DISCUSSION OF PROGRESS REPORT ON LOWCOST IMPROVED ROADS INVESTIGATION

THE NEED WAS EMPHASIZED FOR THE DEVELOPMENT OF LOW-COST IMPROVED ROADS. SOUTH CAROLINA HAS EXPERIMENTED WITH SEVERAL DIFFERENT METHODS, INCLUDING THE USE OF CALCIUM CHLORIDE AND SULPHITE LIQUOR AS DUST LAYER, AND BITUMINOUS TREATMENTS. THE BEST RESULTS WERE OBTAINED WITH A DOUBLE- SURFACE BITUMINOUS TREATMENT USING TAR SUITABLE FOR COAL APPLICATION AND ASPHALTIC OIL AS A COVER COAT WITH CRUSHED STONE AS THE STABILIZER. THE METHOD OF TREATMENT IS DESCRIBED AS FOLLOWS: (1) SCARIFY THE OLD ROAD SURFACE, ADD NEW SURFACING MATERIAL AS NEEDED, ROAD MACHINE TO STANDARD CROSS-SECTION AND THEN MAINTAIN CAREFULLY UNDER TRAFFIC UNTIL THE ROAD SURFACE IS SMOOTH AND WELL BONDED, (2) WHILE DRY AND BEFORE WAVES HAVE A CHANCE TO DEVELOP, SWEEP ALL LOOSE MATERIAL FROM THE ROAD SURFACE AND APPLY TAR SUITABLE FOR COAL APPLICATION WITH VISCOSITY 8 TO 13 AT 40 DEGREES C., (3) AFTER THE TAR HAS HAD 24 HOURS TO PENETRATE, HEATED ASPHALT OF 150 TO 200 PENETRATION IS APPLIED, (4) THE ASPHALT COAT IS IMMEDIATELY COVERED WITH CRUSHED STONE, (5) THE ROAD IS OPEN TO TRAFFIC AND THE SURFACE AFTER A FEW MONTH'S EXPOSURE GRADUALLY CHANGES ITS APPEARANCE FROM A PLAIN CRUSHED STONE SURFACE TO A BITUMINOUS SURFACE WITH MANY EXPOSED STONES, AND (6) THE SURFACE IS THEN GIVEN A SEAL COAT OF A RATHER LIGHT ASPHALTIC OIL. THE ORIGINAL COST OF THIS TREATMENT IS ABOUT $2000 PER MILE FOR A TREATED WIDTH OF 20 FEET. ROADS TREATED IN THIS WAY ARE CARRYING 1500 VEHICLES PER DAY IN A SATISFACTORY MANNER. MAINTENANCE COSTS ARE ABOUT $400 PER MILE FOR THE FIRST YEAR AND ABOUT $300 PER YEAR FOR THE SECOND AND THIRD YEARW.

  • Supplemental Notes:
    • Vol 6, pp 391-393
  • Authors:
    • Moorefield, C H
  • Publication Date: 1927

Media Info

  • Monograph Title: Proceedings of the Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C., December 2-3, 1926
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00218614
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 11 1971 12:00AM