NEW M40 FACES REBUILD AS LIME BASE HEAVES

Large parts of the new M40 motorway may have to be rebuilt because the road surface has been lifted up to 150 mm by swelling sulphates in the lime stabilised sub-base. Cracks have appeared in the continuously reinforced concrete roadbase which damaged the bituminous surfacing. Slices have been sawn out of the 230 mm thick concrete to reveal that the expansive reaction is occurring 500 mm or more below the cement bound layer and granular sub-base and in the lime stabilised material under it. The use of quicklime to strengthen in situ soil was adopted as a less expensive option to using increasingly scarce granular fill. Investigations are in hand to attempt to determine the cause of the failure of 5 per cent of the area where the lime stabilisation capping layer has expanded. It is possible that it has been inadequately treated, but uneven mixing or incorrect amounts of water could also be responsible for the failure. It is likely that the complete M40 Oxford to Birmingham route will be opened on time in March 1991 and the affected 16 km long section could be subjected to roadworks when more of the damage appears. (TRRL)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • Robbins, J
  • Publication Date: 1990-7-5

Language

  • English

Media Info

  • Pagination: p. 5-6
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00617423
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 30 1991 12:00AM