THE CONTROL OF CRACKING OF CONCRETE

THE CRACKING OF CONCRETE IN HIGHWAY PAVEMENTS AND STRUCTURES IS UNDESIRABLE SINCE CRACKING OF THE CONCRETE IS ASSOCIATED WITH THE DETERIORATION OF BOTH THE CONCRETE AND REINFORCING STEEL. MANY STUDIES ON THE PHENOMENON OF CRACKING IN PLAIN AND REINFORCED CONCRETE HAVE BEEN CONDUCTED; HOWEVER, THESE INVESTIGATIONS HAVE CORRELATED THE CRACKING OF CONCRETE WITH VARIOUS PARAMETERS OF THE CONCRETE AND THE ENVIRONMENT, BUT HAVE NOT CONSIDERED THE MECHANISM OF CRACKING. THIS REPORT SUMMARIZES A THREE-PHASE INVESTIGATION THAT WAS UNDERTAKEN TO PROVIDE A BETTER UNDERSTANDING OF THE INITIATION AND GROWTH OF CRACKS IN CONCRETE. THIS UNDERSTANDING OF CRACK DEVELOPMENT IS ESSENTIAL IF CRACKING OF CONCRETE STRUCTURES IS TO BE CONTROLLED. THE EFFECT OF SEVERAL CONCRETE PARAMETERS ON THE FRACTURE TOUGHNESS (MATERIAL'S RESISTANCE TO PROPAGATION OF AN EXISTING FLAW) IS PRESENTED. A SYSTEMS-TYPE ANALYSIS IS PRESENTED TO DESCRIBE THE COMPLEX CRACKING MECHANISM IN CONCRETE STRUCTURES AND MODELS ARE DEVELOPED FOR STUDYING CRACKING IN CONCRETE BEAMS AND RIGID PAVEMENTS. AN APPROXIMATE SOLUTION FOR THE PROBLEM OF SHRINKAGE STRESSES IN PLAIN AND REINFORCED CONCRETE MEMBERS EXTERNALLY LOADED IS DEVELOPED. THE EFFECTIVE FRACTURE TOUGHNESS OF CONCRETE WAS FOUND TO BE DIRECTLY PROPORTIONAL TO BOTH COARSE AGGREGATE CONTENT AND GRADATION OF COARSE AGGREGATE. THUS, BY INCREASING OR DECREASING THE COARSE AGGREGATE CONTENT, OR INCREASING OR DECREASING THE MAXIMUM AGGREGATE SIZE, OR BY A COMBINATION OF BOTH, THE FRACTURE TOUGHNESS CAN BE ADJUSTED. HOWEVER, OTHER SERVICE REQUIREMENTS NEED TO BE CONSIDERED IN THE DESIGN OF CONCRETE MIXTURES, EVEN THOUGH IT MAY MEAN A SACRIFICE IN DESIRED FRACTURE TOUGHNESS. /AUTHOR/

  • Corporate Authors:

    University of Illinois, Urbana-Champaign

    Urbana, IL  USA  61801

    Illinois Department of Transportation

    Division of Highways, 2300 South Dirksen Parkway
    Springfield, IL  USA  62764

    Bureau of Public Roads /US

    400 7th Street, SW
    Washington, DC  USA  20590
  • Authors:
    • Naus, D J
    • Rejali, H M
    • Raecke, D
    • Lott, J L
    • Kesler, C E
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00212086
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Report/Paper Numbers: Ihr-92
  • Files: TRIS
  • Created Date: Sep 28 1970 12:00AM