The kit itself is straightforward: a double-cone valve, a one-gallon threaded jar filled with dry, uniformly graded sand, and a base plate with a six-inch hole. On a Newcastle site—say, a brownfield plot near the Ouseburn Valley where the ground rises and falls in tight terraces—setting the plate level on compacted sandstone fill takes longer than the actual test. The sand cone method is still the benchmark for verifying field density on earthworks and pavement subgrade, especially where nuclear gauges are impractical due to licensing or site constraints. We run it to BS 1377-9 and the compaction spec in the 600 Series of the Manual of Contract Documents for Highway Works. Before starting the test, we always cross-check the maximum dry density from a lab Proctor test performed on the same material taken from the lift being tested.
A sand cone test measures the one thing that matters after every roller pass: the actual in-place density of the compacted soil.
Scope of work in Newcastle
Critical ground factors in Newcastle
Much of central Newcastle sits on glacial till overlying Coal Measures sandstone and mudstone, with pockets of soft alluvium along the Team and Tyne corridors. The till is dense in its natural state, but once excavated and recompacted it can be surprisingly sensitive to moisture content—a 2% swing above optimum can drop the dry density below the 95% line. We have seen this repeatedly on brownfield sites where contractors reuse site-won fill without adequate moisture conditioning. The bigger risk, though, is the presence of made ground: old mine workings backfilled with colliery spoil, ash, and brick rubble. These materials often have variable particle strength, and a sand cone test that passes on density can still mask a fill that will collapse under saturation. That is why we always pair field density with a particle density check and a moisture content from the same hole.
Our services
Our field density work in Newcastle covers three main areas, each tailored to the ground conditions we encounter from Gosforth to the Quayside.
Earthworks Compaction Verification
Sand cone testing on structural fill lifts for commercial and residential platforms. We work to the project's Method Compaction Specification, typically targeting 95% relative compaction on cohesive and granular fill, with full reporting that includes moisture content and air voids ratio.
Road Subgrade and Capping Acceptance
Testing to SHW Clause 612 and 613 on subgrade and capping layers before pavement construction. We measure in-situ density at the specified grid spacing and provide immediate pass/fail results so the contractor can proceed with the next lift without delay.
Utility Trench Backfill Compliance
Narrow trench conditions demand a smaller base plate and careful excavation. We test backfill in gas, water, and electric trenches across Newcastle's network of Victorian-era streets, where achieving specified density around buried services is critical to prevent future settlement.
Q&A
How much does a sand cone density test cost in Newcastle?
For a standard sand cone test on one lift, including the laboratory determination of the sand's bulk density and a moisture content from the same hole, you are typically looking at £70 to £100 per test. The exact figure depends on how many tests are done in one visit and the travel distance to the site. We can provide a fixed day-rate if the project needs multiple tests across a large area.
Which British Standard covers the sand cone method?
The sand replacement method for determining in-situ density is covered by BS 1377-9:1990. For the compaction specification and acceptance criteria, the project will usually reference BS 1377-4 for the Proctor curve and either the SHW Series 600 for highways work or a site-specific earthworks specification.
What size of test hole do you use in Newcastle's glacial till?
We normally cut a 200 mm diameter hole in glacial till because the material often contains cobbles up to 75 mm. Using a smaller 150 mm hole can give unrepresentative results when larger particles are excluded from the excavated material, so we size up to keep the mass of soil tested above the minimum specified in BS 1377-9.
How many sand cone tests does the specification require for earthworks?
For general earthworks, the SHW Clause 612 calls for one in-situ density test per 500 m² of each compacted lift. If the material is variable—as it often is on brownfield sites in Newcastle—the supervising engineer may tighten that to one test per 250 m². We always check the project-specific spec because it overrides the default frequency.
Can you use the sand cone method on Type 1 subbase?
Yes, but with a larger-diameter hole and careful hand excavation to avoid disturbing the compacted matrix. On Type 1 granular subbase we use a 200 mm plate and a calibrated sand that is fine enough to fill the surface voids without penetrating the material. The result gives a direct measure of the compacted density that you can compare against the vibrated density from the lab.