View Full Version : Porous high density concrete

Cliff Rohrabacher
02-21-2009, 12:23 PM
I have a small ( & small in geometry too) DIY application I'm fiddling with that'll require a concrete that can:
1.) Tolerate about 1000 Def F over extended periods lasting months.
2.) Be highly dense with a high pressure strength (no numbers available)
3. Be porous so to wick away and allow fast evaporation of any ambient moisture to prevent spalling from bursting bubbles of trapped moisture.

The only moisture (after cure) the product will see will be that which it will wick up during high humidity situations but no direct contact with lliquid water will occur.

I figure I can use a finely ground silica for the aggregate instead of sand (much like the silicates Custom Products Co uses in it's epoxy mortar).

But the wicking porous concrete part has me stumped. I know about porous concret for drainage but, I haven't a clue how they achieve it.

Any one know about porous concrete?

Cliff Rohrabacher
02-21-2009, 3:16 PM
It doesn't have to be concrete if there were an air dry ceramic non-firing that'd work too. I just don't know of any ceramics that'll do.

Brian Effinger
02-21-2009, 3:19 PM
I think you are looking for air entrained concrete. Usually this is used for situations where the concrete will be exposed to the weather and freezing situations, so I am not sure it will work here. http://www.cement.org/basics/concretebasics_airentrained.asp


I just saw your last post, Cliff. An alternative may be fire brick - the stuff that is used in wood burning fireplaces.

Stephan Postmus
02-21-2009, 5:25 PM
Years ago the ready mix producer I worked for had a concrete mix that would withstand very high temps. I'm not sure of the technical name for the concrete, but we used fondu cement and trap rock aggregate. We used to place concrete in the steel mills for the hot steel to sit on after it was made. (However they do that, making the steel, I have no real idea). I know that the concrete wasn't cheap, usually double or more the cost of regular concrete. Try googling heat resistant concrete or the like.

I know that aggregate made from the the slag by product of steel making is very porous. We would use that in concrete as well.


Greg Cuetara
02-21-2009, 11:05 PM
Can you give us an idea what you are trying to do? 1,000 deg. for a few months is a lot of temp for a long time.

Dick Strauss
02-22-2009, 10:54 PM
Glass kiln?????

Tom Veatch
02-22-2009, 11:33 PM
Aren't "be highly dense" and "be porous" somewhat mutually exclusive?

Chris Padilla
02-23-2009, 12:17 PM
Tom, I was thinking the same thing only "oxymoron" came to mind! :D

Whatcah doin', Cliff? You got me all curious! :)