Experimental investigations of within-test variability of non-destructive methods to determine concrete strength are reported. Rebound, indentation, ultrasonic (with direct and surface transmissions) and shearing rib methods were among those studied. Tests using each of these procedures were run on precast products such as piles or columns, and 200 mm cubes. Ordinary Portland cement crushed granite of maximum size 20 mm and river quartz sand were used to make the concrete. The mix was placed in steel moulds and compacted on either a vibrating table (for specimens), or a platform (for products). Both products and specimens were subjected to heat treatment. Within-test coefficients of variation Vi were calculated from each individual non-destructive readings at a location. Average within-test coefficients of variation were calculated for various intervals of concrete strength. Confidence limits were determined for both the upper and the lower confidence limits. The results indicate that the coefficient of variation of rebound number decreases with increasing concrete strength. With an increase in concrete hardness the spread of test results for rebound number decreases. The coefficient of variation does not depend upon concrete strength for the indentation and ultrasonic methods. The coefficient of variation and its spread in surface transmission are somewhat lower than indirect transmission. The greatest spread of test results is found for shear rib loading, but this may be due to frequent slippage of the shearing tool. (TRRL) (Author/TRRL)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • Leshchinsky, A M
    • Leshchinksy, M Y
    • Goncharova, A S
  • Publication Date: 1990-12


  • English

Media Info

  • Features: References;
  • Pagination: p. 245-8
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00623766
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Jul 31 1992 12:00AM