Use MOT as ballast for concrete ?
sm_jamieson
of MOT (crushed limestone I guess).
I only need about 0.1 m^3 of concrete.
Can I use the MOT as ballast, instead of going to B&Q and grabbing
bags of gravel and sand etc ?
Thanks,
Simon.
JimK
you'll still need sand but I expect yes go for it (unless mission
critical but that quantity and mix ratio I doubt it will be a prob)
what's going to be doing?
cheers
JimK
sm_jamieson
It is some lumps of concrete to buttress an internal loadbearing wall
whose foundation I have to dig down next to in one place for a toilet
connection. It will be sitting mostly under the ground.
Simon.
JimK
ah yes - I remember now!
Yeah go for it - get some sand in there though, maybe 1:1:5? see how
it feels on mixing up
(there won't be enough fines in the MOT as it digs at least)
Cheers
JimK
dennis@home
"sm_jamieson" <sm_ja...@hotmail.com> wrote in message
news:c060b94a-8427-4015...@g10g2000yqh.googlegroups.com...
I would not use it without checking with an expert first.
Concrete ballast is graded to leave gaps for the sand and cement to fill,
MOT may be graded to not have the voids (MOT type 2 has no voids IIRC, MOT
type 3 has 30% voids IIRC).
> Simon.
The Natural Philosopher
Umm. Its got two not very nice properties.
Its bloody WEAK and it sucks up moisture.
If you just want bulk with a smooth surfcee, add extra waterr, and OK.
IF its go to take serious loads, be bloody careful.
NT
I understand its sometimes used cement stabilised to form road
surfaces, where bitumen isnt as available.
NT
Bruce
Personally, I would get the usual sand and gravel and do it properly.
The proportion of fines in MOT Type 1 is far too high to make a decent
concrete. There is no chance of coating all the particles with cement
paste.
For that small quantity, if you have a 5mm sieve, I suppose you could
sieve away anything less than 5mm and use what remains as ballast,
adding some sand. But I have no idea what the results would be.
JimK
wrote:
erm....
WEAK as compared to .........?? gravel?
sucks up moisture.... how much ?
it's rock after all? go see malham!!
Cheers
JimK
Bruce
wrote:
No, it isn't. For cement bound macadam you need a very different
grading to MOT Type 1 sub-base - fewer fines.
The Natural Philosopher
So you think that chalk is as strong as granite?
Rock is a generic term.
Rock is VERY variable.
> Cheers
> JimK
JimK
> On Fri, 26 Mar 2010 12:09:35 -0700 (PDT), sm_jamieson
>
> >I need to make some concrete (approx 4-2-1) and I have a large amount
> >of MOT (crushed limestone I guess).
> >I only need about 0.1 m^3 of concrete.
> >Can I use the MOT as ballast, instead of going to B&Q and grabbing
> >bags of gravel and sand etc ?
>
> Personally, I would get the usual sand and gravel and do it properly.
>
> The proportion of fines in MOT Type 1 is far too high to make a decent
> concrete. There is no chance of coating all the particles with cement
> paste.
>
Evening Bruce.
Bollox!
I have had several tons of MOT over the years to dress our trackways
and i would 100% say it does not have as many fines as from sand in a
1:2:4 concrete mix.
Remember the "4" in the 1:2:4 refers to 20mm gravel, the"2" to sand -
in MOT you have many differnet sizes of grain all the way from say
40mm to dust.... the porportion of those sizes is the moot point. If
there were "too many" fines in MOT it would just behave like a "slurry
with lumps in" when used on tracks like ours ..... it doesn't, it
binds together esp. after vehiclular use - that is it's best property
which implies a decent spread of grain sizes to knit together.
Comparing to "all in ballast" aka "2:4" it *is* short on fines - hence
my recommendation to add sand to the mix.
Cheers
JimK
JimK
you get granite in your ballast then??
JimK
sm_jamieson
Well, I'm off to get some all-in ballast bags from B&Q. Better be safe
than sorry.
Strange how wickes is exactly the same price. £1.58
Simon.
