IGX

I have got a bunch of questions on concrete mix that aren't easily answered through searching.

The man in black wrote:I have got a bunch of questions on concrete mix that aren't easily answered through searching.

I helped pour a basketball court and part of a driveway when I was a teenager so am pretty much an expert at this kind of stuff. Ask away.

Haha! Everyone is an expert on the internet.
Why would I choose to select gravel or crushed limestone for a coarse aggregate?
In a mix that is 50/50 Portland cement and slag cement, what effects could I expect to see by dropping that to 45/45 and adding 10% silicia fume, besides a stronger concrete?
How much strength loss in terms of psi can I expect to see by bumping the air up to around 5%?
How should I adjust the mix components when bringing the air up to around 5%
What are the benefits of eliminating air from the mix besides a denser concrete?
For reference, this is all for making atlas stones.
Also, why am I such an analytical freak who isn't happy with Quickrete 5000 and calling it good enough?

The man in black wrote:Haha! Everyone is an expert on the internet.
Why would I choose to select gravel or crushed limestone for a coarse aggregate?
In a mix that is 50/50 Portland cement and slag cement, what effects could I expect to see by dropping that to 45/45 and adding 10% silicia fume, besides a stronger concrete?
How much strength loss in terms of psi can I expect to see by bumping the air up to around 5%?
How should I adjust the mix components when bringing the air up to around 5%
What are the benefits of eliminating air from the mix besides a denser concrete?
For reference, this is all for making atlas stones.
Also, why am I such an analytical freak who isn't happy with Quickrete 5000 and calling it good enough?

Yeah, that's what I would do.

Maybe analysing the shit out of how to make them, is the most fun your personality type will have with Atlas stones.

There was a time when I thought I was going to make a concrete countertop and got read up on it. Sounds kind of similar in terms of strength required, material choices, etc. Google on that, there's a lot on the nets about it.

You may end up with a more fragile mix.
Follow directions and change ball weights by size and core (foam core or lead core ect)

Maybe quit trying to reinvent the wheel and call Steve Slater and talk to him about it? Or just go to a concrete place where someone might really know stuff like this about concrete :)

Gorbachev wrote:Maybe analysing the shit out of how to make them, is the most fun your personality type will have with Atlas stones.

Actually I am trying to make money at this which is why I care about being so analytical. If it were just for my own use I would use pre bagged stuff and if it ever fell apart I would just make another one and get on with life.

I have talked to Steve Slater and watched his video and it seems like he just uses pre-bagged stuff, or keeps his real mix a secret (the world record Arnold stone isn't made with bagged stuff). When I described the size of the stones I get in pre bagged stuff to a concrete technician he told me I could get a lot stronger stones just from using larger aggregate which got me to pursue a better option.

Word is, Slater's stones aren't the nicest ones on the circuit by a fair margin either.

I applaud your efforts to develop a better mix. Did a site visit at a steel plant a couple weeks ago and they noted one of the by products of the process, steel scalings, is a product added in industrial use concrete for strength and wear tolerance. Got me thinking along the same lines as you.

I've done several counter-tops as well. My take it that shit is easy compared to an atlas stone. A lot of guys are using low shrink precision grout in that application without rebar and it holds up really well but waaay too spendy for a stone and too slick as well.

The important thing is that you pour a thick enough slab so it doesn't crack when the body decomposes.

don't you have any questions about rebar--size and configuration--and wire mesh?

how are you going to make sure you get a perfect circle for a form into which your pour? (you'll use lasers, not tape, won't you?)

how do you finish a stone all the way around? some of the material will be inside the form and inaccessible. wont this be rough?

i think you should to go to a granite quarry, buy a block, get an eyetalian stonemason to shape it and finish it. that would be a stone worthy of atlas.

dead man walking wrote:how do you finish a stone all the way around? some of the material will be inside the form and inaccessible. wont this be rough?

25 year old Demi Moore, a pottery wheel, and a Righteous Brothers album.

A civil engineering specialization in structures would be able to answer all of these questions, and more, in about two seconds.

You should email your local university if you don't know anyone personally -engineers love this kind of shit.

Gorbachev wrote:Maybe analysing the shit out of how to make them, is the most fun your personality type will have with Atlas stones.

:snigger

I've used bagged stuff stretched with fiberglass rather than sand or gravel. Look into that and you might find just what you're looking for.