LWD compaction control

We carry out compaction and bearing-stiffness control of earthworks and unbound pavement layers with a Zorn ZFG 3.1 light weight deflectometer fitted with a 10 kg drop weight. Each test point gives the dynamic deformation modulus, Evd, on site in about two minutes, so decisions can be made before the next layer is placed. As an independent third party, we carry out and report the tests impartially.

What we do

  • Subgrade, fill, subbase and base layers for roads, building platforms and other earthworks
  • Dynamic deformation modulus (Evd) from a set of three drops at each test point
  • Test points typically every 20–50 m along road alignments, or on a grid agreed for the project
  • Quick checks during rolling to guide the contractor’s compaction effort
  • Retesting of areas that fail the specified criterion after re-compaction

Standards

  • ASTM E2835-21(2026)

Why it matters

Evd reflects the stiffness of the compacted layer under dynamic loading, which is directly linked to how the layer will carry traffic and support the layers above it. Because a result is available within minutes, LWD testing allows dense coverage along a road without holding up the works. The method does not measure density, so where a specification sets density limits we combine it with sand cone tests. Because testing can be done on the day a layer is compacted, non-conforming areas can be re-compacted and retested before the next layer goes down.

What you receive

  • Test report to ASTM E2835 with the Evd value for each test point
  • Test points identified by chainage, layer and location
  • Comparison with the project acceptance value, where specified
  • Summary table showing the distribution of test points along the alignment
  • Retest results for re-compacted areas
  • Photographs of test locations where relevant

Ask us for a quote for LWD compaction control; our team is on site on weekdays and weekends to match your programme.

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