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Base reinstatement (NG6.3)

CBGM base in flexible and composite roads

CBGM base has a slump of zero and can be suitable for immediate overlay depending on the aggregate grading and interlock before any significant strength gain during curing. The relatively low cement-water ratio also means this type of material has low potential for shrinkage during curing. Conversely, concrete and wet lean concrete typically require strength gain to enable overlay without damaging the surface.

Overlaid modular layers

  1. This Code permits the re-use of cobbles and setts for the reinstatement of the relevant layer. However, it is often extremely difficult to achieve a performance from reinstatements similar to that of the original, i.e. a well interlocked and ‘stress hardened’ layer. Failure to achieve this structural stiffness could result in failure of the reinstatement and particularly any surfacing materials laid thereon.
  2. The Code does not permit the re-use of penning, in which modules are laid upright in an interlocking manner, thus exhibiting greater stiffness than an equivalent layer of cobbles or setts would.