HarDcore advice

[wobbilyhead]

Hi I'm laying a driveway of slabs and block paving and was going to lay hardcore and wacker it in then lay a concrete screed to lay the slabs on, problem I'm having is which hardcore! I rang my local quarry and asked for scalpings but got offered 1,2 or 3 inch to dust and 1,2 or 3 inch clean.

Now I'm not sure first what the difference is or which would be best for a double driveway.

Can anyone please advice me?

Thanks in advance.

 

[EddieM]

DTp type 1 usually called MOT type 1

Quick guide

Excavate to good a sub grade. depth dependent on soil conditions, intended use of drive

100 - 150 mm layer of crushed contrete. Compact.
150mm layer of DTp Type 1 Compact.
30mm layer soft sand compact
Permeable membrane.
25mm layer soft sand, compact.
5 mm layer soft sand not compacted.
60mm thick blocks (better than standards 50mm blocks. Compact (rubber plate on compactor). Then brush in dry 2:1 (stiffish) sand and mortar. Sprinkle lightly with hose. Leave a week.

That's the material list, much more on how to do it here

 

[wobbilyhead]

Thanks but which of the types of hardcore offered would be DTp1

 

[EddieM]

Thanks but which of the types of hardcore offered would be DTp1

Don't really understand the question DTp1 is DTp1 it is a bound hardcore. i.e. mix of ballast and clay. Scaplings are really just stone chips and to my knowledge not bound.

 

[wobbilyhead]

Sorry, when I rang the quarry and asked for hardcore I was offered 1,2 or 3 inch to dust and 1,2 or 3 inch clean, I'm not sure which would be suitable for the drive.

 

[EddieM]

My advice is neither, go for DTp 1 or MOT type 1 which ever name you prefer.

 

[hotrod]

I rang my local quarry and asked for scalpings but got offered 1,2 or 3 inch to dust and 1,2 or 3 inch clean.

Hi wobs. As eddie says, MOT is also known as DTp1. Around these parts it is also known as 40mm down (to dust), so if the quarry send you 2" to dust you will be on the right track. That said, if you ask them for MOT they should know what to send you.

 

[noseall]

30 or 40mm to dust will be great for a drive.

If a quarry does not know what mot type 1 is then God help us!.

 

[theoldun]

Wobbly, let me answer your question.
DTP/1 and MOT/1 are exactly the same material DTP is Department of Transport, and MOT is Ministry of Transport.. Both are specification names for highway work.
Neither consist of hardcore, ballast or clay. Both consist of either crushed concrete, limestone, granite stone, grit stone or what ever a local quarry has as waste.
You want MOT/1 (40mm down to dust)
With all due respect, do not work to specification posted. It is completely wrong, especially the last part that will completely destroy the design for a flexible and permable paving.
old un. Guidance only.

 

[Thermo]

DTp type 1 usually called MOT type 1

Quick guide

Excavate to good a sub grade. depth dependent on soil conditions, intended use of drive

100 - 150 mm layer of crushed contrete. Compact.
150mm layer of DTp Type 1 Compact.
30mm layer soft sand compact
Permeable membrane.
25mm layer soft sand, compact.
5 mm layer soft sand not compacted.
60mm thick blocks (better than standards 50mm blocks. Compact (rubber plate on compactor). Then brush in dry 2:1 (stiffish) sand and mortar. Sprinkle lightly with hose. Leave a week.

That's the material list, much more on how to do it here

eddie, with all due respect thats going to end up with a sinking driveway with soft sand, you dont need the permeable layer (and if you need one it doesnt go there!) and you use kiln dried in the joints not a dry mortar mix.

 

[theoldun]

Thermo, Nice to see that their are knowledgable posters on this forum. We have only started posting here, and some of the answers I have read have made me cringe.
I have only started posting. due to the fact, that in my 58 years in the industry. so many kind people have shared their knowledge with me, and dispite the fact that I still run a few lads and build a couple of houses a year, I have a little time on my hands now, and I feel it is my duty to pass on my knowledge to any one who cares to listen. Feel better now that I have go that of my chest.
old un,

 

[EddieM]

Fair enough I copied it from somewhere, but will bow to much more experienced advice of course. So OP ignore the advice about laying the drive (although it's not that different to the advice given in www.pavingexpert.com but I'm certainly not going to argue with people who do this stuff for a living !!) , but what you're after is DTp1 or MOT type 1.