QUALITY ASSURANCE IN HIGHWAY CONSTRUCTION: QUALITY ASSURANCE OF EMBANKMENTS AND BASE COURSES-PART II

PROPER COMPACTION IS ESSENTIAL TO THE PERFORMANCE PROPERTIES OF SOIL AND ROCK MATERIAL. THE CONTROL OF THE COMPACTION PROCESS IS ONE OF THE MOST IMPORTANT ASPECTS IN BASE AND EMBANKMENT CONSTRUCTION. IT HAS BEEN DEMONSTRATED THAT NUCLEAR DENSITY MEASUREMENTS PRODUCE MORE PRECISE DATA THAN CAN BE OBTAINED BY CONVENTIONAL METHODS. VALID MEASUREMENTS OF THE ACTUAL QUALITY OF THE COMPACTION CAN BE MADE ONLY IF THE SAMPLE IS A TRUE REPRESENTATION OF THE TOTAL COMPACTED MATERIAL. THE USE OF STATISTICAL CONCEPTS TO ESTABLISH THE REQUIREMENTS OF SPECIFICATIONS AND TO AID IN THE ANALYSIS OF TEST DATA PROVIDES NEEDED IMPROVEMENT. UNIFORMITY MUST BE CONTROLLED AS WELL AS DEGREE OF COMPACTION. SEVERAL STATES HAVE DEVELOPED SPECIFICATIONS FOR EMBANKMENT OR BASE CONSTRUCTION THAT ARE IMPROVEMENTS OVER PRESENT METHODS AND ARE BASED PARTLY ON STATISTICS. VIRGINIA IS USING A CONTROL STRIP TECHNIQUE FOR CONTROL OF THE COMPACTION OF AGGREGATE BASE. THEY USED THE NUCLEAR FIELD DENSITY TESTING DEVICE, THE SPEED OF WHICH PERMITS DETERMINATION TO BE MADE FOR EACH SECTION OF MATERIAL. RESEARCH IS SHOWING THAT OVERALL STANDARD DEVIATION, A MEASURE OF VARIABILITY, IS NOT IN ITSELF A TRUE INDICATION OF CONTRACTOR-PERFORMANCE VARIABILITY. THE VARIATION IN DENSITY OF ACCEPTED EMBANKMENTS AND BASES HAS BEEN FOUND TO BE MUCH GREATER THAN EXPECTED BY THE BUREAU OF PUBLIC ROADS RESEARCH PROGRAM. IT IS CONCLUDED THAT TEST RESULTS ON BASE AND EMBANKMENT MATERIALS EXHIBIT A GREAT VARIATION. THESE VARIATIONS CAN BE ATTRIBUTED TO MATERIAL VARIANCE, SAMPLING VARIANCE, AND TO TESTING VARIANCE. STATE HIGHWAY DEPARTMENTS SHOULD TAKE STEPS TO IMPLEMENT RANDOM SAMPLING IN THE CONTROL AND ACCEPTANCE OF BASE AND ENBANKMENT CONSTRUCTION.

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  • Supplemental Notes:
    • Vol 35, No 7, PP 166-174, 11 FIG, 6 TAB, 2 PHOT, 9 REF
  • Authors:
    • McMahon, T F
  • Publication Date: 1969-4

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  • Accession Number: 00215203
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 29 1994 12:00AM