AIRPORT RUNWAY EVALUATION IN CANADA PART II, WITH DISCUSSION

COMPACTING A CLAY SUBGRADE TO 95 PERCENT MODIFIED AASHO MAXIMUM DENSITY DEVELOPED A GREATER SUPPORTING VALUE THAN THAT OF THE UNCOMPACTED SUBGRADE AT 85 PERCENT MODIFIED AASHO. THE INCREASE IN BEARING CAPACITY PROVIDED BY THE FIRST 12-INCH LAYER OF COMPACTED SOIL WAS CONSIDERABLY GREATER THAN THAT GIVEN BY AN ADDITIONAL 12-INCH COMPACTED LAYER. SUBGRADE COMPACTION IN THE FIELD APPEARS TO CAUSE THE FIELD CBR AND CONE BEARING RATINGS OF THE SUBGRADE TO INCREASE AT A CONSIDERABLY FASTER RATE THAN THE ACTUAL SUPPORTING VALUE AS MEASURED BY THE PLATE BEARING TEST. THE HOUSEL PENETROMETER VALUE IS AFFECTED IN THIS MANNER TO A LESS SERIOUS DEGREE, WHILE THE TRIAXIAL TEST SEEMS TO MORE NEARLY PARALLEL THE INCREASE INDICATED BY THE PLATE BEARING TEST. A SIMPLE EQUATION IS PRESENTED FOR CALCULATING THE SUBGRADE MODULUS AT THE SURFACE OF ANY GIVEN THICKNESS OF WELL COMPACTED GRANULAR BASE COURSE, IF THE SUBGRADE MODULUS FOR THE UNDERLYING SUBGRADE HAS BEEN DETERMINED. THE VALUE OF K IN THE FLEXIBLE PAVEMENT DESIGN EQUATION T=K LOG (P/S) HAS BEEN FOUND TO BE DEPENDENT UPON THE SIZE OF BEARING PLATE EMPLOYED, WHEN ALL OTHER VARIABLES ARE CONSTANT. THIS HAS RESULTED IN SOME MODIFICATION OF THE PAVEMENT THICKNESS DESIGN CHARTS FOR AIRPORTS AND HIGHWAYS CONTAINED IN THE PAPER PRESENTED AT THE 1946 ANNUAL MEETING. A METHOD FOR SELECTING BASE COURSE MATERIALS AND DESIGNING FLEXIBLE WEARING COURSE MIXTURES BY MEANS OF THE TRIAXIAL COMPRESSION TEST IS OUTLINED. /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrbresearchrpts/1947/4B47Sup.pdf
• Supplemental Notes:
  • Distribution, 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:

  Transportation Research Board

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• Authors:
  • McLeod, Norman W
  • Boyd, W K
  • Foster, C R
• Publication Date: 1948

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 87p
• Serial:
  • Highway Research Board Research Reports
  • Issue Number: 5B
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Airport runways; Base course (Pavements); Bearing capacity; Coefficient of subgrade reaction; Compression; Flexible pavements; Mix design; Pavement design; Pavements; Soil compaction; Subgrade (Pavements); Thickness; Wearing course (Pavements)
• Uncontrolled Terms: Pavement thickness; Triaxial compression
• Subject Areas: Aviation; Geotechnology; Highways; Pavements; Terminals and Facilities;

Filing Info

• Accession Number: 00207400
• Record Type: Publication
• Report/Paper Numbers: No. 4B-1948 Supplement
• Files: TRIS, TRB
• Created Date: May 22 1972 12:00AM