CRUSHED STONE: PRODUCTION AND GRADATION

IT IS PREDICTED THAT A MILLION TONS PER DAY OF CRUSHED LIMESTONE AND DOLOMITE FOR ROADSTONE AND CONCRETE WILL BE REQUIRED TO SATISFY THE PROJECTED DEMAND FOR EACH OF THE NEXT SEVERAL YEARS. THE EQUIPMENT REQUIRED TO HANDLE THIS TERRIFIC AMOUNT OF CRUSHED MATERIAL IS DISCUSSED. THE INVESTMENTS IN PRODUCTION EQUIPMENT AND PLANT SITES NECESSARY TO MEET THE CURRENT DEMAND FOR CRUSHED STONE CAN BE ESTIMATED TO BE IN THE BILLIONS OF DOLLARS. IT IS POSSIBLE BY VARYING THE SIEVE SIZES AND THE AMOUNTS OF MATERIALS PASSING A GIVEN SIEVE TO OBTAIN EITHER AN AGGREGATE CONTAINING ESSENTIALLY A SINGLE SIZE OR ONE HAVING A BALANCED COMBINATION OF DECREASING SIZES WHICH IS COMMONLY TERMED DENSE GRADED, THE MOST COMMON TYPE OF CRUSHED STONE PRODUCED FOR CONCRETE OR HIGHWAY WORK. THE SIMPLIFIED PRACTICE RECOMMENDATION (SPR) WAS INITIATED IN 1948 BY THE BUREAU OF PUBLIC ROADS: (1) TO DEVELOP A MINIMUM NUMBER OF STANDARD AGGREGATE GRADATIONS THAT CAN BE UNIFORMLY ADOPTED NATIONWIDE FOR GENERAL USAGE, WHILE AT THE SAME TIME, RECOGNIZING THE NEED FOR SOME VARIATION BY SPECIAL PROVISIONS TO FIT LOCALLY AVAILABLE MATERIALS, (2) TO ACHIEVE UNIFORMITY IN THE NUMBER AND SIZES OF SIEVES TO BE USED IN SPECIFYING THE AGGREGATE GRADATIONS, AND (3) TO DEVELOP AND ADOPT A SIMPLE AND UNIFORM SYSTEM FOR IDENTIFICATION OF THE STANDARD AGGREGATE GRADATIONS. WITH THE ADDITION OF SAND SIZES AND MINERAL FILLERS, THE SPR COULD ADEQUATELY DESCRIBE THE MAJORITY OF CRUSHED AGGREGATES USED IN CONCRETE AND HIGHWAY CONSTRUCTION. PLOTS ARE PRESENTED OF GRADATION CURVES FOR DENSE GRADED BASE AGGREGATES FOR SEVERAL STATES. A UNIFORM METHOD OF DESCRIBING AGGREGATES HAS NOT BEEN ADOPTED AND THIS IS THE STUMBLING BLOCK IN THE PATH TO UNIFORMITY FOR AGGREGATE GRADATIONS.

• Supplemental Notes:
  • Vol 4, No 13, PP 14-15, 35-39, 6 FIG, 5 TAB, 6 PHOT
• Corporate Authors:

  National Limestone Institute

  ,    
• Authors:
  • Copas, T L
• Publication Date: 1967

Subject/Index Terms

• TRT Terms: Aggregate gradation; Concrete; Concrete aggregates; Construction equipment; Crushed limestone; Crushed rock; Crushers; Dense graded aggregates; Dolomite; Road construction; Sieves; Specifications; Standardization
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00217576
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 22 1994 12:00AM