CONCRETE ROAD BREAKTHROUGH: MCGREGOR SLIPS FULLY DOWELLED SLAB IN ESSEX

ON A CLEAR PREPARED SUB-BASE, THE ROBERT MCGREGOR SLIPFORM ROAD PAVER CAN NOW LAY A PLAIN CONCRETE SLAB UP TO 13M WIDE IN ONE OPERATION, LEAVING THE FORMATION IN FRONT OF THE MACHINE FREE FOR LORRIES TO DISCHARGE CONCRETE STRAIGHT INTO THE FRONT HOPPER. ALL THE TRANSVERSE CONTRACTION JOINT DOWELS AND THE LONGITUDINAL JOINT TIE BARS ARE AUTOMATICALLY INSERTED BY THE MACHINE AS THE SLAB IS SLIPFORMED. THE REMAINING OPERATIONS ARE TO INSERT THE TRANSVERSE JOINT SEALER-AN EVACUATED NEOPRENE STRIP-AND TO BRUSH THE TEXTURE DEPTH AND SPRAY THE CURING COMPOUND; THESE REQUIRE TWO EXTRA TRACKED MACHINES. THE EQUIPMENT HAS BEEN USED IN RECENT WEEKS ON THE MARGARETTING BY-PASS, A SHORT TWIN THREE LANE CONTRACT ON THE A12 DESIGNED BY THE ESSEX SUB-UNIT OF THE EASTERN ROAD CONSTRUCTION UNIT. IN THIS CONTRACT, A PLASTIC STRIP WAS SUCCESSFULLY USED AS AN AGGREGATE SEPARATOR. THE STRIPS ARE TOWED ON STEEL KEELS UNDER THE PAVER AND UNDER THE JOINT SEAL INSERTER THROUGH THE GREEN CONCRETE WHILE IT IS STILL BEING VIBRATED. POLYTHENE UNDERLAY ROLLS WERE FITTED IN FRONT OF THE HOPPER SO THAT THE SHEETS ARE UNROLLED DIRECTLY UNDER THE PAVER AS IT MOVES. /TRRL/

  • Corporate Authors:

    New Civil Engineer /UK

    ,    
  • Publication Date: 1972-10-12

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 20
  • Serial:
    • Volume: 11

Subject/Index Terms

Filing Info

  • Accession Number: 00215763
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: Jul 16 1974 12:00AM