EFFECT OF AGGREGATE TYPE ON THE PROPERTIES OF SHRINKAGE - COMPENSATING CONCRETE

EXPANSIVE CEMENT CONCRETES, IF ADEQUATELY RESTRAINED BY REINFORCING STEEL, CAN MINIMIZE OR PREVENT THE DEVELOPMENT OF CRACKS DUE TO DRYING SHRINKAGE. SUCH CONCRETES ARE REFERRED TO AS SHRINKAGE-COMPENSATING. REPORTED ARE RESULTS OF AN INVESTIGATION UNDERTAKEN TO DETERMINE THE EFFECT OF AGGREGATE TYPE ON THE PROPERTIES OF SHRINKAGE-COMPENSATING CONCRETES. INCLUDED IN THIS STUDY WERE 3 TYPES OF NATURAL AGGREGATES AND ONE LIGHTWEIGHT AGGREGATE. TWO TYPES OF CEMENT WERE USED. ONE WAS THE SHRINKAGE-COMPENSATING CEMENT THAT WAS A BLEND OF 15 PERCENT BY WEIGHT OF CALCIUM SULFOALUMINATE EXPANSIVE COMPONENT AND 85 PERCENT OF TYPE V PORTLAND CEMENT. THE SECOND CEMENT USED IN THE CONTROL CONCRETES WAS 100 PERCENT TYPE V PORTLAND CEMENT. THE EXPANSION AND SHRINKAGE CHARACTERISTICS OF THE SHRINKAGE-COMPENSATING CONCRETES WERE DETERMINED FOR BOTH RESTRAINED AND UNRESTRAINED PROSMS. COMPRESSIVE STRENGTH AND MODULUS OF ELASTICITY WERE DETERMINED FOR UNRESTRAINED CYLINDRICAL SPECIMENS. ALL CONCRETES HAD A CEMENT CONTENT OF 5.5 SCY AND A WATER-CEMENT RATIO OF 0.58 BY WEIGHT. WITH THESE FIXED MIX PROPORTIONS, THE SLUMP OF THE CONCRETES WITH THE 4 DIFFERENT TYPES OF AGGREGATE VARIED FROM 2 TO 4 IN. FROM THE RESULTS OF THIS INVESTIGATION IT IS CONCLUDED THAT THE AGGREGATE TYPE IS AN IMPORTANT FACTOR IN THE PROPERTIES OF A SKRINKAGE-COMPENSATING CONCRETE. SHRINKAGE-COMPENASTING CONCRETE MIXES MUST BE SO DESIGNED THAT THEIR RESTRAINED EXPANSION IS OF SUFFICIENT MAGNITUDE TO COMPENSATE FOR THE POTENTIAL SHRINKAGE OF THE CONCRETE CONTAINING A CERTAIN TYPE OF AGGREGATE. THE EXPANSION AND SHRINKAGE BEHAVIOR OF A SHRINKAGE-COMPENSATING CONCRETE IS RELATED TO ITS MODULUS OF ELASTICITY. CONCRETES OH HIGH ELASTIC MODULUS EXHIBIT A LARGER EXPANSION THAN DO CONCRETES OF LOWER MODULUS OF ELASTICITY. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 82-90
  • Monograph Title: Construction and construction equipment
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00215351
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Nov 9 1970 12:00AM