STATISTICAL CONCEPTS ON THE HIGHWAY

THE STATUS IS DISCUSSED OF THE CURRENT DISTINCTION BETWEEN NEEDS FOR ACCEPTANCE PROCEDURES BY THE HIGHWAY DEPARTMENT AND METHODS OF PRODUCT CONTROL BY THE CONTRACTOR. EMPHASIS HAS BEEN PLACED ON ESTABLISHING REALISTIC VARIANCES FOR EACH PROCESS SO THAT STATISTICAL TOLERANCES CAN REPLACE THE INTUITIVE TOLERANCES NOW BEING USED. CONTRACTORS MUST REALIZE THE NECESSITY FOR STATISTICAL CONTROL PROCEDURES. CASE HISTORIES IN VIRGINIA ARE REVIEWED ON A NON-DESTRUCTIVE TESTING PROCEDURE THAT EMPLOYS PORTABLE NUCLEAR TESTING EQUIPMENT. USING THE SMALL NUCLEAR PORTABLE GAUGE WHICH WAS DEVELOPED, A DENSITY TEST CAN BE PERFORMED ON HOT ASPHALTIC CONCRETE IN ONE MINUTE. THE METHOD INCORPORATED A RELATIVE COMPACTION PROCEDURE IN THE FIELD, USING A FIELD-ESTABLISHED STANDARD THAT ELIMINATES THE LABORATORY-TO-FIELD VARIANCE. SPECIFICATION LIMITS WERE ESTABLISHED FOR A REALISTIC ACCEPTANCE PLAN USING RANDOM TESTING. THEY SPECIFY THE NUMBER OF TESTS TO BE MADE PER LOT AS WELL AS LOT SIZE AND PROVIDE REQUIREMENTS BASED ON REALISTIC VARIANCES. CONVENTIONAL TEST RESULTS ARE COMPARED TO THE NUCLEAR TEST RESULTS. THIS COMPARISON SHOWS THE CONVENTIONAL VALUES ARE TWO TO THREE TIMES AS LARGE AS THE NUCLEAR VALUES, INDICATING THAT WITH THE SAME NUMBER OF TESTS WITH BOTH METHODS, THE NUCLEAR METHOD WILL PREDICT LOT AVERAGES MORE ACCURATELY.

  • Supplemental Notes:
    • Vol 11, No 2, PP 19-22, 1 FIG, 4 TAB, 3 REF
  • Corporate Authors:

    Quality Progress

    ,    
  • Authors:
    • Hughes, C S
  • Publication Date: 1969-2

Subject/Index Terms

Filing Info

  • Accession Number: 00215174
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 2 1994 12:00AM