Curing

[david s]

Re: Curing

Yes, but only if you keep it wet. Read the info again.
http://www.concrete.net.au/publicati...f/Curing06.pdf

[brickie in oz]

Re: Curing

Portland based concretes must be cured with continuous moisture to reach useful strength. Typically 7 days minimum.

Your graph just shows it gets stronger over time, which it does.

[Paul in Rockwall TX]

Re: Curing

Although I haven't done homebrew, I'll reiterate my support for heatstop 50. excellent product, no cracks. I slow cured with wet towels and blankets for a week or so, then air cured for 10 days before starting the fires.

I'm running real hot, and no issues whatsoever inside. I was a little surprised, because I expected internal cracks after reading the forum and given that I'm a rank amateur. but nothing.

If it's available in your area, (mine was $50 per bag), I'd use it.

Paul

[Neil2]

Re: Curing

Portland based concretes must be cured with continuous moisture to reach useful strength. Typically 7 days minimum.

[GianniFocaccia]

Re: Curing

How does the homebrew recipe of 1-3-1-1 (portland, sand, lime, fireclay) work out strength-wise?

[brickie in oz]

Re: Curing

Its far easier to repoint a few joints rather than replacing a brick.

[david s]

Re: Curing

Yeah,
Because the oven is moving stresses build up and something is probably going to give. Like Brickie said you'd prefer that your mortar failed before the bricks. So the mortar should be weaker than the bricks it joins. However you don't want it too weak.

[GianniFocaccia]

Re: Curing

DavidS,

So is it the potential for oven movement that it is advised to minimize or eliminate inside mortar joints? I thought it was because portland cement begins to break down at 500F. There is a high percentage of builds on the FB site that have little or no exposed joints in the oven interior with 1"+ gaps on the dome exterior.

John

[david s]

Re: Curing

yes, and this is the reason why many brick kilns have no mortar between the bricks. Same goes for our oven brick floors.

[brickie in oz]

Re: Curing

The problem with having the mortar too hard is if there is ever any movement the bricks crack instead of the joint.

[david s]

Re: Curing

[QUOTE=david s;111244]There is confusion about the term "curing".
Firstly, when applied to freshly laid concrete containing Portland cement: it should be kept moist for a week. Concrete not treated this way will not achieve its max strength. This applies to anything made containing Portland cement. It is impractical in many instances to keep a slab moist for a week, so it is often not done, however the resulting strength may be down as much as 60%.
As I said, it is impractical in many instances to keep it moist. However all prestressed concrete beams, pipes etc. are manufactured in this way to gain max strength from the cement used. If possible why wouldn't you make it as strong as you can. The other alternative is to over build it and hope for the best.

[brickie in oz]

Re: Curing

I'd hate to be in the ocean in a crumbly concrete boat. aaahh!

Wouldn't it be Yarhhhhhhhh?

[brickie in oz]

Re: Curing

Sorry David but I have to laugh, theory is one thing but practice is entirely a different beast.

Never in 30 odd years in the trade have I seen any concreter covering their slab with plastic to cure it, Ive seen slabs laid one day and the timber frame erected the next.

Im sure the same concrete slab is still there doing what its supposed to do 20 years on.

[david s]

Re: Curing

Boats made from ferro cement are carefully cured for 28 days for the same reason. I'd hate to be in the ocean in a crumbly concrete boat. aaahh!

[david s]

Re: Curing

you need to read the info from Cement Aust. I was actually wrong about strength being down to 60% concrete air dried is actually only 40% of full compressive strength.

http://www.concrete.net.au/publicati...f/Curing06.pdf