PERFORMANCE OF MODIFIED TARS CONTAINING COAL AND POLYMER

A PROGRAM WAS CONDUCTED TO TEST THE PERFORMANCE OF MODIFIED TARS IN SMALL-SCALE AND FULL-SCALE ROAD EXPERIMENTS. THE COAL WAS INCORPORATED IN THE TAR IN A PILOT PLANT, THE AMOUNT OF COAL ADDED VARYING BETWEEN EIGHT AND TWELVE PERCENT. THE POLYMER WAS ADDED WHERE REQUIRED ON THE JOB, IMMEDIATELY BEFORE USE, THE COPOLYMERS TESTED BEING BUTADIENE AND ACRYLONITRILE AND BUTADIENE AND STYRENE, BOTH AT 0.5 AND 1.0 PERCENT. THE MODIFIED TARS WERE TESTED IN SINGLE RESEALING, SURFACE TREATMENTS FOR NEW CONSTRUCTION AND IN PREMIX SURFACINGS. MODIFIED TARS CONTAINING COAL AND POLYMER PERFORMED VERY WELL IN SINGLE RESEALING AND IN NEW CONSTRUCTION WITH 1/2-IN AND 3/8-IN AGGREGATES. THEIR PERFORMANCE WAS NOT AS GOOD IN THE CAPE SEAL METHOD AND WAS MUCH POORER IN SINGLE SAND SEALS AND IN PREMIX SURFACINGS CARRYING HEAVY TRAFFIC. IT SEEMS THAT TARS ONLY SHOW GOOD DURABILITY UNDER SOUTH AFRICAN CONDITIONS IN DENSE PREMIX SURFACINGS AT VERY HIGH BINDER CONTENTS. THIS SUGGESTS THAT THE USE OF TARS AND PREMIX SURFACINGS CARRYING HEAVY TRAFFIC IS PRECLUDED AS AT HIGH BINDER CONTENTS THE MIXTURES WOULD DEFORM AND BE UNSTABLE. THE BETTER PERFORMANCE OF THE MODIFIED TARS IN SINGLE SEALS CONTAINING SINGLE-SIZED AGGREGATES THAN IN SINGLE SAND SEALS, CRUSHER DUST PREMIX (CAPE SEAL METHOD) AND PREMIX SURFACINGS SUGGESTS THAT THEY PERFORM BETTER IN A THICKER FILM. THEIR LOWER PERFORMANCE IN PREMIX ALSO SUGGESTS THAT THEY ARE SUSCEPTIBLE TO THE GREATER DEGREE OF HARDENING WHICH TAKES PLACE DURING THE MIXING PROCESS. IT IS CONCLUDED THAT THE DIFFERENT PERFORMANCE OF TARS AND MODIFIED TARS IN DIFFERENT TYPES OF CONSTRUCTION INDICATES THE NEED FOR THOROUGHLY TESTING BINDERS IN THE DIFFERENT METHODS OF USE BEFORE DRAWING CONCLUSIONS ON THEIR PERFORMANCE.

  • Supplemental Notes:
    • Annual Rept 1965, SPECIAL REPT PAD 14, PP 12-13
  • Corporate Authors:

    Cncl Scient & Indus Res /S Africa

    /Nat Inst Road Res
    ,   USA 
  • Publication Date: 1966

Subject/Index Terms

Filing Info

  • Accession Number: 00210730
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 28 1970 12:00AM