A quality control program is described which has proved successful in furnishing graded aggregate materials to job sites some distance from the processing plant. The program involves testing at a central research Laboratory (sulfate soundness loss, abrasion loss, specific gravity and absorption, deleterious materials identification, moisture-density determinations, and others) and 6 district laboratories (sieve analyses and loss by washing, unit weight, and moisture content). District laboratory technicians play a vital role in an efficient program, and they must be throughly skilled in sampling and testing as well as being highly effective in communicating with the plant manager, sales representatives, customers and their representatives. The methods of reporting data are detailed. Two processes for maintaining a control on the variation in grading are: blending plants in which two or more standard sizes of aggregate, and in some cases a mineral filler, are accurately proportioned to produce a dense-graded aggregate well within the specified job control limits; and semi-automated aggregate processing plants which crush and screen the raw material into separate size fractions and blend them by regulated feeders into the desired product. Rapid feedback of test results to plant supervisory personnel is the key to a successful quality control program during production. An example is cited where close tolerances on five control sieve sizes were successfully met for a job involving rail shipment and job site stockpiling of the final product, and achievement requiring the complete cooperation of the producer and the contractor.

  • Supplemental Notes:
    • Proceedings from a conference on Utilization of Graded Aggregate Base Materials in Flexible Pavements, March 25-26, 1974, Oak Brook Hyatt House, Oak Brook, Illinois.
  • Corporate Authors:

    National Crushed Stone Association

    1415 Elliot Place, NW
    Washington, DC  United States  20007

    National Sand and Gravel Association

    900 Spring Street
    Silver Spring, MD  United States  20910

    National Slag Association

    300 South Washington Street
    Alexandria, VA  United States  22314
  • Authors:
    • Molnar, J T
  • Publication Date: 1974

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Filing Info

  • Accession Number: 00127537
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 7 1976 12:00AM