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Everything You Ever Wanted To Know About Concrete* (But Were Afraid To Ask)
In the comments on another post, I mentioned it would be nice if someone talked about concrete — that noble material of the Pax Romana — so I might sound at least slightly knowledgeable on a topic here for once. Sure, it’s not as fun a topic as Same-Sex Marriage or drug legalization, but it may also help me in Dime’s contest this year for worst poster!
A little background: I am one of the owners of a commercial and industrial concrete construction company that does work all across the southeast and as far west as Oklahoma. Yes, it’s exactly as glamorous as it sounds! Concrete is a basically a mixture of cement, aggregate, and water. Yes, cement is an ingredient of concrete, so now you know if someone refers to concrete as “cement” it is appropriate to point and laugh.
Fellow member Captainpower was gracious enough to ask a few questions that I will try to answer adequately here:
Q: Are there different types of concrete?
A: Absolutely! It varies in both compressive and flexural strength, abrasiveness, color, reflectiveness, weight, etc.
Q: What’s the difference between good and bad (or proper and sloppy) concrete mixes and application?
A: I think this question is about the “slump” or “wetness” of concrete when it is first placed. The key measurement in a mix design that many times the “slump” indicates is the water/cement ratio. The concrete is weaker, both chemically and because of material segregation, when that ratio is too high.
Q: Are there any craftsmen left, or is everyone in it for a quick buck?
A: Yes there are some very talented craftsmen out there! It’s actually a pretty tough business to make a quick buck in, though I know residential contracting can attract some unsavory types that will try to take advantage of the unwary homeowner.
Q: Is concrete technology still progressing, or do we pretty much have it mastered since forever?
A: Concrete technology is constantly evolving and advancing, and the Romans would recognize very little about modern concrete, other than that it hardens. There are many chemical admixtures that can make concrete behave in various ways, which means it can be applied in all kinds of different ways. It can have its set time delayed indefinitely, or can be made to set almost immediately. It can be made to flow horizontally like water without losing strength, made waterproof… the list is endless.
Q: What’s better than concrete? What’s worse?
A: It depends on the application. People use concrete in all types of construction. Roadways, precast, structural building elements, kitchen counter tops, even concrete canoes. Does it make good carpet? Not especially, but a polished concrete floor that is colored or stained can look pretty darn good!
Anyone else have questions? The floor is open.
Published in General
You don’t know how long Big Con has needed an enforcement wing! We sill soon take over CrunchyCons and make paleoCons nervous! Muahahaha Bunch of RINOS!
It’s one of the wrecks featured in my upcoming “Texas Shipwrecks book. I suspect underwater concrete existed in the 1920s, since the Romans had it, but I suspect shipyard workers asked to repair the ship did not have knowledge of it. To them ships came in two flavors – steel and wood. (For all I know they tried to bolt a patch on.)
The shipowners were keeping it afloat wit a number of oil-fired pumps, and ditched it because they did not want to pay the rental or fuel for the pumps. There was a lot of war surplus at the time.
Seawriter
How does one start a concrete business? Let’s say maybe in the state of NC?
Very very carefully. ;)
Boymoose, thought you died in a diving accident. Sorry.
I’ve been so busy this week that I haven’t had time to weigh in on this convo. Inexcusible, as I sell diamond blades. If you ever need to cut concrete (or tile, or asphalt, or glass) I am your chick.
They call me the blade babe (well … my husband does)
Like Annefy, above, I’ve been busy (and travelling) – but I’m a certified amateur concrete geek, so I’m loving this to death. Has there been any discussion of controlling cracking in high temperature pouring environments?
To: Mr. Concretevol
Thanks for answering my questions a few million comments ago. I meant to hit reply and thank you when I first saw your answer; but went out for lunch, and when I came back I’d lost complete control of this thread. Carry on!
We did discuss some extreme weather pouring techniques. I would be happy to discuss further so you don’t have to search back through the comments. lol I will come back when I have a little more time if you like and talk about it. One quick point….low humidity and high winds are even worse than temperatures when it comes to slab shrinkage cracking. Of course those two plus high temps are even more delightful!
Cheers, CV
Simon T!
Not a problem man, glad to do it. I know how you feel about the post, I went to work yesterday morning at around 4 am and wasn’t able to check in til around 9 I think and when I logged in on my phone it looked a lot like my post was on the main feed. lol It’s been fun though and am still checking periodically for actual questions so anyone can still ask one no matter how many comments have come before and I will try to answer them.
Concrete can be buried underground for structural reasons, or use above ground for beauty. It is an amazing product.
Jojo wins, “cracked and going to crack”
Simon that was no accident.
