reinforcement content

[nakedstone]

hey guys how is everybody. first time on forum, im in Sydney Australia and starting an architectural concrete company.
very new to counter top making, but very experienced in concrete and polished concrete.
my question is what reo is needed in a table that i am making for a client. thickness is 36mm , 1.82m long and .9m wide. in my opinion its a little thin for the length of the piece.
can someone help me out.

cheers guys.

[Alla Linetsky]

Welcome! No, your piece is not too large for the thickness, but you have to be careful with the concrete you use. As a bare minimum, you need a high-performance mix with a good pozzolan (you're probably most familiar with silica fume, but there are others as well), a generous amount of super-p to keep your w/c ratio below 33%, a viscosity modifier to avoid segregation and a shrinkage reducer to avoid curling. Then you need sufficiently thin steel reinforcement to fit inside the thin slab - use galvanized wire <5 mm diameter (most of us here use 3 mm if we're not making gfrc) and place it within 8 mm of the bottom of the slab. If what I've written is unfamiliar to you, please contact your construction chemicals rep to find out more and to get the products. You will find that most people on this forum make gfrc (glass fibre reinforced concrete), but with your background, you should probably stick to what you know and just make it a little better before learning something completely new.

[nakedstone]

thank you for your reply, very helpful.
just another little question, when you refer to a high performance mix design why do we not use a high performance mix for all applications. or do we?
thanks again

[Alla Linetsky]

We do use high performance mixes for all applications - most of us never pour more than 50 mm thickness, even when the edge looks much thicker. For anything over 50 mm thick, I poured a 37-mm shell when I was making conventional wet-cast concrete. And by the way, most people on this forum are americans and therefore not familiar with metric measurements.

[Mandala Design]

Yeah Alla,
50 million meters sounds pretty thick.
At least we are FREE!

[John]

FREE?

[Mark Celebuski]

Most adjustable wrenches are metric and americans know how to use them.

Mark C

[John]

Mark Celebuski said:

Most adjustable wrenches are metric and americans know how to use them.

Mark C

Now that is funny!!! I'll have to ask for one at Candian Tire one day and see how long it takes then to find one......Bwahahahahaha!!

[Jim Ralston URBAN CONCRETE DESIGN]

FREE????

We own nothing that cant be taken for not paying an unapportioned income tax, our life included, just remember Ruby Ridge and Weaver!

Soon there will be a tax on how often you breath!
Its to save the planet you know.....

Mandala Design said:

Yeah Alla,
50 million meters sounds pretty thick.
At least we are FREE!

[jschuler]

I heard that whole metric thing was just a fad......like bell botttom pants and tie dye. lolol

[Alla Linetsky]

So let me get this straight now: freedom = a measurement system that switches between base 12 and base 16 for whole numbers and base 2 for fractions. Maybe it's just a secret government plot to keep you so occupied trying to figure out how to subtract 2' 8-5/8" from 11' 4-3/16" that you can't think of anything else... A perfect mind control device.

And don't get me started on pounds and ounces, fluid and solid - I have no clue how much 3.85 oz is without a calculator.

[Jim Ralston URBAN CONCRETE DESIGN]

Yea third grade, we were all gonna switch over 1974.

[nakedstone]

just asking about steel reinforcement guys..... lololololol