The Natural Philosopher
> On Mar 26, 9:57 pm, Bruce <docnews2...@gmail.com> wrote:
>> On Fri, 26 Mar 2010 12:09:35 -0700 (PDT), sm_jamieson
>>
>> <sm_jamie...@hotmail.com> wrote:
>>> I need to make some concrete (approx 4-2-1) and I have a large amount
>>> of MOT (crushed limestone I guess).
>>> I only need about 0.1 m^3 of concrete.
>>> Can I use the MOT as ballast, instead of going to B&Q and grabbing
>>> bags of gravel and sand etc ?
>> Personally, I would get the usual sand and gravel and do it properly.
>>
>> The proportion of fines in MOT Type 1 is far too high to make a decent
>> concrete. There is no chance of coating all the particles with cement
>> paste.
>>
>
> Evening Bruce.
>
> Bollox!
>
> I have had several tons of MOT over the years to dress our trackways
> and i would 100% say it does not have as many fines as from sand in a
> 1:2:4 concrete mix.
>
I would agree.
> Remember the "4" in the 1:2:4 refers to 20mm gravel, the"2" to sand -
> in MOT you have many differnet sizes of grain all the way from say
> 40mm to dust.... the porportion of those sizes is the moot point. If
> there were "too many" fines in MOT it would just behave like a "slurry
> with lumps in" when used on tracks like ours ..... it doesn't, it
> binds together esp. after vehiclular use - that is it's best property
> which implies a decent spread of grain sizes to knit together.
>
> Comparing to "all in ballast" aka "2:4" it *is* short on fines - hence
> my recommendation to add sand to the mix.
>
I would also agree, but I repeat my point: no way is limestone as strong
as flint or granite.
MOT aint called 'crush and go' for nothing!
Its brilliant at load bearing once it HAS been crushed, but use
unsmashed in concrete it will not be nearly as good in compression as
proper ballast.
> Cheers
> JimK
>
>
The Natural Philosopher
Can do in some parts of the country. Ours is mainly flint. Calcium
silicate IIRC.
Limestone is calcium carbonate IIRC.
ballast and gravel are sedimentary deposits of alluvial or glacial
spoil. Essentially smashed up rocks of whatever was upstream.
The big stuff we call gravel, the small stuff we call sand. The very
small stuff we call clay, and the carbonates usually wash away and end
up in the sea.
A walk on any beach or any river bed thats currently dry-ish will reveal
almost no limestone or chalk of any description. Its flints, the odd
bits of sandstone, and granitic type materials.
Anything thats weak gets turned into fine and fine gets carried further.
Nature does a good job of grading gravel beds for us to use.
> JimK
JimK
mmm fascinating... if well known.
Even though OP has already decided to buy a few bags of all in ballast
(for the one mixerful of concrete) let's look closer:-
Density
Granite 2700 kg/m3
Limestone 2700 kg/m3
Modulus of rigidity (m)
Granite 24 GPa
Limestone 24 GPa
Unconfined compressive strength
Granite 100-250 MPa
Limestone 30-250 MPa
Shear strength
Granite 14-50 MPa
Limestone 10-50 MPa
Tensile strength
Granite 7-25 MPa
Limestone 5-25 MPa
You have to agree it would not have been a bad second to your granite/
flint/whatever in a mix - especially considering it was already
kicking around at the OPs...
I'll let you know if my road melts anytime soon (have you been to
Malham? noticed any major changes recently?)
Cheers
JimK
Clive George
> Can do in some parts of the country. Ours is mainly flint. Calcium
> silicate IIRC.
>
> Limestone is calcium carbonate IIRC.
>
> ballast and gravel are sedimentary deposits of alluvial or glacial
> spoil. Essentially smashed up rocks of whatever was upstream.
>
> The big stuff we call gravel, the small stuff we call sand. The very
> small stuff we call clay, and the carbonates usually wash away and end
> up in the sea.
>
> A walk on any beach or any river bed thats currently dry-ish will reveal
> almost no limestone or chalk of any description. Its flints, the odd
> bits of sandstone, and granitic type materials.
