CRACKING OF ASPHALTIC CONCRETE ADJACENT TO TRAFFIC STRIPES

IT IS WELL KNOWN THAT CERTAIN SECTIONS OF ASPHALTIC CONCRETE ROADS HAVE DEVELOPED SEVERE CRACKING ADJACENT TO THE TRAFFIC STRIPE. PRELIMINARY INVESTIGATION OF THIS PROBLEM INDICATED THAT THE TRAFFIC STRIPE WAS CONSIDERABLY HARDER AND MORE COHESIVE THAN THE ROAD SURFACE, PARTICULARLY AT 140 F, AND THIS WAS BELIEVED TO BE A FACTOR IN THE CRACKING PROBLEM. THE DIFFERENCE IN HARDNESS WAS MEASURED BY A MODIFICATION OF THE PENETROMETER USED FOR DETERMINING THE HARDNESS OF BITUMENS. A VARIETY OF TRAFFIC PAINTS WAS TESTED IN THE LABORATORY ON SLABS OF TYPICAL SAND-ASPHALT AND SAND- ASPHALT-AGGREGATE MIXES. IN ALL CASES THE HARDNESS OF THE COMPOSITION WAS GREATER OVER THE TRAFFIC STRIPE THAN OVER THE COMPOSITION ITSELF. THE DIFFERENCE IN HARDNESS INCREASED WITH RISE IN TEMPERATURE AND WAS PARTICULARLY EVIDENT AT 140 F. THE SLABS WERE SUPPORTED ON A 20-GAGE STEEL PANEL AND THE ASSEMBLY WAS FLEXED SLIGHTLY AT 140 F TO SIMULATE THE ACTION OF MOVING TRAFFIC. FLEXING WAS CONTINUED UNTIL CRACKS DEVELOPED; IN ALL CASES THE CRACKS WERE ADJACENT TO THE TRAFFIC STRIPE. THE CRACKS FOLLOWED THE STRIPE CLOSELY IN THE SAND-ASPHALT MIXES AND WHEN AGGREGATE WAS ADDED, THE CRACK WENT AROUND ANY AGGREGATE PARTICLE DIRECTLY UNDER THE EDGE OF THE STRIPE. TESTS WITH AN EXPERIMENTAL THERMOPLASTIC TRAFFIC PAINT MADE TO HAVE LOW COHESIONAL STRENGTH SHOWED THAT CRACKING DEVELOPED AT LINES OF WEAKNESS IN THE SLAB AND NOT ADJACENT TO THE TRAFFIC STRIPE. NO TESTS WERE MADE TO DETERMINE THE DURABILITY OF THIS PAINT UNDER SERVICE CONDITIONS. THIS INVESTIGATION HAS SHOWN THAT THE DIFFERENCE IN HARDNESS AND COHESIONAL STRENGTH OF ASPHALTIC CONCRETE AND THIS MATERIAL COATED WITH CONVENTIONAL TRAFFIC PAINTS IS A MAJOR FACTOR IN THE CRACKING WHICH OCCURS ADJACENT TO THE TRAFFIC STRIPE. INASMUCH AS CRACKING OCCURS IN CERTAIN LOCATIONS AND NOT IN OTHERS WHEN THE SAME PAINT IS USED, IT IS APPARENT THAT VARIATIONS IN ROAD COMPOSITION OR STRUCTURE ARE CONTRIBUTING FACTORS. ADDITIONAL STUDIES ARE BEING MADE OF THE ROAD STRUCTURE AND SPECIAL TRAFFIC PAINTS TO OBTAIN FURTHER INFORMATION ON THIS PROBLEM. /AUTHOR/

  • Supplemental Notes:
    • Vol 38, pp 356-366, 7 FIG, 5 TAB, 1 REF
  • Authors:
    • Payne, H F
    • Bransford, T L
    • Gartner, W
  • Publication Date: 1959

Media Info

  • Monograph Title: Proceedings of the Thirty-Eighth Annual Meeting of the Highway Research Board, Washington, D.C., January 5-9, 1959
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00207355
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 27 1971 12:00AM