PART II. CHANGES IN BITUMEN COMPOSITION CAUSING CHANGES IN VISCOSITY

AN EXAMINATION HAS BEEN MADE OF EXPERIMENTAL SURFACINGS LAID ON A HEAVILY TRAFFICKED ROAD. THESE COMPRISED ASPHALTIC CONCRETE SECTIONS USING REFINERY BITUMEN AND FLUXED TRINIDAD LAKE ASPHALT AS BINDERS, AND ROLLED ASPHALT SECTIONS USING REFINERY BITUMENS FROM TWO DISTINCT CRUDE SOURCES. THE CHANGES IN VISCOSITY HAVE BEEN DETERMINED FOR THE BITUMEN RECOVERED FROM THE UPPER-MOST LAYER OF THE EXPERIMENTAL SURFACINGS AND IN SUCCESSIVE 0.5-MM LAYERS OF THE ROLLED ASPHALT SECTIONS. CORRESPONDING CHANGES IN COMPOSITION HAVE BEEN DETERMINED BY A NEWLY DEVELOPED SOLVENT FRACTIONATION TECHNIQUE. IMPORTANT FACTORS IN THE BEHAVIOR OF BINDER IN SURFACE LAYERS ARE CHANGES IN CONSTITUTION BROUGHT ABOUT BY ATMOSPHERIC OXIDATION AND BY ABSORPTION OF OIL DROPPED FROM VEHICLES. THE INTERACTION OF HARDENING BY OXIDATION AND SOFTENING BY OIL DROPPINGS HELPS EXPLAIN WHY THE NATURE OF THE BINDER PLAYS AN IMPORTANT ROLE IN DETERMINING THE RESISTANCE TO SKIDDING OF DENSE BITUMINOUS SURFACINGS. A CORRELATION HAS BEEN ESTABLISHED BETWEEN THE COMBINED EFFECTS OF WEATHER AND TRAFFIC, THE CHANGE IN PROPERTIES OF THE BINDERS IN THE SURFACE LAYERS, AND THE SURFACE TEXTURE AND SKIDDING RESISTANCE. /AUTHOR/

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  • Accession Number: 00210309
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Nov 7 1994 12:00AM