Soil Stabilisation Case Study: Lime Modification of Haul Roads at Magna Park, Lutterworth
Wet ground stopping your programme? This is what lime modification does about it.
Every earthworks contractor knows the problem. The ground is wet, it is moisture-sensitive, and the moment plant starts moving across it the haul roads go to pieces. Progress slows, machines struggle, and the usual answer is to dig it out, cart it away and bring stone in to replace it.
That answer works. It is also slow and expensive, and it puts lorries on the road that nobody wanted or budgeted for.
There is another way of dealing with it, and this is a recent example of it in practice.
The project
Ashclough Contractors were engaged by Holland Earthworks to improve wet, moisture-sensitive ground conditions and strengthen the site access haul roads at Magna Park, Lutterworth — one of the largest logistics parks in the country, and a site where plant movements do not stop for anybody.
The programme ran for 10 weeks.
The existing ground was a sandy clay. Rather than excavate and replace it, we treated it where it lay.
[Image: lime-stabilised-haul-road-magna-park.jpg — caption: Treated haul road at Magna Park, the strengthened running surface across the active works.]
What we did
The treatment was 2% lime modification, roughly 11 kg per square metre, worked to a depth of 300 mm.
In plain terms, the process runs like this:
- Spreading — lime is spread across the treatment area at a controlled, measured rate. Not by eye, and not approximately.
- Mixing — a rotavator works the lime through the full 300 mm depth so the material is treated consistently rather than just on the surface.
- Grading — the treated material is graded to the required level and profile.
- Compaction — the platform is compacted to lock in the strength.
The lime reacts with the clay and changes how the material behaves. It brings the moisture content down, breaks up the plasticity, and turns ground that was unworkable into a platform that carries plant.
The result
Testing on the completed lime-stabilised material returned a verified CBR of 31%.
For anyone not dealing in CBR figures day to day, that is a substantial result from ground that was previously wet and moisture-sensitive. It gave the site a consistent running surface for plant movements and made material distribution across the active works far more predictable.
The haul roads stopped being the thing holding the job up.
Why it was the right call commercially
The part that matters to whoever is paying for the job is this: the site-won material stayed on site.
That removed, at a stroke:
- The excavation of unsuitable material
- The muck away and disposal costs that go with it
- The imported stone or replacement fill needed to make good
- The lorry movements involved in both directions
On a site the size of Magna Park those are not small numbers. Every load that does not have to leave and every load that does not have to come in is time and money saved, and it is one less wagon on the local road network.
Key benefits on this project
- Improved ground strength and constructability
- Reduced excavation, disposal and imported replacement material
- Greater resilience for the earthworks programme through the wet
- More dependable site access and plant movements
- Verified CBR of 31% on completion
When is soil stabilisation worth considering?
It is worth a conversation if any of the following sound familiar:
- Haul roads breaking up under plant traffic
- Wet or moisture-sensitive clay holding up the earthworks programme
- A muck away and import bill that has grown beyond what was allowed for
- Working platforms needed for piling rigs or cranes
- Capping layers, sub-formations or car park and yard formations
- A site where the ground was always going to be marginal and the weather has made the decision for you
Lime is not the answer to every ground condition, and cement or a combination binder is sometimes the better fit. The starting point is always the material itself — what it is, how it behaves and what it needs to carry.
Talk to us about your site
Ashclough Contractors carry out soil stabilisation, lime and cement modification, earthworks, operated plant hire and tanker services for contractors and developers across the UK.
If you have got ground that is not doing what you need it to, send us the details — location, the material you are dealing with, the depth and area involved, and what you need it to carry. We will tell you straight whether stabilisation is the right approach.
Call: 01204 913715
Email: info@ashcloughcontractors.co.uk
