Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?
--
Tim Lamb

Tim Lamb Wrote in message:
Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?

Presumably no one could prove it wasn't 40+ years ago?

--
Jim K


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"Tim Lamb" wrote in message
...

Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6" of
mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?

I've heard the same rumours - 'it degrades the concrete' - well if it does I
have many examples here of concrete laying over planings ! Most have a
membrane between but not all. How many roads have a concrete sub base with
tarmac on top - very many including the M20. Not sure how it is supposed to
degrade the concrete, after all the asphalt content is waterproof as is the
contained agregate.

Andrew

On Sunday, 17 April 2016 10:54:50 UTC+1, Tim Lamb wrote:
Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?
--
Tim Lamb

I have often used planings.
Never heard of any such problems.

The main thing was the occasional big lumps that had to be smashed with a sledge hammer.

On 17/04/2016 10:54, Tim Lamb wrote:
Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?

Its generally not recommended as a sub base because the particle sizes
are not well controlled. So you can end up with sizeable voids in it
next to large lumps, that will then allow fines to migrate into them
over time. Obviously of its been down 20 years then this is going to be
far less of a problem its probably consolidated properly and is unlikely
to move further.

--
Cheers,

John.

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In message , John
Rumm writes
On 17/04/2016 10:54, Tim Lamb wrote:
Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?

Its generally not recommended as a sub base because the particle sizes
are not well controlled. So you can end up with sizeable voids in it
next to large lumps, that will then allow fines to migrate into them
over time. Obviously of its been down 20 years then this is going to be
far less of a problem its probably consolidated properly and is
unlikely to move further.

OK. It has had 20 years of grain storage, tractor movement, barn dances
etc. without visible cracking.

In view of the current Permitted Development Rights I wondered if any of
the tar constituents have been declared carcinogenic or lead to the
concrete deteriorating in some motorway bridge fashion.

Local planning will use any excuse to refuse domestic conversions.


--
Tim Lamb

On 4/18/2016 8:45 AM, Tim Lamb wrote:
In message , John
Rumm writes
On 17/04/2016 10:54, Tim Lamb wrote:
Is anyone aware of possible issues? Thread elsewhere.

I have some, put down 20 years ago. Compacted, covered with dpm and 6"
of mesh reinforced concrete.

Odour? Chemical reaction? EU waste directive? or...?

Its generally not recommended as a sub base because the particle sizes
are not well controlled. So you can end up with sizeable voids in it
next to large lumps, that will then allow fines to migrate into them
over time. Obviously of its been down 20 years then this is going to
be far less of a problem its probably consolidated properly and is
unlikely to move further.

OK. It has had 20 years of grain storage, tractor movement, barn dances
etc. without visible cracking.

In view of the current Permitted Development Rights I wondered if any of
the tar constituents have been declared carcinogenic or lead to the
concrete deteriorating in some motorway bridge fashion.

I'd be very surprised if bitumen based materials directly cause concrete
to deteriorate. I think the motorway bridge problem is probably
corrosion of rebar because of construction errors and/or concrete
cracking. I suppose that incorrect surfacing might lead to blocking of
drainage channels and water pooling sub-surface leading to rebar corrosion.

Obviously, who knows if some day anything containing tar will be deemed
carcinogenic, but I think the general argument is that old tarmac has
lost its volatiles, and also any residual "nasties" are pretty well
trapped physically, rather like the asbestos fibres in asbestos cement.