BOND BETWEEN AGGREGATES AND MORTAR AND ITS EFFECT ON THE STRENGTH OF CONCRETE /IN DANISH/

AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF BOND BETWEEN PORTLAND CEMENT MORTAR AND COARSE AGGREGATES ON THE COMPRESSIVE STRENGTH AND MODULUS OF ELASTICITY OF CONCRETE IS PRESENTED. THE INVESTIGATION WAS LIMITED TO THE CASE IN WHICH ULTIMATE RUPTURE DOES NOT IMPLY FRACTURING OF THE COARSE AGGREGATE PARTICLES, I.E. THE STRENGTH OF AGGREGATES WAS MUCH GREATER THAN THE STRENGTH OF THE MORTAR MATRIX. THE EFFECT OF BOND STRENGTH WAS EVALUATED BY COMPARING THE STRENGTH OF "NATURAL" BOND CONCRETE WITH THE STRENGTH OF CONCRETE IN WHICH THE COARSE AGGREGATES HAD BEEN COATED WITH A THIN LAYER OF SOFT PLASTIC (ABOUT 12 MICRONS IN THICKNESS). GLASS MARBLES WITH A DIAMETER OF ABOUT 16 MM. WERE USED AS THE EXPERIMENTAL TYPE OF COARSE AGGREGATES. WITH COATED AGGREGATES, THE BOND STRENGTH WAS ASSUMED TO BE ZERO. IN THE TESTS, THE CONCENTRATION (BY VOLUME) OF THE COARSE AGGREGATES AND THE STRENGTH OF THE MORTAR MATRIX WERE VARIED. THE LETTER VARIATION WAS OBTAINED BY VARYING THE AGE OF TESTING. THE RESULTS OF THE STRENGTH TESTS ARE PRESENTED IN TABLES. THEY DEMONSTRATE THAT THE COMPRESSIVE STRENGTH OF CONCRETE IS HIGHLY INFLUENCED BY THE BOND BETWEEN MORTAR AND COARSE AGGREGATES OF THE TYPE INVESTIGATED. THE EFFECT INCREASES WITH INCREASING AGGREGATE CONCENTRATION AND WITH INCREASING AGE. THUS, FOR INSTANCE, AT LATER AGES AND WITH A COARSE AGGREGATE CONCENTRATION OF 50 PERCENT, THE EXISTENCE OF BOND RAISED THE STRENGTH ABOUT 2.5 TIMES ABOVE THE STRENGTH OF CONCRETE WITHOUT BOND. THE RESULTS FURTHER INDICATE THAT MORTAR STRENGTH AND BOND STRENGTH ARE NOT PROPORTIONAL, THE LATTER INCREASING RELATIVELY FASTER THAN THE FORMER WITH INCREASING AGE. THE DATA OBTAINED OF THE PROPERTIES OF CONCRETE WITH ZERO BOND STRENGTH MAY BE USED TO CHARACTERIZE OTHER TYPES OF COARSE AGGREGATES AS REGARDS THEIR ABILITY TO CONTRIBUTE TO THE STRENGTH OF CONCRETE THROUGH THE ESTABLISHMENT OF BINDINGS TO THE MORTAR. /RRL/A/

  • Supplemental Notes:
    • 66 Pp, 12 FIG, 14 TAB, 4 PHOT, 18 REF
  • Corporate Authors:

    Betonforskningsaboratoriet /Den

    ,    
  • Authors:
    • Nepper-christensen, P
    • Nielsen, T P
  • Publication Date: 1968-2

Subject/Index Terms

Filing Info

  • Accession Number: 00212974
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Aug 3 1970 12:00AM