IMPROVEMENT OF THE POLISHED STONE VALUE OF SLAG ROADSTONE BY HEAT TREATMENT

THE AUTHORS DESCRIBE STUDIES CARRIED OUT TO IDENTIFY THE MINERALOGICAL CRYSTALLOGRAPHIC AND PHYSICAL PROPERTIES WHICH INFLUENCE THE PSV OF BLAST FURNACE SLAG ROADSTONE WITH A VIEW TO IMPROVING THE PSV OF SLAG WITHOUT CAUSING DETERIORATION IN WEAR RESISTANCE. IT WAS FOUND THAT THE COMPOUNDS PRESENT IN THE SLAG HAVE DIFFERING PSV, AND THAT PSV OF SLAG DEPENDS PREDOMINANTLY ON CRYSTALLINE TEXTURE AND POROSITY. IT WAS ESTABLISHED THAT BOTH INCREASED CRYSTAL SIZE AND INCREASED POROSITY IMPROVE THE PSV OF BLAST FURNACE SLAG BUT LARGE POROSITY DEGRADED THE WEARING PROPERTIES OF THE AGGREGATE AND WOULD HAVE RESULTED IN A SHORTENED USEFUL LIFE AS A ROADSTONE. INCREASING THE SIZE OF THE CRYSTALS IN BLAST FURNACE SLAG PROVED TO BE A PRACTICABLE WAY OF IMPROVING ITS PSV. THIS DESIRED CHANGE IN CRYSTAL DIMENSIONS WAS ACHIEVED BY PLANNED HEAT TREATMENTS. THE HEAT TREATMENT PRODUCED SOME CHANGES IN THE CHEMICAL PHASE ASSEMBLAGE OF THE SLAGS AND THESE HAD A MINOR EFFECT ON PSV. WHERE THESE CHANGES WERE ACCOMPANIED BY AN INCREASE IN THE RANGE OF MICROHARDNESS THE PSV WAS ALSO INCREASED. THE BEST IMPROVEMENT IN THE PSV OF SLAGS WAS OF THE ORDER OF 10 UNITS. THE INFLUENCE OF CRYSTAL SIZE WAS FURTHER DEMONSTRATED BY ACHIEVING A 10 UNIT DECREASE IN THE PSV OF SLAGS BY MEANS OF A HEAT TREATMENT WHICH LED TO CRYSTALS MUCH SMALLER THAN THOSE PRESENT INITIALLY. A QUANTITY OF ONE SLAG HAS BEEN HEAT TREATED TO IMPROVE ITS PSV AND ROAD TESTED FOR SKID RESISTANCE WITH SATISFACTORY RESULTS.

  • Availability:
  • Corporate Authors:

    Whitehall Technical Press Limited

    Wrotham Place
    Wrotham, Sevenoaks, Kent ME14 1PE,   England 
  • Authors:
    • Gutt, W H
    • Hinkins, B
  • Publication Date: 1972-4

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 5-14
  • Serial:
    • Highway Engineer
    • Volume: 4
    • Issue Number: 4
    • Publisher: Whitehall Press Limited
    • ISSN: 0306-6452

Subject/Index Terms

Filing Info

  • Accession Number: 00217945
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: May 24 1974 12:00AM