NEW IDEAS IN ASPHALT ROAD CONSTRUCTION

REGINA, CANADA, HAS A TREMENDOUS SURPLUS OF SAND AND SHORTAGE OF ROCK. BECAUSE OF THIS FACT, WAYS WERE INVESTIGATED OF UTILIZING SAND AND CONSERVING ROCK. IF SANDS ARE STABILIZED WITH PORTLAND CEMENT AS IN SOIL CEMENT OR WITH ASPHALT BITUMEN IN ASPHALTIC CONCRETE, THEY CAN PERFORM A VERY USEFUL FUNCTION. ADVANTAGES OF HOT MIX ASPHALT BASE WERE REVIEWED. FROM THE POINT OF CEMENT COSTS, IT IS OBVIOUS THAT PENETRATION GRADE ASPHALT CEMENT AS USED IN HOT MIX ASPHALT BASE IS CHEAP AND HAS A DISTINCT COST ADVANTAGE IN SASKATCHEWAN. HOT MIX ASPHALT BASE CAN BE LAID IN COLDER WEATHER AND NOT BE SUBJECT TO DAMAGE. SOIL CEMENT REQUIRES TWO DAYS FROST FREE CURING AND SEVEN DAYS CURING BEFORE LOADING. SOIL CEMENT REQUIRES A SURFACE OF ASPHALT CONCRETE TO PROVIDE A WEARING SURFACE. THEREFORE, A SOIL CEMENT CONTRACT REQUIRES BOTH SOIL CEMENT EQUIPMENT AND ASPHALT EQUIPMENT, WHEREAS HOT MIX ASPHALT BASE AND SURFACE COURSE IS MADE IN THE SAME PLANT. BY PUTTING HOT MIX ASPHALT DIRECTLY ON PREPARED SUB GRADE, THE NUMBER OF OPERATIONS ARE CUT DOWN AND, THEREFORE, THE TIME EXPOSED TO ADVERSE WEATHER IS REDUCED. IT IS SUGGESTED THAT THE DESIGN OF BASE AND CURBS BE MODIFIED TO ALLOW THE FOLLOWING SEQUENCE: (1) EXCAVATION, (2) SUB GRADE PREPARATION AND COMPACTION, (3) LAYDOWN FIRST LIFT OF HOT MIX ASPHALT BASE ON CLAY SUB GRADE SO THAT IT EXTENDS UNDER THE AREA THAT THE CURB SITS ON, (4) CONSTRUCT CURB AND GUTTER ON TOP OF FIRST LIFT OF ASPHALT BASE, AND (5) FINISH FINAL LIFT OF ASPHALT BASE COURSE. BY PLACING CURBS ON PREPARED ASPHALT BASE, EITHER SLIP FORMED MACHINES LAID CONCRETE CURBS CONSTRUCTION PROCEDURES COULD BE USED OR PRECAST CURBS COULD BE LAID, SAVING TIME NORMALLY USED IN SETTING AND MOVING FORMS AND IN FINISHING CONCRETE. IT IS SUGGESTED THAT BY FLOODING THE ASPHALT CONCRETE MIX WITH INERT GASES DURING PRODUCTION, THE HIGH RATE OF OXIDATION OF THE ASPHALT CEMENT WHICH OCCURS DURING PRODUCTION COULD BE RETARDED.

• Supplemental Notes:
  • pp 5-6, 10, 1 PHOT
• Authors:
  • Clapson, L L
• Publication Date: 1969-6

Media Info

• Serial:
  • Paving Forum /Napa/

Subject/Index Terms

• TRT Terms: Asphalt cement; Asphalt concrete; Bituminous aggregates; Bituminous construction; Curbs; Drains; Economics; Hot mix asphalt; Noble gases; Oxidation; Sand; Soil cement; Subgrade (Pavements)
• Old TRIS Terms: Oxidation reduction
• Subject Areas: Construction; Economics; Highways; Materials;

Filing Info

• Accession Number: 00211446
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 29 1994 12:00AM