>
> Anything thats weak gets turned into fine and fine gets carried further.
> Nature does a good job of grading gravel beds for us to use.
Limestone isn't physically weak. Chemically, yes, but that's not
necessarily a problem.
The Natural Philosopher
^^^^^^^^^^^^^^^^^^^^^^^^^^
This is the killer though.
Limestone covers everything from chalk to the sort of jurassic
limestones, that are really hard. Almost marbles.
But what goes in MOT is NOT jurassic limestone, or even thr scraps left
over from making nice stone building blocks.
Its deliberately selected for its ability to compress and break under
pressure to form a nice compacted, yet still permeable substrate for roads.
So my contention that is way worse than granite under compressive loads
is correct. It could be up to 8 times weaker, and even if you take the
average, its considerably worse.
Let me know when you see a road with limestone chippings applied as a
wear surface as well.
Ive only ever seen flint or granite..
The Natural Philosopher
It is physically weak.
Or what's in MOT is. You can smash it easily with hammer in a way that
is not possible with flint. Flint shatters under a sharp knock. MOT
crushes under a heavy load.
If uyou lay a road with pure MOT and run a few 30 tonners over it, it
doesn't settle like granite or flint gravels do, it turns into a
continuous surface of crushed particles filling the gaps between the
larger lumps, and ends up quite smooth. I know, because I have done just
that before covering it in gravel.
The whole POINT of MOT type 1 is to BE physically weak in order that it
CAN end up as a stable free draining load spreading base although it
starts as lumps with gaps.
JimK
wrote:
compacted?
>I know, because I have done jus
> that before covering it in gravel.
>
> The whole POINT of MOT type 1 is to BE physically weak in order that it
> CAN end up as a stable free draining load spreading base although it
> starts as lumps with gaps.
MOT AIUI is a specification for particle sizes, it need not be a
particular rock.....you can even get it made from crushed
concrete.....not that weak then?
?free draining?
JimK
JimK
wrote:
> JimK wrote:
> > On 27 Mar, 13:16, The Natural Philosopher <t...@invalid.invalid>
> > wrote:
> >> JimK wrote:
> >>> wrote:
> >>>> JimK wrote:
> >>>>> On Mar 26, 9:56 pm, The Natural Philosopher <t...@invalid.invalid>
> >> silicate IIRC.
>
> >> Limestone is calcium carbonate IIRC.
>
> >> ballast and gravel are sedimentary deposits of alluvial or glacial
> >> spoil. Essentially smashed up rocks of whatever was upstream.
>
> >> The big stuff we call gravel, the small stuff we call sand. The very
> >> small stuff we call clay, and the carbonates usually wash away and end
> >> up in the sea.
>
> >> A walk on any beach or any river bed thats currently dry-ish will reveal
> >> almost no limestone or chalk of any description. Its flints, the odd
> >> bits of sandstone, and granitic type materials.
>
> >> Anything thats weak gets turned into fine and fine gets carried further.
> >> Nature does a good job of grading gravel beds for us to use.
>
>
> > mmm fascinating... if well known.
>
> > Even though OP has already decided to buy a few bags of all in ballast
> > (for the one mixerful of concrete) let's look closer:-
>
> > Density
> > Granite 2700 kg/m3
> > Limestone 2700 kg/m3
>
> > Modulus of rigidity (m)
> > Granite 24 GPa
> > Limestone 24 GPa
>
> > Unconfined compressive strength
> > Granite 100-250 MPa
> > Limestone 30-250 MPa
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> This is the killer though.
>
> Limestone covers everything from chalk to the sort of jurassic
> limestones, that are really hard. Almost marbles.
>
> But what goes in MOT is NOT jurassic limestone, or even thr scraps left
> over from making nice stone building blocks.
>
> Its deliberately selected for its ability to compress and break under
> pressure to form a nice compacted, yet still permeable substrate for roads.
> Let me know when you see a road with limestone chippings applied as a
> wear surface as well.
bridleways, BOATs, RUPPs ?
The Natural Philosopher
Simply to make boggy ground passable.
JimK
yes wear surfaces