I wouldn't go near any poured footings for at least a week, Karl. As important as they are, I definitely wouldn't fool with it.
Less than 50%, as stated by all the concrete guys I've talked with. I've seen fence post crete jobs broken < 2 days, splitting the cylinder of crete in half when kids went climbing the crossbars before pickets went up.
As I recall, just built a 26x70' steel building with 6" nominal floor and beams and deep wells all around.
The cement guy stated 60% in 48 hours. They were driving a massive beam fork lift up on it without issue, moving steel beams and heavy iron. The bolts were tightened, but not hard, had to get the other steel up in case it had to move a bit - wiggle room...
It depends partly on the formula and such. Mine was 7000 psi cement. I have a 150 gallon fish tank 12" from the edge of the cement but it sits on a pier the size of an icebox sideways and standing! My safe is on a pier that is the size of a freezer downwards. We wanted to get enough mass that it would not rotate under load.
Martin
Well ... I'm bedding the floor stones in a mix of 5 parts masonry mix , 1 portland , 3 sand , and 1thinset mortar . This gives a mortar that's really sticky when mixed on the dry side and stays very plastic as it sets . Makes it possible to adjust a rock that's been set for a few minutes without breaking the bond . I'm also laying on top of a layer of tarpaper so differential expansion doesn't tear things up . I'll be covering it with plastic when I finish filling the joints . Then , it'll be the wall ... which is a totally different technique . It'll also be covered with a vapor barrier for a couple of weeks minimum . Actually , I was being sarcastic when I asked that question ... I still remember when my Grandpa poured the floor for his garage , several hours after they finished troweling it he scattered some straw over it and covered it with tarps to control evaporation . I had to be like 10 or 11 , which would put it around 1962 or 63 ...
That's sure nice. I had a fun time with mortar when I did my first cobblestone walkway set in mortar, but it has stood the test of time (7 years) so far. It's harder to get a single stone's surrounding mortar to reliquify for resetting, but it's doable. I used a thick piece of wire made into an L-shaped hook to lift the low stones to level, bouncing them up-and-down to get the mortar back under them.
Good!
How do you like the Advantech over regular ply?
Wow, they had concrete way back then? ;)
I set (actually, reset) my first fake stones yesterday. Four pieces of stone veneer (limestone-like hypertufa) onto the outside of a garage wall. Researching adhesives for it, I could either buy a $45 bag (50#) of thinset or use LiquidNails. I chose a tube of LN for $2.39. It didn't even pretend to hold the stone up to the mortar, so I looked around and asked the lady for a large plastic bag and some old rags or something. She had 4 boxes of winter clothes in the garage so I used some of those. I filled the bag with clothes, tossed loosely into the bag, then squished it up against the stone, using the other boxes of clothing to press against the bag. Worked just great! Steady firm pressure all over the face of the stones, holding them to the wall for the hours until the LN set up. I was applauded for my ingenuity, which is always nice.
It's great . Very stable , more rigid than plywood , and it doesn't swell up and start shedding if it gets wet . This floor got rained on twice before I got the roof on , no damage at all . Don't even think you can hand-nail it though ... I used my framing nailer .
And even before , if you believe history !
Ingenuity indeed ! I'll have to remember that trick , bet it'd work on reattaching almost any veneer product .
I used a LN stone/block adhesive to repair headstones about 10 years ago. These were the old marble stones. Some were old weathered breaks. Figured there wasn't much to lose. Cleaned off the joints, applied the goo and stuck them together. Had to brace them in place. Came back a week later and pulled the braces. Stuff is still holding just fine today! Only issue was that the glue was an amber color, I took some marble dust and mixed it with some clear epoxy and "painted" the glue. That has taken the weather very well.
The only time a LN branded product has failed me, I'm pretty sure the tube was ancient. In that one I glued some treated lumber up and the joints failed.
Italian contractors were pouring concrete in 300 BC, and it still hasn't completely cured.
That's good reason to be wary of Italian contractors. "We'll be back to finish the job when it's completely cured." d8-)
"Ready mixed concrete was first used in Germany in 1903"
-- etd.lib.metu.edu.tr/upload/12609528/index.pdf
I assume that's the type this thread has been referring to. But even the Sumerians described concrete. The Sumerian timeline dates from 3000 BC.
Portland cement is "regular cement" in the US. In Western Europe, they often mix in a large percentage of Pozzolan. Their strengths are similar but Portland cement cures faster.
At least by 1000 BC, the ancients were making Pozzolan cement in much the same way a lot of it is made today: fine-ground, reactive types of volcanic ash, mixed with slaked lime.
Pozzolan has been used for thousands of years, while Portland cement has been around for about 150 years.
I usually screw things down, so I'd likely drill prior to screwing. I've seen it advertised in my building mags and might have tried it before now, but the closest source is Medford. That's an hour R/T.
Imagine that!
I didn't have a weather balloon handy, so I settled for wadded clothes.
Why is it sick?
excessive dehydration?
:)
Pozzolan, being made with volcanic ash, has the unique ability to cure in salt water. Piers and mooring points were done by the Romans and the Japanese before and during WWII.
Martin
You can, but you'll bend a lot of the specified nails unless you have some superhuman ability, or predrill, perhaps. I did 1000+ square feet hand-nailing with the specified ring-shank nails and some volunteer helpers, and we learned to just give up and yank & try again when the first bend took place, as there was no getting it right after that. It's also glued down.
I neither own nor want to own or rent a nailer. Hammers suit me fine.
Here: someone said in a: "textbook that saltwater will work, but the total compressive strength will be 10%-15% lower" --
Curing IN salt water is different from mixing WITH salt water
You seem to be a history buff on concrete...
How is it that Henry Flagler could build concrete piers in the ocean
100 years ago in the FL Keys and have the concrete still be in great shape. Meanwhile everything built more than 20 years ago is falling apart in the Keys.Karl
I don't know the answers to that one, Karl. My interest in concrete is mostly about two things: post-tensioned structures and ferrocement. I've just picked up a few historical tidbits along the way. I have a really great book on ferrorcement (among several others) that took me most of a year of spare time to read.
Back in Flagler's day, we overbuilt all kinds of sructures, because we didn't have the engineering to build them closer to the limits. I'm just guessing, but it could be something like that.
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