RELATIONSHIPS BETWEEN DENSITY, BITUMEN CONTENT, AND VOIDS PROPERTIES OF COMPACTED BITUMINOUS PAVING MIXTURES

BECAUSE IT WOULD LEAD TO A BETTER UNDERSTANDING OF THE DESIGN AND PERFORMANCE OF BITUMINOUS PAVEMENTS, THIS PAPER ADVOCATES DESIGNING BITUMINOUS PAVING MIXTURES ON A VOLUMETRIC BASIS IN PLACE OF THE COMMON CURRENT PRACTICE OF DESIGNING THEM ON THE BASIS OF WEIGHT. COARSE AND FINE AGGREGATE COMBINATIONS THAT TEND TO BE TOO DENSELY GRADED PRESENT THE MOST SERIOUS PROBLEM CONCERNING THE DESIGN OF BITUMINOUS PAVING MIXTURES IN CANADA. DATA ARE INCLUDED SHOW THAT THESE DENSELY GRADED AGGREGATES CAN BE OPENED UP BY INCREASING THE PERCENTAGE OF FINE AGGREGATE. SINCE THE ADDITION OF MINERAL FILLER FURTHER DECREASES THE VOID SPACE IN A MINERAL AGGREGATE THAT MAY ALREADY BE TOO DENSELY GRADED, TEST DATA ARE PRESENTED TO DEMONSTRATE THAT MINERAL FILLER SHOULD NOT BE ADDED TO DENSE GRADED BITUMINOUS PAVING MIXTURES UNLESS ACTUAL LABORATORY TESTS INDICATE THAT IT WILL SERVE SOME USEFUL PURPOSE. THE MAGNITUDE OF THE ERRORS IN VALUES REPORTED FOR "PERCENT VOIDS IN THE MINERAL AGGREGATE," "PERCENT AIR VOIDS," AND "PERCENT VOIDS FILLED WITH BITUMEN," FOR COMPACTED PAVING MIXTURES MADE WITH AGGREGATES THAT ABSORB CONSIDERABLE BITUMEN, IS POINTED OUT WITH EXAMPLES. OTHER EXAMPLES SHOW THAT SIGNIFICANT ERRORS IN THESE VALUES OCCUR EVEN FOR AGGREGATES OF RELATIVELY LOW BITUMINOUS ABSORPTION. THESE EXAMPLES DEMONSTRATE THAT THE ERRORS IN VOIDS VALUES CAN BE SO SERIOUS THAT SOME SUITABLE METHOD SHOULD BE EMPLOYED TO DETERMINE THE QUANTITY OF BITUMEN ABSORBED BY ANY AGGREGATE PROPOSED FOR USE IN A PAVING MIXTURE. THE PURPOSE IS TO PRESENT A NUMBER OF SIMPLE CHARTS THAT CONTAIN FAMILIES OF CURVES RELATING THE FIVE VARIABLES--CORRECTED DENSITY, CORRECTED BITUMEN CONTENT, PERCENT VOIDS IN THE MINERAL AGGREGATE, PERCENT AIR VOIDS, AND PERCENT VOIDS FILLED WITH BITUMEN. THE ORDINATE OF THESE CHARTS IS CORRECTED DENSITY, AND THE ABSCISSA IS CORRECTED BITUMEN CONTENT, SINCE THE DENSITY AND BITUMEN CONTENT OF A COMPACTED PAVING MIXTURE ARE USUALLY MEASURED DIRECTLY. SINCE THE DESIGN REQUIREMENTS FOR A PAVING MIXTURE CAN BE REPRESENTED BY A SMALL AREA ON ONE OF THESE CHARTS, THEIR USE SHOULD LEAD TO BETTER UNDERSTANDING OF THE DESIGN, INSPECTION, AND CONTROL OF BITUMINOUS PAVING MIXTURES. COMPACTION REQUIREMENTS SPECIFIED FOR THE FINISHED PAVEMENT CAN ALSO BE LOCATED ON THESE DIAGRAMS. THESE CHARTS HAVE THE OUTSTANDING ADVANTAGE THAT THE PLOTTING OF THE POINT REPRESENTING BITUMEN CONTENT AND DENSITY FOR A COMPACTED MIXTURE ENABLES VALUES FOR PERCENT VOIDS IN THE MINERAL AGGREGATE, PERCENT AIR VOIDS, AND PERCENT VOIDS FILLED WITH BITUMEN TO BE READ DIRECTLY FROM THE CHART BY INTERPOLATION, WITHOUT THE USUAL NEED FOR CALCULATING THEM. /AUTHOR/

  • Supplemental Notes:
    • Vol 35, pp 327-404, 52 FIG, 5 TAB, 10 REF, 1 APP
  • Authors:
    • Mcleod, N W
  • Publication Date: 1956

Media Info

  • Monograph Title: Proceedings of the Thirty-Fifth Annual Meeting of the Highway Research Board, Washington, D.C., January 17-20, 1956
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00211635
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 1971 12:00AM