Making access road - depth of base?

Recoil · Mar 7, 2016

Going to be making an access road into some fields. Will get the odd tractor or lorry using it but mainly just cars/4x4s. Planning to get a digger in to dig down for the base, lay teram on the soil and tip recycled stone/concrete on top of this and then eventually top with something a bit finer on the top to get a tidy finish. Question is what depth should the stone be? Ground is pretty dry but I can get the stone for a good price so don't mind putting it down thick as a precaution. Thanks.

RWG Contracts · Mar 7, 2016

I'd got a 1' to 18" @BAC??

Matt L · Mar 7, 2016

You want to remove all topsoil, down to approx. 300mm.
I would suggest using road planings as they don't tent to have bits of reinforcing in them.
Spend plenty of time rolling the crush and planings so it wont move about once it has been constructed and therefore need more material to level it off.

If you want to use it all year round, I would suggest installing a land drain under the centre of the road and stoning up to the formation ie 300mm below ground surface, this allows the road to be dry all year round and will lead to a lot less potholing throughout the winter months.

BAC · Mar 7, 2016

RWG Contracts said:
I'd got a 1' to 18" @BAC??

Depends what the ground is underneath to be honest. If it's solid then don't go stupid. 250 base with a 50mm blinding

Make sure the material has fines in it otherwise it won't bind, track it in layers. Wouldn't bother with a land drain as it will only block over time causing more issues and will collapse with compaction

The main reason for potholes is because people don't put a camber on the track which allows water to sit and washes material out with passing traffic

Matt L · Mar 7, 2016

Currently installing a centre road drain and would not advise if it was going to collapse under load. They are plenty strong enough installed at 900mm deep with stone to the formation level.

We have a farmer with two tracks across the same field. The one with the drain has never needed anything doing to it. The other one potholes and moves around despite being installed to same spec and camber both installed at the same time.

Recoil · Mar 7, 2016

I was trying to work out roughly how much stone I would need and working it out at 30cm deep, so not too far off. Would use more if ground is wet underneath, but will give me a rough idea of cost. Thanks.

BAC · Mar 7, 2016

Recoil said:
I was trying to work out roughly how much stone I would need and working it out at 30cm deep, so not too far off. Would use more if ground is wet underneath, but will give me a rough idea of cost. Thanks.

What size stone were you thinking?? Would either use hardcore or 75mm then top with 25mm or planings

BAC · Mar 7, 2016

Sandstone works well as a cover as well

Matt L · Mar 7, 2016

Depth x width x length all in meters multiplied by 1.8 for crush multiplied by 1.2 for wasteage and slight variations will give you the weight you will need.

So for example 100m track 3m wide would be...
0.3x3x100x1.8x1.2 is 194.4T

If you want two different layers then two different calculations for different materials

diggerjones · Mar 7, 2016

Wouldn't bother with a drain under the road. If I was putting a drain in, I would put it on the outside of track and canver the road to it. Leest you could get at it then.
From my limited experience , when stone,mot crushed hardcore planings etc, is layed down and compacted. Over time it seals the surface and you don't get much water going through it

Matt L · Mar 7, 2016

Agreed but it takes the water away from under the sealed surface.
Each to their own and agree there are different ways of doing th same job.

BAC · Mar 7, 2016

topless_matt said:
Agreed but it takes the water away from under the sealed surface.
Each to their own and agree there are different ways of doing th same job.

if the ground is stable underneath then no bother. if the ground is pure sh!t then I would agree

Hesston4860s · Mar 7, 2016

There's no terram under mine, I did about 6-8 inch of rubble tracked in and then 3-4 inch of 2 inch clean limestone tracked in.
It's been down about 2 year now and had a fair amount of traffic including hgv's, it stood it very well.

Andrew K · Mar 9, 2016

Preparation is the key, I would go down to around 12" as a minimum, put down Terram then apply around 8 to 10" of decent crushed concrete with a thin layer of fines to bind it in.
Roll it well, then finish it off with a thin layer of decent road planings and roll it again plenty on a hot day ideally. Top up with planings if required.

A cambered road is best to reduce potholing I agree.

tomlad · Mar 11, 2016

If rolling in the planing with a vib ride on roller we put black ' road emulation ' in the water tank dribbling on the drums
Helps the plainings go back to tarmac
The amount is a art form not to much makes it spongy .
Does help to set it

wibbsy · Feb 21, 2017

Hi, I'm looking at how to build a 400m field track. From my understanding, is this a good construction:
If not what is missing/wrong?

https://www.dropbox.com/sc/oimstj62gxap3ad/AADtmZbaoMisSJUcGYcJEcr_a

BAC · Feb 21, 2017

wibbsy said:
Hi, I'm looking at how to build a 400m field track. From my understanding, is this a good construction:
If not what is missing/wrong?

https://www.dropbox.com/sc/oimstj62gxap3ad/AADtmZbaoMisSJUcGYcJEcr_a

Are you just creating wheel tracks rather than a full width one??

gusbs5502 · Feb 21, 2017

For the unwary.... be careful when accepting road planings as you might be getting more than just planings! Make sure you know where they have come from and that they are amongst other things free from contamination such as hydrocarbons etc. The risk is yours if you choose to use them so check their provenance.

For those who have trouble sleeping or are looking at perhaps developing some land for housing here is a link to an old Kent County Council Guide which will can be quite informative, although technical in places there are some good diagrams and flow charts.

https://www.google.co.uk/search?q=r...efox-b-ab&gfe_rd=cr&ei=i3usWJDdE6yN8QeBzbnIAg

wibbsy · Feb 21, 2017

BAC said:
Are you just creating wheel tracks rather than a full width one??

As the length is 400m+ then I think trying to excavate and build a full road will be costly..thus yeah looking to see if I can just get away with 2 wheel tracks.

Paul E · Feb 21, 2017

Would probably be more costly to dig 2 wheelings out than a full width road, but then what do I know?
Irrespective of the cost, would that be worth all the faffing about for what would be little financial saving?
If you're on a budget I have always found it better to do a proper job in 2 halves (eg 200m + 200m) rather than doing it all to half spec.

Making access road - depth of base?

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