- Trenches in roads shall be backfilled and compacted in layers of thickness commensurate with the compaction equipment to a density of at least 95% of the maximum dry density. Field compaction shall be tested as follows:
- For cohesive soils - New Zealand standard compaction test, nuclear densometer and shear vane.
- For non-cohesive soils - New Zealand standard compaction test, nuclear densometer or dynamic cone penetrometer (Scala Penetrometer).
Testing by other means shall be subject to the approval of the Engineer.
- Trenches not in roads or paved areas shall be backfilled and well compacted with mechanical equipment in layers not exceeding 300mm thick.
- The Contractor shall undertake sufficient tests to demonstrate that the specified compaction standards have been achieved throughout.
- Compaction testing of fill material shall be in accordance with NZS 4402 Methods of Testing Soils for Civil Engineering Purposes.
- Compaction testing of subbase and base course shall be in accordance with IT-4 Transportation Network of the IDC.
Definitions in this section