CBR testing in Manchester.

Same-day and next-day dates are often available, subject to the schedule. Manchester is a long run from our laboratory in Milton Keynes, so a same-day visit depends on where the team already is, and a next-day booking is the more realistic ask. Give us the postcode, the number of positions and the test type on 0161 871 7372 and we will offer the earliest date we have.

Because boulder clay is moisture sensitive and this is one of the wettest parts of England. CBR is strongly influenced by moisture content. A till formation tested straight after trimming can return several times the value it gives after two days of rain and a few dumper passes. The result is true for the day it was taken, so test when the formation is in the condition the road will be built on.

At natural moisture content and freshly trimmed, glacial till often gives a usable in-situ CBR. Wet and remoulded, the same material commonly falls to low single figures, and soaked laboratory values are usually lower than dry-day site values. There is no universal pass mark. A low number tells your designer how much capping and sub-base to allow, and it is better known before the stone is ordered than after.

We can, but it is rarely worth doing. On peat and soft alluvium the CBR is so low that the design will not rely on it. Roads and platforms over the mosses are built on a designed thickness of fill, usually over a geogrid, and the tests that matter are plate bearing and density on that fill. Tell us what the designer has asked for and we will match the testing to it.

Send us the clause. For adoptable estate roads it is normally an in-situ CBR at formation level, often backed by a soaked laboratory CBR for design. For yards on capping or recycled fill it is more often plate bearing with a derived CBR. In-situ, laboratory and derived CBR are different measurements, and the report should say which one the number came from.

Only where the material suits the method. The plunger is intended for material up to about 20 mm, so ash, sand and fine fill can be tested, but demolition rubble, brick and dock fill cannot be tested reliably. Results on made ground also vary sharply between positions. Expect to need more positions, and expect us to suggest plate bearing where the fill is coarse.

The specification or the adopting highway authority sets the number. Where they are silent it depends on the length of road and the variability of the ground. Positions are spread along the formation so soft areas show up, and each test is made at the level the design relates to. In-situ testing is commonly carried out in accordance with BS 1377-9. Send the layout and we will suggest a number for the quote.

Yes. We take a bulk disturbed sample at formation level while we are on site and it goes back to the laboratory with the technician, or you can courier one to Milton Keynes. The specimen is remoulded into a 152 mm mould at the specified compaction and moisture condition, soaked where required, and tested under surcharge discs, commonly to BS 1377-2. Confirm the sample size with us before sampling.

On Manchester till it is usually worth it, and many local specifications require it. A CBR value on its own does not tell the engineer whether the formation was tested dry, wet or somewhere between. A moisture content on a sample from the test position lets the result be read against the material’s natural and optimum moisture contents, and explains why two positions on the same clay gave different numbers.

The test level exposed and trimmed flat, safe vehicle access to each position and a clear working area. The equipment is vehicle mounted and reacts against the weight of the vehicle, so very soft ground and steep gradients can rule a position out. Have the formation ready when we arrive, because it is a long trip to repeat. The plunger hole is backfilled before we leave.

Hixtra holds UKAS accreditation to ISO/IEC 17025 under schedule number 8996. Accreditation is granted method by method, not to the company as a whole, so it applies only to the tests listed on our current schedule. Most of our soil tests are accredited. If your specification or the adopting authority requires an accredited result, name the CBR method when you enquire and we will confirm whether it is on the schedule, and whether the report will carry the UKAS mark, before you book.

Every visit is quoted from the site postcode, and because Manchester is a long run, travel is a real part of the price. The way to keep the cost per test down is to group everything into one visit: all the CBR positions, any plate tests and any sampling on the same day. Standby time, restricted access and out-of-hours working add to it. Send the postcode, positions and dates and we will quote.

No. Hixtra has no office, depot, staff or vehicles in Manchester or anywhere else in the North West. Every team travels from the laboratory in Milton Keynes, and the 0161 number rings through to the same people as our other numbers. Coverage means we will come to you, not that we are based locally, which is why a firm ready date and grouped positions matter.