THE INFLUENCE OF AGGREGATE PARTICLES ON THE LOCAL STRAIN DISTRIBUTION AND FRACTURE MECHANISM OF CEMENT PASTE DURING DRYING SHRINKAGE AND LOADING TO FAILURE

PRELIMINARY RESULTS FROM A COMPREHENSIVE INVESTIGATION INTO THE INFLUENCE OF THE STRUCTURE OF CONCRETE ON ITS INTERNAL AND OVERALL DEFORMATIONAL BEHAVIOR UNDER COMBINED STRESSES ARE INTRODUCED. TWO-DIMENSIONAL PLATE MODELS WERE LOADED IN UNIAXIAL COMPRESSION, AND THE LOCAL STRAIN DISTRIBUTION IN THE FINE MORTAR MATRIX AROUND AGGREGATE PARTICLES WAS MEASURED USING ELECTRICAL RESISTANCE STRAIN GAUGES AND PHOTO-ELASTIC COATINGS. TRIAXIAL STRAIN MEASUREMENTS AT DISCONTINUITY AND ULTIMATE STRESS WERE MADE ON CYLINDRICAL SPECIMENS OF THE FINE MORTAR MATRIX USING A SPECIAL HYDRAULIC TRIAXIAL CELL. THE LOCAL AND COMPOSITE MATERIAL STRAINS AT FRACTURE INITIATION IN THE PLATE MODELS WERE COMPARED WITH THE CORRESPONDING VALUES OBTAINED FROM THE TRIAXIAL COMPRESSION TESTS ON THE FINE CORRESPONDING VALUES OBTAINED FROM THE TRIAXIAL COMPRESSION TESTS ON THE FINE MORTAR MATRIX AND UNIAXIAL COMPRESSION TESTS ON IDEALIZED "THREE DIMENSIONAL" CONCRETES. RESULTS INDICATE THAT THE PRESENCE OF AGGREGATE PARTICLES CONSIDERABLY ALTER THE LOCAL STRAINS IN THE MORTAR MATRIX. THE RESTRAINING INFLUENCE OF STRONG, HARD AGGREGATES INDUCES SHRINKAGE CRACKS IN UNLOADED SPECIMENS WHICH MAY OR MAY NOT WEAKEN THE MATERIAL DEPENDING ON THE LOCAL AND APPLIED STRESS STATES. FOR THE MODELS TESTED UNDER UNIAXIAL COMPRESSION, CRACKING WAS INITIATED IN THE MORTAR MATRIX AT COMPOSITE MATERIAL STRAINS WHICH WERE SMALLER THAN FOR THE PURE MORTAR AND DECREASED WITH INCREASING VOLUME FRACTION OF COARSE AGGREGATE. /LCPC(A)/RRL/

• Supplemental Notes:
  • Vol 2, No 7, PP 73-84, 9 FIG, 10 PHOT, 23 REF
• Authors:
  • MCCREATH, D R
  • Newman, J B
  • Newman, K
• Publication Date: 1969-1

Media Info

• Serial:
  • Matls & Structures, Res & Testing /Fr/

Subject/Index Terms

• TRT Terms: Aggregates; Behavior; Cement; Compression tests; Deformation; Drying; Fracture mechanics; Impacts; Loads; Mathematical models; Matrices (Mathematics); Mortar; Particles; Pastes; Shrinkage; Strain (Mechanics); Strain measurement; Stresses; Structural members; Structural plates
• Uncontrolled Terms: Loading; Models; Plates; Two dimensional
• Old TRIS Terms: Compressive strength tests; Strains; Structural forms
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00212931
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: May 16 1971 12:00AM