. The experimentally derived values of the factor of safety, however, are independent of the strength level. Empirical values are presented of an early age 'quality acceptance factor' which is based on the pulse velocity technique.

  • Corporate Authors:

    Cement and Concrete Association

    52 Grosvenor Gardens
    London SW1W 0AQ,   England 
  • Authors:
    • Davis, S G
    • MARTIN, S J
  • Publication Date: 1973-11

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 24 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00261513
  • Record Type: Publication
  • Report/Paper Numbers: Tech. Rpt. 42.487
  • Files: TRIS
  • Created Date: Nov 12 1974 12:00AM