STATIC AND FATIGUE FRACTURES OF PORTLAND CEMENT MORTAR IN FLEXURE

EXPERIMENTAL WORK TO STUDY THE MECHANICS OF FATIGUE CRACKS PROPAGATION IN MORTAR IS PRESENTED. UNNOTCHED BEAMS WERE FATIGUE LOADED WITH TWO RANGES OF STRESS. NOTCHED BEAMS WERE SIMILARLY LOADED WITH THREE RANGES OF STRESS. THE EFFECT OF RANGE OF STRESS ON THE S-N CURVES WAS THUS PARTIALLY STUDIED. STRESS-STRAIN CHARACTERISTICS DURING FATIGUE LIFE WERE DETERMINED. MEASURED STRAINS WERE INTERPRETED IN TERMS OF CRACK LENGTH, THE CORRELATION BETWEEN COMPLIANCE AND CRACK LENGTH HAVING BEEN PRE-DETERMINED IN STATIC TESTS. THE PRODUCT OF THE CRITICAL CRACK LENGTH AND THE SQUARE OF THE MAXIMUM STRESS PROVED TO BE A CONSTANT NUMBER FOR EITHER UNNOTCHED BEAMS OR BEAMS WITH APPROXIMATELY EQUAL NOTCH DEPTHS. HOWEVER, THE MATERIAL CONSTANT WAS FOUND TO BE THE CRITICAL STRAIN-ENERGY RELEASE RATE, AS IT HAD ALMOST THE SAME NUMERICAL VALUE FOR BOTH NOTCHED AND UNNOTCHED BEAMS. COMPARING THESE VALUES FOR FATIGUES AND STATIC LOADINGS, IN THE CASE OF UNNOTCHED BEAMS, THE FORMER WAS FOUND TO BE 7.5 PER CENT LOWER. THE DIFFERENCE WAS ATTRIBUTED TO THE ELASTIC CREEP CAUSED BY THE MEAN STATIC LOAD. IN SPITE OF THIS DIFFERENCE IT COULD PERHAPS BE CONCLUDED THAT THE MATERIAL HAD THE SAME CRITERION OF FRACTURE IN BOTH FATIGUE AND STATIC LOADINGS, NAMELY THE STRAIN-ENERGY RELEASE RATE. /AUTHOR/

  • Supplemental Notes:
    • Series No 90, VOL 2, PP 1343-1382, 25 FIG, 4 TAB, 14 REF
  • Corporate Authors:

    University of Illinois, Urbana-Champaign

    Urbana, IL  United States  61801
  • Authors:
    • Glucklich, J
  • Publication Date: 1965

Subject/Index Terms

Filing Info

  • Accession Number: 00213448
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 9 1970 12:00AM