CONCRETE FINISHES FOR HIGHWAY STRUCTURE

THREE BROAD GROUPS OF FINISHES ARE DEALT WITH AND THE MATERIALS AND PROCESSES FOR PRODUCING THESE FINISHES ARE DESCRIBED AND EXPLAINED. IT HAS BEEN POSSIBLE TO INCLUDE IN A BOOKLET OF THIS NATURE ONLY A SMALL SELECTION OF SUCCESSFUL FINISHES, BUT THEIR VARIETY IS SELF-EVIDENT. THE EXAMPLES WHICH HAVE BEEN ILLUSTRATED ENDEAVOR TO SHOW THE WIDE VARIATIONS IN COLOR WHICH SOME ENGINEERS HAVE ACHIEVED. IT IS HOPED THAT THEY WILL ALSO HAVE MADE POSSIBLE SOME APPRECIATION OF THE VARIETY OF TEXTURES AVAILABLE. EACH OF THE THREE BASIC TECHNIQUES WHICH HAVE BEEN MENTIONED PRODUCES ITS OWN CHARACTERISTIC FINISH. BUSH-HAMMERING WILL REMOVE THE OUTER SKIN OF LAITANCE OF THE CONCRETE AND WILL ATTACK BOTH THE AGGREGATE AND THE MATRIX WITH A CHIPPING ACTION. THE RESULT IS A VISUALLY MATT FINISH WHICH HAS AN OVERALL APPEARANCE OF REGULARITY. THE CHOICE OF SPECIAL AGGREGATES CAN PRODUCE MANY SUBTLE VARIATIONS OF COLOR AND QUALITY OF REFLECTED LIGHT. GRIT-BLASTING ETCHES BOTH AGGREGATE AND MATRIX, PRODUCING A SOFTER EFFECT THAN THAT OF BUSH-HAMMERING. PROLONGED APPLICATION PENETRATES MORE DEEPLY INTO THE SOFTER MATRIX, GIVING THE AGGREGATE PARTICLES MORE PROMINENCE, WHICH IS PARTICULARLY EFFECTIVE WHEN A GAP-GRADED CONCRETE MIX IS USED. GREAT VARIATIONS OF PATTERN AND PENETRATION ARE POSSIBLE WITH POINT-TOOLING. BRUTAL BUT EFFECTIVE, THIS TECHNIQUE HAS BEEN RESPONSIBLE FOR SOME EXCELLENT FINISHES. IT IS NECESSARY WITH ALL EXPOSING TECHNIQUES TO REMEMBER THAT THE SPECIFIED CONCRETE COVER SHOULD ALLOW FOR THE MATERIAL WHICH WILL BE REMOVED, BUT THE POINT-TOOL, WHICH PENETRATES DEEPLY, SHATTERING AGGREGATE PARTICLES AND MATRIX ALIKE, MAKES IT ESSENTIAL TO SPECIFY BOTH THE REQUIRED COVER AND THE MAXIMUM PERMISSIBLE PENETRATION. HAVING TAKEN THIS PRECAUTION, THERE NEED BE NO FURTHER ANXIETY OVER THE DURABILITY OF THE FINISH.

  • Corporate Authors:

    Cement and Concrete Association

    52 Grosvenor Gardens
    London SW1W 0AQ,   England 
  • Authors:
    • Tiller, R M
    • Ward, F W
  • Publication Date: 1972

Media Info

  • Features: Photos;
  • Pagination: 27 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00209965
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 29 2004 5:00PM