CONTROL OF MATERIALS AND MIXTURES FOR CONCRETE FOR PAVEMENTS

THE METHODS USED BY THE IOWA HIGHWAY COMMISSION TO CONSTRUCT 700 MILES OF CONCRETE PAVEMENT IN 1928 TO INSURE CONCRETE OF UNIFORM QUALITY CONTAINING A QUANTITY OF CEMENT WITHIN ONE PERCENT OF THAT ESTIMATED IN THE SPECIFICATIONS ARE DESCRIBED. METHODS FOR FIELD DETERMINATION OF THE FACTORS NEEDED FOR MAINTANING ACCURATE MEASUREMENT OF MATERIALS, SUCH AS SPECIFIC GRAVITY, CONTAINED MOISTURE, AND ABSORPTION OF AGGREGATES, ARE GIVEN. METHODS AND APPLIANCES FOR WEIGHING AGGREGATES AND MEASURING WATER ARE DISCUSSED. RESULTS ARE EVALUATED BY MEANS OF TRANSVERSE TESTS MADE IN THE FIELD, COMPRESSIVE TESTS OF CYLINDERS AND CORES AND DAILY RECORDS OF QUANTITIES OF MATERIALS USED. THE AVERAGE OVER-RUN IN CEMENT USED FOR ALL JOBS WAS 1.2 PERCENT AND 52 PERCENT OF THE ENTIRE MILEAGE WAS WITHIN 1.0 PERCENT OF THE ESTIMATED QUANTITY OF CEMENT. AS THESE FIGURES INCLUDE THE OVER-RUNS DUE TO EXTRA DEPTH OF SLAB, THE OBJECTIVE WAS SUBSTANTIALLY ATTAINED. THE STRENGTH TESTS SHOW MARKED IMPROVEMENT IN UNIFORMITY. RANGE IN AVERAGE STRENGTH OF JOBS-COMPRESSION AGE 28 DAYS - MAXIMUM 5,404, AVERAGE 4,538, MINIMUM 3,732 LBS PER SQUARE INCH; TRANSVERSE AGE 10 DAYS, MAXIMUM 725, AVERAGE 600, MINIMUM 454 LBS. PER SQUARE INCH. THE MEAN VARIATION FROM THE AVERAGE OF STRENGTHS OF INDIVIDUAL SPECIMENS FOR THE VARIOUS JOBS RANGED FROM 4.6 PERCENT TO 17.8 PERCENT FOR TRANSVERSE AND FROM 4.7 PERCENT TO 17.2 PERCENT FOR COMPRESSION TESTS. THESE FIGURES ARE SHOWN IN COMPARISON WITH CORRESPONDING DATA FROM EARLIER TESTS UNDER MUCH LESS COMPLETE METHODS OF CONTROL. EFFECTS OF DIFFERENT PROPORTIONS AND KINDS OF AGGREGATE, AND RELATIONS BETWEEN TRANSVERSE AND CRUSHING STRENGTHS, AS INDICATED BY THESE DATA, ARE DISCUSSED.

  • Supplemental Notes:
    • Vol 9, pp 276-330, 26 FIG, 7 TAB
  • Authors:
    • Crum, R W
    • Jackson, F H
    • Scholer, C H
  • Discussers:
    • Myers, B
  • Publication Date: 1930

Media Info

  • Monograph Title: Proceedings of the Ninth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 12-13, 1929
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00205819
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 1 1971 12:00AM