Primary vs Recycled - MOT type 3 - subbase for PERMEABLE driveway

[bmj1]

Hi guys,

 

Preparing my driveway (resin bound gravel). Needs to be SUDs compliant.

 

Planning to do:

1. 150mm MOT type 3
2. 80mm open textured tarmac
3. 20mm resin bound gravel

 

Any comments on the above buildup ?

 

Any advice on if MOT type 3 needs to be Primary (e.g. limestone) or can be Recycled (e.g. concrete) ?

 

Many thanks in advance

Edited March 18 by bmj1

[nod]

Limestone is better drainage  But more expensive 

[Big Jimbo]

What it should be to be suds compliant is "No fines"on the base.

[Alan Ambrose]

I think it depends a lot where in the country you are and the local geology. Around here it appears v difficult to locate an ‘MOT 3’ material off-the-shelf. But then it’s all sand and clay here.

 

I think you (and I) want crushed granite, limestone or basalt with ‘no fines’.

[BadgerBodger]

Recycled aggregate comes in various qualities. The more premium products will be manufactured using WRAPS protocol. When I am siding it I’ll ususally get some samples delivered (20t) to see how it places and what’s in it. Usually it comes with quite a few contaminants like wood or plastic which aren’t desirable in road build-ups. If you can get some certainty is is just concrete with no fines you could be ok. 
 

If I were doing it i’d use type 1x or type 3. again the quality of the stone is important. You want MOT (frost resistant) as it will break down more slowly and the top 300mm or so is susceptible. 

My drive will be woven geotextile, geogrid, 200mm type 1x or type 3, geotextile, 40mm clean single size.

 

geotextile at the bottom helps ensure fines do not migrate upward

 

[BadgerBodger]

 

14 minutes ago, Alan Ambrose said:

I think it depends a lot where in the country you are and the local geology. Around here it appears v difficult to locate an ‘MOT 3’ material off-the-shelf. But then it’s all sand and clay here.

 

I think you (and I) want crushed granite, limestone or basalt with ‘no fines’.

Igneous for the win. But unless you’re in Scotland and some very specific areas in (the southwest if I recall correctly) it’s all imported from the nordics and comes with a price tag. 

 

 

 

[Big Jimbo]

2 minutes ago, BadgerBodger said:

40mm clean single size.

 

My Mrs says you can't walk in high heels on that.