OPTIMUM SIZE COARSE AGGREGATE FOR PORTLAND CEMENT CONCRETE PAVING

BASIC CONSIDERATIONS WHICH WOULD DETERMINE THE OPTIMUM SIZE ARE REVIEWED. IN DISCUSSION OF THE PRINCIPLES OF STRENGTH DEVELOPMENT, DATA ARE PRESENTED WHICH CONTRADICTS THE ESTABLISHED CONCEPT OF THE RELATIONSHIP BETWEEN WATER-CEMENT RATIO AND STRENGTH. NOTABLE RESEARCH ON THE SUBJECT IS QUOTED. DATA INDICATE THAT HIGHEST STRENGTHS ARE OBTAINED WITH AGGREGATE IN 0.75 INCH TO 1.5 INCH RANGE IN SPITE OF NORMAL REDUCTIONS IN MIXING WATER FOR THE LARGER SIZE AGGREGATE. THE EFFECT OF SIZE OF COARSE AGGREGATE ON STRENGTH AND MIXING WATER REQUIREMENTS IS GRAPHICALLY ILLUSTRATED, AS IS ALSO, THE RELATIONSHIP BETWEEN WATER-CEMENT RATIO AND STRENGTH OF CONCRETE. THE RELATIONSHIPS OF WATER REQUIREMENTS AND STRENGTH TO FINENESS MODULUS OF TOTAL AGGREGATE WAS INVESTIGATED. THIS REVEALED THAT AGGREGATES IN THE MAXIMUM SIZES RECOMMENDED PRODUCE THE HIGHEST STRENGTH. FIELD STRENGTH TEST RESULTS ON THE ACCEPTABILITY OF CONCRETE QUALITY ON PAVING PROJECTS ARE REVIEWED. FIELD RESEARCH BY HIGHWAY DEPARTMENTS HAS BEEN CONDUCTED TO DETERMINE THE EFFECT OF A REDUCTION IN MAXIMUM SIZE AGGREGATES. BASED ON THESE EXPERIMENTS PROJECTS, THE SPECIFICATIONS WERE REVISED TO PERMIT THE OPTION OF USING A SINGLE SIZE OF COARSE AGGREGATE IN TWO SEPARATE SIZES. THE SINGLE SIZE COARSE AGGREGATE IS AASHO OR ASTM SIZE NO. 57. EXPERIENCE IN OHIO REVEALS THAT ALONG WITH WORKABILITY, THE UNIFORMITY OF CONCRETE MIXTURE IS IMPROVED WHEN MAXIMUM SIZE AGGREGATE IS REDUCED. HANDLING CONSIDERATIONS, AVAILABILITY, AND ECONOMY ARE OTHER ASPECTS REVIEWED.

  • Supplemental Notes:
    • TECH BLTN NO 15
  • Corporate Authors:

    American Concrete Paving Association

    1211 West 22nd Street
    Oak Brook, IL  United States  60523
  • Publication Date: 1972-11

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 21 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00214268
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 20 1974 12:00AM