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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
And now for a musical interlude:
The man on our Australian $100 bill, John Monash, is among many other accomplishments, all of them of interest to Ricochet readers, the introducer of ferro-concrete to the Southern Continent. This was before the First World War, in which he earned the greater part of his fame.
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. Really unbelievable. There’s no accounting for taste.
Two reasons: 1. We didn’t realize how fascinating concrete really is, and 2. Sock Puppet Fluff
Nevil Shute’s great novel, Most Secret, has a concrete engineer as its hero. The author was in unconventional weapons development during WW2 and was not allowed to publish Most Secret till the war was over.
Concrete also figures prominently in the recent movie Locke. (The title character is a concrete engineer/specialist.)
There are two kinds of concrete.
What are they?
What kind of stout is in that pint?
At least they allowed him to publish Pied Piper during WWII. Other Shute novels involving engineers include No Highway in the Sky and The Trustee from the Toolroom.
Seawriter
Hey Jim,
I am pretty certain that they use shotcrete or gunite on those things like in pool construction. There will be a wire frame or possibly a rebar grid that is covered by spraying a cement/sand/water mixture on it. It’s more like a stucco in some ways than concrete although it is a cementuous material. Once sprayed on it can be shaped and formed by hand to form the curves of the skate park.
I don’t know if you only meant what is special in the skate park construction but those hot and dry areas out west definitely pose special problems. Many times on slabs for instance you may need to build wind breaks along the edge of freshly poured slab….use evaporation inhibitors that are sprayed on the concrete’s surface when poured, or use misters to lightly spray the concrete just to keep the surface from drying too quickly causing shrinkage cracking.
Hey Jim,
I am pretty certain that they use shotcrete or gunite on those things like in pool construction. There will be a wire frame or possibly a rebar grid that is covered by spraying a cement/sand/water mixture on it. It’s more like a stucco in some ways than concrete although it is a cementuous material. Once sprayed on it can be shaped and formed by hand to form the curves of the skate park.
I don’t know if you only meant what is special in the skate park construction but those hot and dry areas out west definitely pose special problems. Many times on slabs for instance you may need to build wind breaks along the edge of freshly poured slab….use evaporation inhibitors that are sprayed on the concrete’s surface when poured, or use misters to lightly spray the concrete just to keep the surface from drying too quickly causing shrinkage cracking.
This may be the greatest song ever recorded!!!!
Although the question is about 100 years too late for this:
how would you patch a hole in a concrete tanker?
Seawriter
Excuse me but I am NOT a “concrete salesman”. Keep slandering me and I will have Dime fit you with some special concrete shoes he is trying to get someone fitted in! lol I am a lower species, I am a concrete Contractor. I don’t sell it I buy it! :)
I was trying to figure that out…..I think it may have been an Old No. 38 Stout I had on my birthday!
Concrete we poured and inferior concrete.
Is that the S.S. Peralta? I was curious and looked up some info about those ships. Apparently the San Francisco shipbuilding company built some concrete oil tankers. Her sister ship is the S.S. San Pasqual that was run aground off Cuba. During the Cuban revolution Che Guavere used it as a prison for captured soldiers and now it is a 10 room hotel accessible by boat.
Sorry if someone’s already pointed this out, but I’ve seen a video of what was essentially a 3D printer printing a concrete building.
Boy moose, you are no doubt looking for “cracked, or going to crack.” I have heard that a lot and probably said it too. My guess is concretevol knew where you were headed.
If Jimmy Hoffa was really buried in concrete and they actually find him would his body be preserved hermetically or if not could they put in plaster and make a cast like they did with those guys in Pompeii ?
Concretevol,
I am blaming this post for Boymoose coming back to Ricochet. He saw the title and thought it was about sex.
Concrete printer
It is the SS Selma, built in WWI as part of a non-strategic materials effort to build cargo ships. They finished five or six concrete vessels, and a whole slew of wooden ones. Almost all were scrapped after the war, but a shipping company bought one of the concrete tankers and christened it Selma.
Within a few years it hit a dock hard on the Gulf Coast of Florida, knocking a hole in the hull. From there they ran to Galveston, to get it patched, but none of the dockyards there knew how to fix it. So the owners pulled the pumps they were renting and abandoned it. To get it out of the shipyard and shipping lanes the Coast Guard towed it off Pelican Island and let it beach there. Concrete being concrete (as you know) it is still there.
Seawriter
Big ConCon,
Just say the word I will give gts109 the Forever Sport ConvolsTM.
Yes, it was just a little disappointing to see him back in action, wasn’t it?
Not as disappointing as the dime is continuously BUT still….
Hopefully fixed it to show, it’s fascinating.
Since it was mentioned in the OP. The contest has begun. Feel free to donate to these worthy causes.
This should fix it.
There is a great dive bar in Charleston called the Tattooed Moose! (not sure how this is relevant but there it is)
I was thinking that it must be of the coast of Texas since you posted it but didn’t come up with the name. Well played sir! Doesn’t seem like that would have been that difficult, there are a lot of hydraulic cement plugs now…not sure about back then though.