# Forum Home Renovation Landscaping, Gardening & Outdoors  Weight/Volume of blue metal

## jeremy

Hi all, 
 I'm attempting to estimate the amount of 10-20mm blue metal I need for behind a retaining wall.  How much (approx) does 1m3 weigh? 
 Also, is there any issues using a recycled concrete product instead? 
 Cheers,
 Jeremy.

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## echnidna

roughly 2 tonne

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## DavidG

Gravel, loose, dry 1.52 tonne/cu  http://www.reade.com/Particle_Briefi...ec_gra2.html#G 
No problems.

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## vsquizz

6 to 8 mm is almost 2400 kg/cube so Bob is probably on the money.  
Cheers

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## Forest Gump

A few of the guys have given pointers in regards to weight.  
Bluestone does vary in weight, depends on the quarry it comes from. It could be lightweight stone or heavy weight stone. Ask the supplier. 
There is such a thing as lightweight concrete, which of course uses lightweight aggregate/stone etc. Can't remember what they use it for. 
The concrete recycler would give advice on suitability of use for retaining walls. I don't see why not, providing it's a coarse crush, not too many fines. 
Daniel

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## gatiep

Quote:"There is such a thing as lightweight concrete, which of course uses lightweight aggregate/stone etc. Can't remember what they use it for."   
How about lightweight structures. 
:eek:

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## Lucas

> There is such a thing as lightweight concrete, which of course uses lightweight aggregate/stone etc. Can't remember what they use it for.

  Hmmmm maybe lightweight concrete is for boats ...... Forest

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## Rocker

Solid uncrushed basalt (= bluestone) weighs around 3 tonnes per cubic metre. The weight of gravel or aggregate depends largely on the shape of the particles and therefore the proportion of empty space. I would estimate that coarse gravel would be between 2 and 2.5 tonnes per cubic metre. 
Rocker

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## Gingermick

Whatever you do, make sure water can't be held behind the wall. A coarse draining layer and some sock drain will work. Blue metal will pack down quite hard and stop water flowing through so don't use it at the bottom behind the wall.

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## Dan_574

I would only use aggregate for behind the wall, I dont know what you have up there but here in Vic I havnt seen crushed concrete as an aggregate only as a crushed rock and it has lots of small particles in it which would trap water.  Try some large scoria, its lighter than blue metal.

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## Forest Gump

gatiep 
I left myself open there, re lightweight concrete, re lightweight structures etc. 
I think they use it for precast or tilt panels. But remember it is not as strong as normal concrete with a denser aggregate. 
Actually getting back to retaining wall aggregate. Some companies ask for stabilized aggregate. The aggregate has about 3% cement mixed in with the stone to give it that stabilized affect. The road companies use it under the kerb and channel. There is normally a aggi drain there. Just some more useless information from me, boys and girls.   
Daniel

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