THE VARIABILITY OF INDIRECT-TENSILE AND COMPRESSIVE STRENGTHS OF CONCRETE IN ROAD PAVEMENT CONTRACTS

In 1971 the Department of The Environment issued Technical Memorandum H10/71 which introduced the use of the indirect-tensile test on cylinders, in place of the traditional compressive test on cubes, for the specification of concrete strength in road pavements. The memorandum has since been incorporated into the 1976 edition of the specification for road and bridge works issued by the Department of Transport. With the object of assessing the effects of the new specification on the variability and level of strength results, cubes and cylinders, additional to those normally required for compliance with the specification, were made and tested on ten major road contracts. The overall standard deviation of the indirect-tensile and compressive strength results at 28 days was 0.33 and 4.6 n/mm 2 respectively. The mean strengths at 28 days on the various sites ranged from 29.7 to 46.0 n/mm 2 in compression and from 2.56 to 3.46 n/mm 2 in indirect tension with overall mean strengths of 39.8 and 3.04 n/mm 2 respectively. Testing variability at 28 days was higher for the indirect-tensile test than for the compression test in terms of coefficient of variation. The values obtained were 6.1 per cent and 3.9 per cent respectively. Although testing variability of the cylinders was better than that found in earlier site studies, further improvement is desirable to permit a more sensitive control of concrete quality. (a) (TRRL)

  • Availability:
  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • Franklin, R E
    • Gibbs, W E
    • BURTWELL, M H
  • Publication Date: 1979

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Filing Info

  • Accession Number: 00310570
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: TRRL SR 477 Monograph
  • Files: ITRD, TRIS, ATRI
  • Created Date: Jul 22 1980 12:00AM