INFLUENCE OF AGGREGATE SHAPE ON ENGINEERING PROPERTIES OF ASPHALTIC PAVING MIXTURES

THE FOLLOWING POPERTIES CHARACTERIZE FLAKY AGGREGATES AS OPPOSED TO CUBICAL AGGREGATES: (A) TENDENCY TO STRATIFY (LOWEST ENERGY LEVEL) (B) LOW COMPACTIBILITY, (C) LARGER SPECIFIC SURFACE AREA FOR THE SAME FRACTION, AND (D) HIGHER BREAKAGE VALUE (LOWER MOMENT OF INERTIA). THESE PROPERTIES MAY BE EXPECTED TO PRODUCE THE FOLLOWING CHARACTERISTICS IN ASPHALTIC MIXTURES: (A) WEAKNESS PLANES, WHICH FAVOR A LOW LOAD-CARRYING CAPACITY AND STRENGTH ANISOTROP; (B) LOW DENSITY; (D) HIGH OPTIMAL BITUMEN CONTENT; AND (D) HIGH BREAKAGE VALUE, WHICH DISTORTS THE ORIGINAL GRADING AND CAUSES THE FORMATION OF VOIDS FREE OF BITUMEN OR FINES, THEREBY REDUCING THE LOAD-CARRYING CAPACITY STILL FURTHER. THE SUBJECT WAS INVESTIGATED WITH THE AID OF A LITERATURE SURVEY ON THE INFLUENCE OF AGGREGATE SPHERICITY ON THE ENGINEERING PROPERTIES OF ASHALTIC MIXTURES AND LABORATORY TESTS DESIGNED TO GIVE A RELIABLE PICTURE OF AGGREGATE BEHAVIOR IN PAVEMENTS. THE INFLUENCE OF AGGREGATE SPHERICITY IN THE EXTREME CASES OF ASPHALTIC MIXTURES IS CHARACTERIZED BY DENSE AND OPEN GRADINGS, I.E., SOLID MASS AND MINIMUM VOID PERCENTAGE RESPECTIVELY. THE CONCLUSION, WHICH OCCASIONALLY CONTRADICTS THE FINDINGS OF OTHERS, IS THAT FLAKEY AGGREGATES (SPECIFICALLY THE HARD, CRUSHED TYPE USED IN LABORATORY STUDIES) MAY BE REGARDED AS A CONVENTIONAL MATERIAL FROM THE ENGINEERING VIEWPOINT, I.E., THAT THEY MAY BE USED FOR PRODUCING ASPHALTIC MIXTURES. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1972/404/404-005.pdf
• Supplemental Notes:
  • Sponsored by Committee on Characteristics of Aggregates and Fillers for Bituminous Construction. 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:
  • Livneh, Moshe
  • Greenshtein
• Conference:
  • 51st Annual Meeting of the Highway Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1972-1-17 to 1972-1-21
• Publication Date: 1972

Media Info

• Media Type: Print
• Features: Appendices; Figures; References; Tables;
• Pagination: pp 42-56
• Monograph Title: Asphalt mixture characterization and asphalt grading
• Serial:
  • Highway Research Record
  • Issue Number: 404
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Aggregates; Asphalt; Asphalt mixtures; Bitumen; Compactibility; Density; Fracture mechanics; Reviews; Shape; Stratification
• Uncontrolled Terms: Sphericity
• Old TRIS Terms: Aggregate characteristics; Flakes
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00211772
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Apr 2 1973 12:00AM