- Concrete advice needed
I have just put a metal walled pool into the ground. I now have to pour in a concrete collar around it to prevent any earth cave-ins destroying the walls whenever the pool is emptied.
I have read that the ideal mixture for concrete is 1 part cement, 2 or 3 parts sand, 3 parts stones. As this will be more of a gap filler rather than a structural piece, will I get away with throwing a load of rocks and smashed up paving stones into the mix as I pour it? Can I increase the sand or stone ratio? If anyone can share some experience I would appreciate it.Posted 2 years ago
Actually, the manufacturer only states “suitable for above ground or in ground”. I read that if you live in a sand area you need the collar, and I live in a clay area, which does not necessarily need it. Therefore its really just a gap filler to stop things moving.
I hear you though, if I am going to do it might as well use the standard mixtures.Posted 2 years agothelawmanMember
Historically, 1-2-4 or 1-3-6 by volume mixes were the de facto options for pretty much anything; the former for anything structural, the latter for owt else. So in your case, 1-3-6 should do fine. It’ll produce a compressive strength around 25N/mm2 if you make sure it’s well mixed and give it a week or so to set properly. But get some decent graded 5-20mm coarse aggs and a suitable grit sand to go with your CemI (OPC). Don’t just go with ‘some smashed slabs or rocks’ as there’s a bit more science to it than that to do it right.Posted 2 years ago
Thanks Lawman, 1-3-6 it is.
Trailrat – its not so big, 4.5m diameter, with between a 10 and 20cm gap around it at the moment. So I’ve got about max 3 cubic meters to make, probably more like 2 cubic meters. The problem is that I can only get a minimum order qty of 6 cubic meters delivered. So intend to borrow a mixer and get on with it.Posted 2 years agocoolhandlukeMember
6m would be a minimum order from a batching plant and then into a “normal” cement lorry for delivery,
There will probably be something like spot mix or mix it mate type company that will literally pull outside your house in their lorry and mix any amount you need.
Posted 2 years agowrightysonMember
^^^not really^^^Posted 2 years ago
Minimum to batch in a standard 6 wheeler 6m truck is usually 1m as that’s the standard amount required for it to actually batch and mix properly depending on whether it’s dry batch plant etc. However over here you will pay an “uncarried” levy of around 40 quid a m3 on top of the 1m3 you actually want. Cost for comparison is well worth doing these days as we’re paying 32 quid for a bulk bag which usually carry around 800-850kg. So per cube you’ll need 2 1/2 of these plus approx 16 bags of op so that little lot addded up is about 130 plus vat per m3. Do the math then ask the questions on part loads.natrixMember
As CoolhandLuke said your best bet is to get in a mix on site company. If you can’t find one through google, get in touch with obv (the Austrian Concrete Society via http://www.bautechnik.pro/EN/Vereinigung/Ueber_uns )Posted 2 years agoredmexMember
Trying to pour wet concrete down a 4″ to 8″ gap you will need a good slump and will be messy once your biceps are done after twenty mins. When concrete comes out a lorry you get overfilled barrows as the drivers want to move on soonPosted 2 years ago
I’d dig a bigger hole at one end and get a vibrator not an Ann Summer catalogue one but a poker
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