THE CONTROL OF VOIDS IN AGGREGATES FOR BITUMINOUS PAVING MIXTURES

BITUMINOUS PAVING MIXTURES SHOULD BE DESIGNED TO CONTAIN SUFFICIENT AIR VOIDS SO THAT AFTER ULTIMATE COMPACTION IN THE FIELD SOME VOIDS WILL STILL REMAIN. COMPLETE DENSIFICATION IS TO BE PREVENTED SINCE THIS CONDITION ACCENTUATES THE LUBRICATING ACTION OF THE ASPHALT WITH CONSEQUENT LOSS OF STABILITY. EXPERIENCE HAS SHOWN THAT RUTTING AND SHOVING ARE ASSOCIATED WITH VERY DENSE MIXTURES EVEN WHEN THE ASPHALT CONTENT IS COMPARATIVELY LOW. THE RELATIONSHIP BETWEEN LABORATORY AND ULTIMATE FIELD DENSITY HAS NOT BEEN ESTABLISHED THOROUGHLY. HOWEVER, THE CORPS OF ENGINEERS HAS SHOWN THAT, IN ORDER TO PREVENT OVER DENSIFICATION IN THE FIELD WITH WHEEL LOADS CARRIED ON TIRES INFLATED TO 100 PSI PRESSURE, THE LABORATORY SAMPLES MUST CONTAIN MINIMUM AIR VOIDS OF ABOUT THREE PERCENT, WHEN COMPACTED WITH 50 BLOWS OF THE MARSHALL HAMMER. THE PROVISION OF SUFFICIENT VOIDS IN COMPACTED BITUMINOUS MIXTURES CONSTITUTES A PROBLEM, SINCE EXPERIENCE SHOWS THAT THE TENDENCY IS FOR THE VOIDS TO BE VERY LOW IN WELL GRADED MIXTURES CONTAINING ENOUGH ASPHALT TO RENDER THEM DURABLE. BECAUSE OF THIS TENDENCY, ONE OF TWO THINGS MUST BE DONE TO PROVIDE DESIRED VOIDAGE. EITHER THE AGGREGATE MUST BE MADE LESS DENSE, OR THE ASPHALT CONTENT MUST BE REDUCED.

• Supplemental Notes:
  • Vol 26, pp 297-311
• Authors:
  • Campen, W H
  • Smith, J R
  • Erickson, L G
  • Mertz, L R
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1957

Subject/Index Terms

• TRT Terms: Aggregates; Air voids; Asphalt content; Bituminous mixtures; Compaction; Control; Densification; Field density; Plastic deformation; Stability (Mechanics); Tires; Void ratios; Wheel loads
• Old TRIS Terms: Air voids content; Void
• Subject Areas: Geotechnology; Highways; Materials; Vehicles and Equipment;

Filing Info

• Accession Number: 00210995
• Record Type: Publication
• Source Agency: Highway Research Board Bibliography
• Files: TRIS
• Created Date: Apr 21 1994 12:00AM