Image Source: Pixabay
We could take millions of steps on something during our lifetime and not know even what it is.
It wasn't until earlier this year that I found out what concrete is and why it doesn't reabsorb water after it's dry. Think about it, many things that have dried out reabsorb water like pasta, sponges and wood. Why then does concrete not become soggy when it rains? The answer lies below in this photograph of concrete which shows chemical reactions with water:
Image Source: Maria Amenta Wikimedia
Concrete is made by combining cement, water, and aggregates such as sand and/or gravel.
When mixed together, this makes a slurry which has the consistency of thick cake batter. The most common type of concrete is made from Portland cement which was developed from natural cements made in Britain beginning in the middle of the 18th century. By burning limestone and clay together at very high temperatures, you get Portland cement. But what specific compounds are contained in Portland cement? Tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite and gypsum are in it.
When you add water to the cement and aggregates, various chemical reactions occur which create a hard matrix that binds all the materials together. When these chemical reactions are happening, it’s better to think of the concrete as curing instead of drying out. So the term drying out doesn't exactly apply to concrete. But what exactly is going on in the concrete?
When water is added, each of the compounds undergoes hydration and contributes to the final form. Only the calcium silicates contribute to strength. Tricalcium silicate is responsible for most of the early strength, in the first seven days. Dicalcium silicate, which reacts more slowly, contributes to the strength at later times.
These chemical reactions form calcium silicate hydrate which then grow into crystalline fibers which bind to each other and quite literally, cement the entire mixture together.
Image Source: Wikimedia, Betonchik
The reason that concrete doesn’t dry out and then reabsorb water later is because water isn’t leaving the concrete at all.
It’s reacting with it and becoming part of the concrete form. Concrete continues to set and cure for months and years, increasing its strength over time. It’s a long-lived giant chemical reaction that continues on long after it has set. And our world would be very different without it. Imagine for a second: no concrete.
This video explains this process quite well:
It’s a good thing concrete doesn’t reabsorb water after it has cured. Can you imagine what a soggy bridge would be like to drive on?
If you want to learn more technical details about concrete, go here.
My article first appeared in Interesting Engineering. It has been modified, added to and rewritten.
In the next THAT'S FU#%ING SMART post, we'll discuss how wi-fi works.
ps- I'm currently experiencing digital hangovers in the form of debilitating migraines and therefore, I've placed myself on an information diet. I'm not on Steemit Chat, so if you want to reach me, the best way is through Twitter or here. My handle on Twitter is @stellabelle. I apologize to anyone who has tried to contact me via chat. I've also stopped using chat because I felt I wasn't terribly productive. I'm in a low productivity cycle, so every ounce of my energy has to be utilized efficiently.
Hi! I am a content-detection robot. This post is to help manual curators; I have NOT flagged you.
Here is similar content:
http://interestingengineering.com/why-concrete-doesnt-actually-dry-out/
Yes, cheetah, that's my original article I wrote. Thanks for your service.
I have noticed your post was flagged by R4fken, well known steemit hater.
I am for justice and I am here with all my Steem Power to help you resist his hate downvotes and let your post be visible for steem users. Upvoted!
Can @r4fken even move the bar with a (-6) rating? I doubt their downvote carries much sway.
However, your effort is applauded.
why thank you.
Hi @stellabelle
Thanks for the article, I have learnt something new today, in fact I learn something new on steemit daily.
(That is the problem with the cheetah bot, it does not read the articles, and would thus not know, that you wrote the article on a different platform before, as mentioned in your post)
Yeah, me too.... Thanks for reading. For some it might be a boring title........there's no clickbait involved at all!
as you say, concrete doesn't dry so much as crystalize. Concrete can set up just fine underwater.
really? I didn't know that....
Interesting post worth an upvote.
One other important aspect of concrete you should discuss are its strength properties. Concrete can bear incredible weight but crumbles when tension is applied to it. To solve this we place rebar inside concrete. It is such an important part of working with concrete it might as well be considered one of the ingredients :)
ah, yes, I did read that also, but haven't included it. Perhaps I should! Thanks
It's weird how dependent our modern world is on this material yet few of us every give it a second thought:)
The best part about concrete is that it's still being refined and developed as a building material, even in the 21st century. "Thirsty concrete" is a thing now, and this video is pretty crazy:
I don't know how they made that top layer of concrete porous like that, but it's pretty f#&$%ing smart if you ask me!
I've heard that the Hoover Dam is still curing and it's only getting stronger by the day. Pretty fascinating stuff. Now if they could just do that with our ROADS.
Hope you're feeling better. I usually hit my low cycle in December/January - just a crash & burn from WriMo and the holidays - and depression and...
I too have limited my time on chat because it's a life & time suck...but at the same time I almost feel like I need it to help promote my stuff. I'm just picking those battles!
Anyway... migraines... I get them too. Have you tried soaking your hands & feet in a warm tub while putting an ice pack on your neck? If you can survive being hunched over like that, it's actually helped me when I ran out of meds.
Nice job @stellabelle glad to see you venturing into a bit of science related postings!
Dear @stellabelle, here the Spanish translation of your article:
ESO ES JODIDAMENTE INTELIGENTE: ¿Qué es el Concreto?
Great article @stellabelle! Resteemed!
Thank you!
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