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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

FRACTIONAL FACTORIAL ANALYSIS FOR FLEXIBLE PAVEMENT PERFORMANCE DATA

THE FACTORIAL EXPERIMENT WAS DESIGNED SO THAT A PROPERLY SELECTED SUBSET OF ALL THE SECTIONS COULD BE ANALYZED INDEPENDENTLY OF THE REMAINING SECTIONS. THIS SUBSET WAS CALLED A FRACTIONAL REPLICATE. IT IS SHOWN THAT A SUBSET OF A FLEXIBLE SECTION WOULD HAVE PRODUCED ESSENTIALLY THE SAME RESULTS AS AN ANALYSIS OF THE COMPLETE FACTORIAL EXPERIMENT. FRACTIONAL REPLICATE CONCEPTS ARE DESCRIBED. THE STRENGTH OF A FACTORIAL EXPERIMENT IS DUE TO THE FOLLOWING IN PART: (1) THE MAIN EFFECT OF EACH DESIGN FACTOR MAY BE ESTIMATED INDEPENDENTLY OF THE MAIN EFFECT OF EACH OTHER DESIGN FACTOR, (2) INTERACTION OF THE DESIGN FACTORS CAN BE EXAMINED, (3) THE EFFECTS CAN BE DETERMINED WITH RELATIVELY HIGH PRECISION AND EFFICIENCY SINCE ALL OF THE MEASURE DEPENDENT VARIABLES ARE USED TO ESTIMATE EACH EFFECT, AND (4) IF CERTAIN EFFECTS ARE SMALL AND NOT SIGNIFICANT THEY MAY BE USED TO ESTIMATE ERROR; THAT IS THE EFFECT OF UNCONTROLLED VARIATION. THE PRACTICE OF CONFOUNDING IS ANALYZED AND FOUND THAT IT MAY BE BENEFICIAL WHEN PROPERLY DONE. CONFOUNDING MAY BE USED FOR ONE OR TWO PURPOSES: (1) TO INDICATE MORE VARIABLES WITHOUT CHANGING THE SIZE OF THE EXPERIMENT, AND(2) TO REDUCE THE SIZE OF AN EXPERIMENT THROUGH THE USE OF FRACTIONAL REPLICATION. THE BLOCKS OR FRACTIONAL REPLICATES HAD SOME IMPORTANT CHARACTERISTICS DESIGNED INTO THEM: (1) ALL THREE LEVELS OF EACH OF THE PAVEMENT DESIGN FACTORS OCCURRED IN EACH BLOCK, (2) THE AVERAGE TOTAL PAVEMENT THICKNESS WAS THE SAME FOR EACH BLOCK IN A LOOP, (3) THREE SECTIONS WERE REPLICATED OR CONSTRUCTED IN EACH LOOP; ONE OF THESE SECTIONS WAS ASSINGED TO EACH BLOCK, (4) THE TOTAL THICKNESS OF THESE REPLICATE SECTIONS WAS EQUAL TO THE AVERAGE OF THE TOTAL THICKNESS OF THE BLOCKS, PROVIDING AN ARBITRARY RULE FOR DECIDING WHICH DESIGNS TO REPLUCATE. RESULTS SHOW THE PERFORMANCE ANALYSIS COULD HAVE MADE WITH A PROPERLY SELECTION ONE-THIRD FRACTIONAL REPLICATE OF THE FLEXIBLE PAVEMENT SECTIONS. EXPERIENCE HAS SHOWN THAT INTERACTIONS MAY BE CONCIDERED NEGLIGIBLE BECOUSE: (1) ALTHOUGH AN INTERACTION EFFECT MAY BE SIGNIFICANT EFFECT STATISTICALLY IT MAY HAVE NO PRACTICAL SIGNIFICANCE, AND (2) INTERACTION EFFECTS CAN BE DIFFICULT TO INTERPRET AND IN THE INTERESTS ROAD TEST DATA CAN BE ANALYZED BY USING ONLY A FRACTIONAL REPLICATE OF THE COMPLETE FRACTORIAL EXPERIMENT. REGIONAL ROAD TESTS COULD BE CONDUCTED ON A BLOCK BASIS WITH THE DIFFERENCES BETWEEN BLOCKS CONFOUNDED WITH THE DIFFERENCES BETWEEN REGIONS.

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  • Supplemental Notes:
    • pp 208-223, 6 FIG, 6 TAB, 12 REFDistribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
  • Corporate Authors:

    Highway Research Board

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    Transportation Research Board

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  • Authors:
    • Hain, Robert C
    • Irick, Paul E
  • Conference:
  • Publication Date: 1962

Media Info

  • Monograph Title: THE AASHO ROAD TEST - PROCEEDINGS OF A CONFERENCE HELD MAY 16-18, 1962, ST. LOUIS, MISSOURI
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00207118
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 26 1970 12:00AM