PHOTO-ELASTIC ANALYSIS OF SHRINKAGE MICROCRACKING IN CONCRETE

THE STRESS DISTRIBUTION IN CONCRETE DURING THE VARIATIONS IN VOLUME DUE TO HYDRATION OF THE CEMENT PASTE AT EARLY AGES IS REPORTED. A TWO-DIMENSIONAL MODEL WAS DEVISED FOR THE PHOTO-ELASTIC STUDY OF THE STRESS DISTRIBUTION. THE MODEL CONSISTED OF A SQUARE ARRAY OF CIRCULAR INCLUSIONS MADE OF PURE EPOXY POLYMER EMBEDDED IN A MATRIX MADE OF PLASTICIZED EPOXY RESIN. SHRINKAGE STRESSES DEVELOPED DURING THE CURING OF THE MATRIX AROUND THE ALREADY HARDENED INCLUSIONS. THE ELASTIC MODULI OF INCLUSIONS AND MATRIX WERE CHOSEN SO THAT THEIR RATIO APPROXIMATED TO THE RATIO OF THE ELASTIC MODULI OF AGGREGATE AND THE HARDENED CEMENT PASTE IN CONCRETE. ALTHOUGH THIS MODEL IS A SIMPLIFIED, PLANE CONFIGURATION OF THE THREE-DIMENSIONAL RANDOM ARRANGEMENT OF THE AGGREGATE IN CONCRETE, IT DEPICTS FAIRLY ACCURATELY THE STATE OF STRESS AROUND AGGREGATE PARTICLES. TENSILE STRESSES, DEVELOPING AT THE INTERFACE BETWEEN AGGREGATE AND CEMENT PASTE, CAUSE THE DEVELOPMENT OF MICROCRACKS AT THE INTERFACE DURING THE CURING PERIOD OF CONCRETE AND BEFORE ANY APPLICATION OF LOAD. THE EFFECT OF THE RATIO OF THE AVERAGE DIAMETER OF AGGREGATES TO THE AVERAGE CLEAR DISTANCE BETWEEN THEM UPON THE STRESS DISTRIBUTION WAS ALSO STUDIED. /A/RRL/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00249831
• Supplemental Notes:
  • Vol 21, No 66, PP 15-22, 8 FIG, 10 PHOT, 12 REF
• Authors:
  • Theocaris, P A
  • Koufopoulos, T
• Publication Date: 1969-3

Media Info

• Serial:
  • MAGAZINE OF CONCRETE RESEARCH
  • Publisher: Thomas Telford Limited
  • ISSN: 0024-9831

Subject/Index Terms

• TRT Terms: Aggregates; Cement; Concrete; Concrete curing; Cracking; Deformation curve; Epoxy resins; Hydration; Mathematical models; Matrices (Mathematics); Pastes; Photoelasticity; Polymers; Shrinkage
• Uncontrolled Terms: Concrete cracking; Models; Two dimensional
• Old TRIS Terms: Photoelastic studies; Shrinkage cracks
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00212990
• Record Type: Publication
• Source Agency: Road Research Laboratory /UK
• Files: TRIS
• Created Date: Apr 25 1971 12:00AM