Very cheap recyceled sand

[Captain Concrete]

Hi all, I have been offered 1000s of tons of sharp sand, its very cheap and comes from road sweepings. The sample looks ok 2 questions:
1, has anyone tried recycled sharp sand
2, where dose it all come from

Its for use in making concrete and I would only use it in the weaker mixes.

[Brucieboy]

Be very careful when using recycled sand in concrete. You say it comes from road sweepings which would suggest it's some form of crushed rock fines not sand. If it is sand, my guess it originates from construction demolition waste. There are numerous companies out there with recycling plants that take such waste and recycle it into coarse and fine aggregate as well as topsoil.

From my experience the recycled "sand" tends to be very silty, generally finer than a good quality sharp sand and sometimes contains contaminants detrimental to concrete durability. It usually has a higher than normal water demand which is likely to result in lower strength and increased shrinkage.

It's cheap for a reason so my suggestion is you check it out thoroughly first before using it, even in low grade concrete mixes.

[GB_Groundworks]

If your selling it then you need some random samples batch some up test cube it and have it tested, we now make cubes of all our structural pours and document them.

[lutonlagerlout]

why take the chance captain?
our volumetric blokes buy stone and concreting sand separately for the wagon
so the mix is always consistent
the only issue I ever notice is if you have first drop the water has tended to settle to the bottom of the wagon making the last couple of metres wetter
they buy in huge bulk as I am sure you do
so why risk your good name?
LLL

[dig dug dan]

I have just done a big job which involved removing 140sqm of block paved drive and replacing with gravel. Also I had to lay some paving, and new drive edges. I re used the sand under the blocks for slab laying and mixing with 10mm shingle for the haunching of the drive edges.
it was ropey stuff, but fine for what we were doing with it. I wouldnt want to use it for concrete jobs though

[DNgroundworks]

Be very careful when using recycled sand in concrete. You say it comes from road sweepings which would suggest it's some form of crushed rock fines not sand.

Erm, is sharp sand not crushed rock?

[Brucieboy]

Not really. Crushed rock fines is what it says - the fines / dust resulting from the process of crushing hard rock such as granite or limestone. Sharp or grit sand is either dug from a pit /river or dredged from the sea.

[digerjones]

I've seen it recycled from filter beds from sewage works

[lutonlagerlout]

sharp sand is quarried round these parts
leighton buzzard and st albans
LLL

[Brucieboy]

Dylan - I've used incinerated sewage sludge ash (ISSA) before and also coarse and fine incinerated bottom ash (IBA) the latter a by-product from municipal waste incinerators. Neither are particularly good for making quality concrete although they are sometimes used in aerated blocks.

LLL - the reference to pit can also be read as quarry - there are some regional differences in terminology. I used to live in Bromham (near Bedford) so I'm very familiar with the all the sand / gravel operations and ready mixed concrete plants in your area.

[Captain Concrete]

We only use the best sand and stone in our mixes but was thinking about recycled sand for foam concrete and some of the weaker mixes, you guys have confirmed my gut feeling, don't think I will bother cheers All