THERMAL AND SHRINKAGE CRACKING IN REINFORCED CONCRETE SLABS

Following recent research, several mechanisms have been proposed for flexural cracking in reinforced concrete. Cracking also results from restrained volume changes in concrete, and the severity and consequences of such cracking should be considered in serviceability provisions of design codes. This paper reviews the mechanisms proposed by others for crack formation (bond slip, no slip) and suggests a 'tapered bond slip' crack to reconcile their differences. A new more general formula for crack width prediction is proposed, and the amount of reinforcement required for crack control is compared with the requirements of design codes. An experimental program was conducted to test the validity of the tapered bond slip crack mechanism, and good agreement with the crack width prediction equation was achieved. It is concluded that provided a minimum ratio of reinforcement is included in a reinforced concrete member, thermal and shrinkage crack widths are a function of reinforcement ratio, age and strength of concrete, and development length of reinforcement. Cover to reinforcement has relatively little influence on such cracks. This is in contrast to recommendations for flexural crack control given in the current SAA concrete structures code. (a) /TRRL/

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  • Corporate Authors:

    Institution of Engineers

    Science House, Gloucester and Essex Streets
    Sydney,   Australia 
  • Authors:
    • Brickell, A
    • Hoadley, P J
  • Publication Date: 1976

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Filing Info

  • Accession Number: 00149094
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Jul 2 1977 12:00AM