concrete job got to be taken up and relaid - mesh query

[God mode restorations]

I understand what you mean.these sort of tasks can be a nightmare when acsses is limited.i think if it was me.i would brake it up including the sub base.smash it up in to small bits and reuse as sub base...it sounds a nightmare and you have a huge pile.but once you start you will be surprised how quickly it goes...pun it in and read concrete. If it's to large of an area you can do it in two sections and use re bar .

 

[gaz1]

heres my suggestion break a corner off or chisel the corner off and see how it looks if your lucky you maybe be able to shatter the pieces into finer pieces that can be reused in a mix as yours is way too sandy

colleges use sand and lime mix when teaching students and throw the mix back in the crusher mixer yours may do the same all you can do is try you could be really lucky and it will mostly go back into fine material that can be reused

if it does so and youve got kids give them hammers and let them smash to there hearts content

I reckon hes put 3-4 bags of cement into a ton bag when it should have been more cement used

 

[julianf]

That would be good if that was possible - im just worried about it not being a good job again.

Unless it goes right down to sand / aggregate again, i reckon id have soft pockets in the job again?

Id rather pay the cash for a disposal skip than have to do the job a 3rd time!


I think 4" over 6m x 2.3m is about 2.5 tonnes. Im guessing that's about 5 bags full of hardcore? Less if it breaks up more?

Ill need some at some point for another job, but noone wants to store 5 dumpy bags of hardcore in a terraced house back garden.



Ive considered splitting the job into two halves. Dig out the first half - stack the spoil on the other half. Re-lay one half, move it across, etc.
Like those kids puzzles where you have to move the tiles about to complete the picture.

I dont really want it in two halves though.

 

[DecK]

I know you said you can't go any higher but any chance of getting away with using a 10mm deep grout layer on top of what you already have. Unless I've picked it up wrong its more surface finish you want to correct. The grout wont look like concrete but it would provide a decent wearing course for lack of a better term.

 

[God mode restorations]

You have good hardcore there with what you have. A bit of time taking it up and smashing it in to small pieces will be good hardcore. .you honestly don't need to buy more.

 

[gaz1]

as long as it breaks back down to sand and aggregate again it will be sound to use any large solid lumps you just dont use in the mix

hell you can make a concrete mix out of old pointing, sand and cement

my advise break up a tester piece and then you can go from there

as a builder myself and coming into the job id order a skip break it up and skip it then remix a whole new batch the proper way and relay it

just post a photo of the broken up tester on site and even i can tell you if its ok or not but a sledge hammer dropped onto the poor mix should shatter it thinly or lucky it returns back to its sandy and pebble mixture easily

 

[the snooper]

You have good hardcore there with what you have. A bit of time taking it up and smashing it in to small pieces will be good hardcore. .you honestly don't need to buy more.

unless he can turn it back into sand and gravel he would be left with lumps of soft mix which will cause it to fail again in the future

 

[julianf]

Im getting confused here -

Hardcore (subbase) on the existing job is smashed up bricks, old concrete, etc.
Then 4" of duff concrete on over the top.

If i take it up, some of the existing hardcore (subbase) will come up with it, but most will stay down - just will be disturbed.

So, ill have a load of duff concrete in dumpy bags, with some of the original subbase mixed in.


I would think this would be good for subbase on another job. It will be soft, but if its compacted well, possibly on top of some more solid material, it will, id expect, bind well?

If i need more subbase on this job, i would think it will be fine, providing its hammered in well.

But, as for using this in the new concrete mix for the surface? Id be worried about that.

 

[brightspark]

bite the bullet dig it up and re lay it .simple azz

 

[God mode restorations]

Im getting confused here -

Hardcore (subbase) on the existing job is smashed up bricks, old concrete, etc.
Then 4" of duff concrete on over the top.

If i take it up, some of the existing hardcore (subbase) will come up with it, but most will stay down - just will be disturbed.

So, ill have a load of duff concrete in dumpy bags, with some of the original subbase mixed in.


I would think this would be good for subbase on another job. It will be soft, but if its compacted well, possibly on top of some more solid material, it will, id expect, bind well?

If i need more subbase on this job, i would think it will be fine, providing its hammered in well.

But, as for using this in the new concrete mix for the surface? Id be worried about that.

You got it..me personally I would smash up reuse as your sub base....pun it in...then relay fresh concrete..

 

[the snooper]

get rid start fresh 5 to 1 mix, don't stand thinking of saving cash using a kiddies beach spade for adding the cement it doesn't work

 

[gaz1]

a cement mixer holds 12 shovels of aggregate/sand mix the same amount a wheel barrow can wheel

4 to 1 id use and that changes if im colour matching to other cement

 

[I'm getting on a bit]

Julian F tomorrow I will show something you will find interesting

It's an accessory that fits my breaker so I can recycle hardcore for base Titan 15kg

 

[mike os]

When you remix toy should be using about 500kg of cement in that mix

 

[mike os]

Personally I would not reuse the material as you can't accurately mix the ingredients which will just give you more problems

 

[julianf]

When you remix toy should be using about 500kg of cement in that mix

...which would line up pretty well with the 23-off 25kg bags off cement i purchased for the job first time around.... which i then had to take back to the store!

Personally I would not reuse the material as you can't accurately mix the ingredients which will just give you more problems

You mean not as sub base either? To be sure, i dont want to risk mixing it with more cement for the top.

 

[mike os]

Sub base is fine, then blind with sand and put a membrane in, when mixing dont use too much water, more porridge than soup

 

[I'm getting on a bit]

http://www.mig-welding.co.uk/forum/media/imag0248.8775/

The base of this is a billet of steel 100 x 100 the springs stop it falling off

The point on the er point was ground on my surface grinder.

The clamp was made on the Bridgeport mill the two cap head screws were used to space out the gap with some washers before boring to size of the point so its a nice snug fit.

I have already tried this out with a piece of 50 mm steel.

Apart from falling of and being a bit on the small side it worked well

 

[julianf]

Am i right in thinking the mesh should be at least 2" from the surface - or does it need to be more?

If i can hook out the existing mesh, ill reuse that - if not, ill buy again.

This will be a 4" slab again. I couldnt easily go thicker, but, as i understand it, 4" should be fine.

The area around is 2" of concrete laid on a sprinkling of pea shingle (ie a single layer - about 10mm) on top of soil - and its been like that for years with only minimal cracking, so the ground here is pretty stable.

 

[nick952]

If the base is for a shed use a ratio of 3(20mm Coarse Aggregate):2(Sharp/Concreting Sand:1(Cement) mix . If it's exposed to the elements use a 2.5:1.5:1 mix of the same.

Importantly use some sort of Gauge to measure out the above (e.g. a Builders bucket) to keep the mix accurate and if you really want to be pedantic, measure the quantity of water used in the first mix and add the same to subsiquent mixes.

I also avoid using an all in one Ballast mix (Coarse Aggregate and Sharp Sand ready mixed in the bag) Dumpy Bags, as the sand tends to end up washed down into the bottom of the bag, resulting in an uneven/poor mix (unless you can mix the Whole bag in one go).

You are correct that the mesh should be a Minimum of 2" below the surface (also applies to above the base and from sides).

Nick.