A REVIEW OF EUROPEAN PRACTICES FOR LABORATORY EVALUATION OF AGGREGATE POLISHING CHARACTERISTICS

EUROPEAN METHODS OF EVALUATING AGGREGATE POLISHING ARE PRESENTED. THE BRITISH ARE CONTINUING THEIR INVESTIGATIONS FOR A BETTER NON-SKID SURFACING AND SPECIAL TYPES OF MANUFACTURED AGGREGATES. CALCINED BAUXITE WAS MEASURED BY THE BRITISH PENDULUM TESTER AND SIDEWAYS FORCE COEFFICIENT APPARATUS, AND FOUND TO HAVE A POLISHED STONE VALUE OF 75, WHICH IS BETTER THAN THE BEST NATURAL ROADSTONE. HOWEVER, IT IS TOO EXPENSIVE ($75/TON USABLE MATERIAL) FOR PRACTICAL USE. THE RESEARCHERS HOPE TO FIND A MANUFACTURED AGGREGATE MADE UP OF A MATRIX CONTAINING HARD AND ANGULAR GRANULES OF ANOTHER MATERIAL. THE ROAD SURFACE TEXTURE SHOULD BE ROUGH. STEREOPHOTOGRAPHIC TECHNIQUES WITH COMPUTER ANALYSIS GIVE THE TEXTURE MEASUREMENTS. THE ROAD RESEARCH LABORATORY AND CEMENT AND CONCRETE ASSOCIATION DEVELOPED AN ACCELERATED WEAR MACHINE, ACTUALLY AN ENLARGED VERSION OF THE STONE POLISHING APPARATUS, FOR STUDYING PORTLAND CEMENT PAVING MIXTURES. FOR SURFACE TEXTURE MEASUREMENTS, THE FRENCH MAKE A RUBBER CASTING OF THE SURFACE TO MAKE A REPLICATE OF THE SURFACE IN EPOXY RESIN. THE PROFILE RATIO IS MEASURED AND ANALYZED BY COMPUTER. THE BRITISH STONE POLISHING TEST IS USED FOR AGGREGATE EVALUATION AND FOUND TO HAVE GOOD CORRELATION BETWEEN THE POLISHING CHARACTERISTICS AND THE VICKERS HARDNESS TEST. FOR PORTLAND CEMENT PAVEMENTS THE FRENCH ADVOCATE MECHANICAL BRUSHING IN TRANSVERSE DIRECTION FOR SURFACE LAITANCE REMOVAL AND CHOOSING A NON-POLISHING MORTAR. THE BELGIAN TECHNIQUE FOR TEXTURING PORTLAND CEMENT LIES IN INCORPORATING TRANSVERSE GROOVES IN FRESH CONCRETE. IN GERMANY, PROFILE MEASUREMENTS ARE MADE WITH A RUBBER-COATED STYLUS. THIS METHOD IS BELIEVED TO TAKE INTO ACCOUNT THE MICROROUGHNESS OF PAVEMENT SURFACES. SINCE THE GERMANS BELIEVE THAT ACCIDENT STATISTICS ARE THE MOST IMPORTANT PARAMETER WHEN JUDGING THE NEED FOR RESURFACING TO IMPROVE RESISTANCE TO SKIDDING, ACCIDENT DATA ARE COLLECTED TO SPOT LOCATIONS WHERE SKIDDING ACCIDENTS OCCURRED AND TO INVESTIGATE THE SKIDDING CHARACTERISTICS OF THESE PAVEMENTS.

Media Info

  • Media Type: Print
  • Pagination: pp 15-17
  • Monograph Title: Aggregates and skid resistance of bituminous pavements
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00211610
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 8 1971 12:00AM