DENSITY CONTROL: ITS BENEFITS AND COMPLEXITIES

TEXAS EMPLOYS THE COMPACTION RATIO (THE RATION OF THE DIFFERENCE BETWEEN ROADWAY AS COMPACTED DENSITY (D SUB A) AND THE LOOSE DRY WEIGHT OF THE SOIL (D SUB L) DETERMINED BY THE TEXAS METHOD TO THE DIFFERENCE BETWEEN THE MAX. LABORATORY DENSITY (D SUB D) UNDER A COMPACTIVE EFFORT OF 30 FT-LB/CU IN.). THE METHOD RESULTS IN HIGH DENSITY REQUIREMENTS FOR NON-SWELLING SOILS AND LOWER, MORE SUITABLE DENSITIES FOR SWELLING SOILS. SOILS AND BASE MATERIALS ARE PLACED IN THREE GROUPS: UNIFORM, NONUNIFORM AND ERRATIC DEPENDING ON THE RELATION OF THEIR RESPECTIVE VALUES TO THE D SUB A DENSITY. PLOTS ARE MADE OF THE DEVIATION FROM AVERAGE D SUB A VS PERCENT OF AVERAGE D SUB A REPRESENTING THE THREE TYPES OF MATERIAL. REASONABLE COMPACTION RANGES ARE ESTABLISHED FOR EACH GROUP FOR USE AS A BASIS FOR CONTROL. DESIGN AND CONSTRUCTION RECOMMENDATIONS HAVE BEEN PREPARED FOR DIFFERENT TYPES OF SOIL AND FOR SOME SOILS CONTAINING ADMIXTURES OF STABILIZING AGENTS. USE IS MADE OF THE TEXAS GYRATORY METHOD FOR ERRATIC MATERIALS. DATA HAVE SHOWN THAT INCREASING COMPACTIVE EFFORT FROM 4 TO 30 FT-LB/ CU IN. INCREASED DENSITY OF A SANDY SOIL BY 9 PCF AND INCREASED THE SHEARING RESISTANCE FROM 19 TO 30 PSI (FOR 20 PSI NORMAL STRESS). THE PAPER CONCLUDES THAT THE COMPACTION RATIO METHOD ESTABLISHES THE DEGREE OF DENSITY THAT IS REQUIRED AND THAT IS PRACTICAL, THAT THE RESULTS OF HIGH COMPACTIVE EFFORT TESTS ARE MORE NEARLY REPRODUCIBLE THAN THOSE FOR LOWER EFFECTS, THAT DENSITY CONTROL OF ERRATIC MATERIALS IS WISHFUL THINKING AND THAT THE TEXAS GYRATORY COMPACTOR OFFERS GOOD PROMISE FOR MEASURING DENSITY PROPERTIES. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1967/177/177-013.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Compaction and presented at the 46th Annual Meeting. 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.
• Authors:
  • McDowell, Chester
• Publication Date: 1967

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 197-209
• Monograph Title: Symposium on Compaction of Earthwork and Granular Bases
• Serial:
  • Highway Research Record
  • Issue Number: 177
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Base course (Pavements); Compaction; Construction; Density; Design; Laboratory tests; Ratios; Soils; Weight
• Uncontrolled Terms: Gyratory compaction
• Old TRIS Terms: Bases; Dry weight
• Subject Areas: Construction; Design; Geotechnology; Highways;

Filing Info

• Accession Number: 00214677
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Feb 2 1994 12:00AM