FROM TAMPING BEAM TO SLIP-FORM

This public works special feature traces the development of concrete road construction from the start of concrete paving in the 1890's up to the present day. In the early period the concrete is described as being mixed - usually at the paving site itself - and dumped on the road formation, to be spread and levelled by shovel, rake and strike-off board; side forms were almost always timber pegged to the sub-base, and timber tamping beams spanning the forms compacted the concrete. Contracts involving the use of such techniques are described, and reference is made to the introduction of mechanical mixing plant and the box-hopper spreader. The importance of compaction is discussed and reference made to the vibrolithic process used as early as 1913 in the USA, the German Dingler Compactor used by the Surrey CC in the early 1930's which used a system of falling weights and surface-vibration compactors. The development of the slip-form paver in the 1950's is described by reference to rural road construction in the USA, leading to the introduction of two basic types. The first, described as a CMI paver employs a screw spreader distributing concrete already placed on the sub-base, usually by a separate spreader placer; compaction by a combination of immersed poker and surface vibrators; and finishing by a pair of oscillating beams and a float pan. The second, and more radical type of slip-form, of which the best example is considered to be the guntert and zimmerman paver, is the conforming-plate machine. This is described as essentially an extrusion machine in which the concrete, fed to the front of the paver by conveyor or deposited in advance on the sub-base, is fluidised by immersion vibrators and extruded between travelling forms with a top conforming plate to produce the slab. /TRRL/

Media Info

  • Features: Photos;
  • Pagination: p. 88
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00193950
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jun 13 1979 12:00AM