10, how is this post not about sex?
Concretevol, I gotta try that stout. Your screen name reminds me of a field name on a material take-off. As in concrete volume.
Boymoose,
You need to get out more or stay home more. I can’t decide which.
Here’s a question: in the background of the headline photo are numerous blocks. Are those the remainders from slump tests?
Ok, now I really gotta get some pricing from you ;-)
Man there are some great Stouts and Porters this time of year (always seems like a winter beer to me). My next post may have to be on craft beer! Oh yeah and I hadn’t thought of that about vol meaning volume…..My meaning is Tennessee Vol but either works I reckon. :)
That’s a great question Joe, I was wondering what those were also. My original headline photo was the concrete structure now shown further down in the post. The higher powers decided to change my post title (better) and photo so I don’t know what’s in it. Those probably aren’t slump test remainders because that is usually just a pile of concrete dumped out of the cone or wheel barrow. Those look really square like a they were formed that way…..
The other side of that is cold weather concrete. No matter what that usually involves late nights like this photo from last night.
This is awesome! I’ve poured two concrete slabs in my life, one for my Koi pond equipment, one for a shed. The first turned out fantastic, the second was decidedly unawesome and I could never understand why. General the second thing I build turns out much better than the first.
Now I know why, Thanks Mr. Concretevol
Concretevol: #202 “I think you have to nominate yourself….I hadn’t done so until now because I thought it went without saying from my previous posts.”
Thank you for that insight. dt
gts109: #213 “Was there a gay marriage argument from comment 45 to comment 180? Because this concrete thread, which appears to be an earnest paean to concrete written by a concrete salesman, has over 200 comments.”
Once we get the lowdown on how concrete wants inheritance rights for rebar or its replacement we’ll get the commentary on whether concrete and rebar should have such rights. Not there yet.
Either way, I’m still sorry that you survived it.
Love,
Simon
P.S. Welcome home.
P.P.S. First DocJay and now BM. As Rev Wright always says, Ricochet’s chickens are coming home to roost.
No.
I’ve never been a grano worker, but concrete seems to have formed (boom boom) a part of the job wherever I’ve been.
In the Pilbara, we used high volume ice machines, chemical retarders (which can affect strength, but we were only shooting for 40MPa for house slabs and driveways) and midnight pours to combat 3 months of plus 100 degree F days. It seemed that however we planned a project, the concrete work was always in the middle of summer.
An unexpected week of 20-30F in Cobar had the opposite effect, when we couldn’t get the cure into the new slab for the SAG Mill motor. Had to set up two huge gas space heaters inside a tent.
And in Carnarvon, we had all 3 of your deadly issues – heat, wind and low humidity, plus a highly saline environment (ocean and saltfield). We used thick top covers to keep the salt away from the reo (and some SS reo), 50Mpa concrete with very select aggregates and extensive vibration, and loving care of the surface during set and cure – and I had a great contractor, a bloke (now sadly deceased) who you would have loved, Concretevol. He could come up with a successful plan for pouring concrete anywhere, and a diamond geezer to boot.
Oh, and the question I was going to ask before I got all caught up in reminiscing…
Is ultra-hard Anvil-Top concrete still used? We laid dozer and shovel tracks in workshops, pretty successfully, but I don’t see it around any more. It used a stainless fibre all mixed up in the aggregate (which was murder on your hands if you had no gloves), like some Shotcrete does.
I’m thinking it became redundant when high strength concretes became so common and cheap?
That’s the thing isn’t it? The tough jobs that are such a challenge end up being the one’s you remember. I can’t tell you anything specific about a 5000 sqft restaurant slab but can (and have) go on and on about a 70,ooo single pour slab inside of a liquid natural gas tank. We recently completed a school in South Carolina, that only had a sand dune separating it from the ocean. Just the sand itself can cause logistical issues you don’t dream of elsewhere, like using a dozer to pull concrete trucks away from the pump etc… Protecting from wind is tough, besides the shrinkage and evaporation problems you also may have to battle a nice layer of dust. Nothing like pouring a slab of grey concrete and turning around to see it has changed colors to brown. lol
BASF still makes it yes. I think that is applied as a separate layer on top of the existing slab correct? High strength concretes aren’t really what has made that product less common but dry shake hardeners and trap rock have. Products such as masterplate, masterchron, Eucoplate, etc… are applied during the installation of the slab and result in a similar impact resistant and durable surface. It only makes sense to use something like Anvil-Top to recondition an existing slab I would guess.
Tony, you should win some sort of prize. You appear to have had the final question for the concrete post!! Dime, tell him what he won!