Certificated and Non certificated crushed concrete???

[TheOriginalTableLeg]

Can anybody please tell me what the difference is between the certificated and non certificated crushed concrete?

I need some for a gravel driveway I am doing on my home, and the MOT type 1 certificated stuff is £38 per ton plus vat, where as the non certificated stuff is only £11 per ton plus vat.

I am only graveling a driveway.

Appreciate any info.

 

[RedHerring2]

Purely a guess, but the certificated is exactly what it says on the tin whereas the non-cert'd can have all sorts of foreign bodies in it.
(That's in it not innit)

(I hope this doesn't start an anti-immigration sub-thread)

 

[TheOriginalTableLeg]

Thanks for the reply.

I understand what you are saying, but does that mean it is no good for a sub base?

 

[RedHerring2]

I'm only a DIY'er but I wouldn't use the non-cert'd stuff for a sub-base 'cos there's a chance it'll have bio-degradeable stuff in, which will do just that and over time you'll end up with voids under the surface.

Another guess is that a Building Inspector would not pass it either.

But it's just my guesswork. I've never used it so I have no experience of how much 'contamination' there would be.

Incidentally, I think that MOT type 2 is OK and a bit cheaper than MOT type 1.
See this:
//www.diynot.com/forums/viewtopic.php?t=127643

If the non cert'd stuff is type 2, then it's probably OK to use, but the price would make me very wary.

 

[TheOriginalTableLeg]

I have 2x companies local to me offering the following:

company 1-
Type 1 crushed concrete £15 per ton +Vat

Company 2-
Non certificated crushed concrete £11 per ton +Vat
75mm to dust.

Aside from the fact that company 2 has 75mm (quite big for my driveway?) to dust, any reason why one is any better than the other? (aside from the price)

???

 

[RedHerring2]

How come there's a £23 discrepancy from your first post to your most recent?

Perhaps this explains it better:

http://aggregain.wrap.org.uk/terminology/type_1.html

Reproduced:

Type 1


A specification for granular materials used as sub-base, as defined by the Specification for Highway Works, clause 803. Type 1 materials include crushed rock, crushed slag, crushed concrete and well-burnt, non-plastic shale - but sand and gravels are excluded.




Type 2


A specification for granular material used as sub-base, as defined by the Specification for Highway Works clause 804. Type 2 materials include crushed rock, crushed slag, crushed concrete, well-burnt non-plastic shale, and natural sand and gravels.



I think I've seen somewhere that Type 1 is more or less guarranteed to have no voids with 40mm particles down to dust, Type 2 probably no voids with 70mm particles down to dust and Type 3 up to 30% voids are possible.

I would ask your suppliers if they state that their product is MOT Type 1/2.

I think I've also misread your intentions. Are you thinking of using this as the finished surface? If so, I would think again. It should be used as a sub layer, compacted, and in the case of gravel as a finished surface, separated with a permeable material.

But I would repeat, I'm no expert. It's just my opinion.

 

[TheOriginalTableLeg]

How come there's a £23 discrepancy from your first post to your most recent?

Not a discrepancy, the figures in the first post are from the same company (company 2).

 

[TheOriginalTableLeg]

Thanks for the reply. This is purely intended as a 6" compacted sub base for a 2" gravel top.

 

[noseall]

Wisdom suggests that if you are laying any concrete then steer away from 'contaminated' products, particularly if using within a dwelling.

Problems can arise when using infill that has the potential to release harmful gasses. Sulphate gas can destroy cement based products particularly in damp conditions.

MOT type 1 is an inert and stable hard core infill that is suitable for most applications.

I am only graveling a driveway

Use crushed concrete or whatever. I don't think it will make a difference.
I would be a little nervous though if there was a lot of broken tarmac within the infill!

 

[geraint]

Wisdom suggests that if you are laying any concrete then steer away from 'contaminated' products, particularly if using within a dwelling.

Problems can arise when using infill that has the potential to release harmful gasses. Sulphate gas can destroy cement based products particularly in damp conditions.

MOT type 1 is an inert and stable hard core infill that is suitable for most applications.

I am only graveling a driveway

Use crushed concrete or whatever. I don't think it will make a difference.
I would be a little nervous though if there was a lot of broken tarmac within the infill!

i am concerned about the difference between what you are all talking about.. type 1 is a natural sub base... i.e. stone. crushed concrete does have no compatibility with type 1. or with the lesser aggregates.