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/diy/ - Do It Yourself



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Writing a book. It's fiction, takes place in a world where usable metals are extremely difficult to come by. Iron exists, but there's very little of it and you have to refine the shit out of it to get anything remotely usable.

What's an alternative to metallic or fiberglass rebar that could be produced in a pre-industrial society?
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>>1329029
Bamboo perhaps? It has been studied as an alternative, only thing holding it back is complexity to prepare as compared to steel rebar AFAIR
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Graphene.
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>>1329029
The bones of jews.
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>>1329029
The Romans managed without reinforcement, it is not really needed, it just allows you to use much less concrete and gives you some tensile strength.
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>>1329074
this, even constructing underpasses, usually the decorative concrete on the outside has no rebar and is just cast right on with wooden forms
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>>1329052
That might work. Thank you.
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>>1329074
>it is not really needed
>earthquake happens
>your cement buildings are now rubble
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>>1329128
still not needed, rebar and the like allows you to use much less concrete for the same strength, if you thicken the wall accordingly all is well.

Also you are making assumptions about the seismic activity of OPs fictitious world.
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>>1329074
>it is not really needed
you are a massive retard
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>>1329130
>still not needed
>rebar and the like allows you to use much less concrete for the same strength
that's exactly why it's needed to build big/tall or under big stress things
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> OP asks for a plausible alternative to rebar for use in a fictional environment where steel is not viable
> faggots argue about the need for rebar, completely ignoring the presumption that OP presents.

I fucking hate all of you cunts, you are the reason we can't have nice things.
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>>1329142
it was answered in 1st reply you retard and OP went with it
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>>1329052
Now if only I could find some real-world examples of it being done properly instead of the billion papers and slideshows put together by students all hypothesizing about how much greener bamboo is than steel and how it would totally work with no drawbacks whatsoever.

Closest I've come across was a video by some Australian dude showing some pictures of some Vietnamese guys using what looks like untreated bamboo to reinforce a concrete floor, but his take on that is that they're just being cheap and the guy who's having it built doesn't intend to stick around long enough for any problems to become evident.
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>>1329029
Cement/concrete doesn't need reinforcement, if you have the correct recipe to make it. Most importantly, using volcanic ash instead of wood ash.
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>>1329144
For those of you who actually know something about it: Is badly reinforced concrete worse than reinforced concrete?
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>>1329144
>that pic

I was just about to type up a whole thing about how I think using something like bamboo in concrete is probably a bad idea due to how it changes over time.
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>>1329145
>posts a building made of bricks
also wtf did that building get its arches bricked up or they just have brick arches worked into solid walls?
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>>1329145
Roman cement isn't magic, dude. The memes aren't real.
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>>1329146
>Is badly reinforced concrete worse than reinforced concrete?

Yes, because it means the concrete will start to crack up. That's the reason new bridge construction normally uses stainless steel rebar instead of steel.

>>1329149
>never heard of the oldest concrete building in the world

The dome on that thing is the largest unreinforced concrete dome in the world. Read up on the Pantheon.

>>1329150
I'm not sure what you are trying to say.
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>>1329148
All the information I've found points to a need for the bamboo to be both dried, coated with a waterproofing agent (maybe some kind of tar?), and ideally further shaped or cut to give it more surface area.

Correction for >>1329146:

>Is badly reinforced concrete worse than UN-reinforced concrete?
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>>1329145
>>1329154
>they built a hollow building without reinforcement
>whoa so impressive
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>>1329154
>muh big dome
they had to build it a dome so it doesn't break under it's own weight you faggot
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>>1329159
>>1329157
The ignorance, presented in these posts, is quite impressive.
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>>1329162
you are an idiot
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>>1329142
He asked about pre-industrial reinforcement, which was no reinforcement.

>>1329150
There is nothing special about their concrete, their techniques were just forgotten and only recently figured out. We have just in the past decade or two started to build concrete structures which could conceivably last as long as the Pantheon dome or the Colosseum.

>>1329154
>largest unreinforced concrete dome in the world
It is the largest freestanding concrete dome, with or without reinforcement, or has that changed in the last few years?

>stainless steel rebar instead of steel.
They use stainless because it does not react with the concrete, steel and concrete do not get along with each other, most all rebar is either stainless or coated these days. Plain steel rebar is not badly reinforced, it just has a life span of around 100 years, stainless gives you another hundred or more depending on the alloy used.

>>1329155
>>Is badly reinforced concrete worse than UN-reinforced concrete?
It is worse.
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>>1329162
No you are the one who is retarded
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>>1329029
Use Roman mortar, forget the rebar. Shit's still holding after thousands of years.
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>>1329154
>Yes, because it means the concrete will start to crack up
steel doesn't eliminate cracking. only prestressed concrete is uncracked
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>>1329074
why would someone lie on the internet?
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>>1329173
Then you could say that off-center rebar that is too close to the surface is badly reinforced.
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>>1329029
Why not use petrified wood instead of steel rebar?
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>>1329166
No, YOU'RE are a idiot.
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>>1329455
Isn't that basically stone?

Assuming you could even get it in the right shapes, would it actually add sufficient tensile strength?
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Wait, I just had an idea.

Bone. Would bone work? Because it'd be pretty badass if you could say that Warlord X built his fortress from the bones of the dragon he killed in single combat.
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>>1329029
Google is your friend. Considering the limitations placed on your fictional world, I suggest using natural basalt fibers as a substitute. The link explains it, as well as using bamboo. There are others available. Google it.
http://www.architectmagazine.com/technology/two-natural-rebar-alternatives-for-concrete_o
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>>1329572
If your audience is ok with mythical creatures I suspect they will be ok with bone used in place of rebar, even if it would not last to long in the real world. The dragon bone could also have some properties which make it good for the situation, forging with bone/tooth is not unheard of in fantasy/mythology, so why not. I say take take the artistic license, have them forge dragon bone in a sulfur flame and have fun with it.
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>>1329029
First off you should look into avoiding rebar. Ceramics and concrete are excellent for compressive stresses but not so good for stretching, that is partly where rebar comes in. Pyramids were made without need for rebar. And they still stand today.

>What's an alternative to metallic or fiberglass rebar that could be produced in a pre-industrial society?

If you absolutely need rebar there are alternatives in the form of minerals. Basalt is one that is in use today. You can process these using ancient technology but the problem is that this relies on modern knowledge. it could be argues that prolonged stone age would have arrives at that if you don't mind stretching things a little (no pun).

Asbestos is perhaps a possibility and is, strictly speaking, not glass. This is a naturally occurring mineral that might be available in your fictional world.
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>>1329572
bones have a way of turning into rocks (fossils) when left alone forever and ever.
They might have good tensile properties when fresh, but I don't think that would remain true after a hundred years.
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>>1329173
I dont even use Ss rods anymore i go fiberglass rods
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>>1329029
Not exactly rebar, but people been using wool, straw and similar fibrous meterials for reinforcement since the dawn of ages

>>1329130
>rebar and the like allows you to use much less concrete for the same strength, if you thicken the wall accordingly all is well
It's not about the strength but the shape. Without reinforcement you have to build in a way to ensure every part of the structure only bears compression forces and never tensile. So everything concrete becomes either pure vertical structures or fuckhuge domes or cones.
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Hemp?
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>>1329099

But that is still tied in to the structural stuff to some degree.
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>>1330326
>op inadvertantly realises he's just written the novella version of up in smoke
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>>1329173
>stainless steel rebar
nobody uses this

for some reason people think stainless steel = iron that does not rust
IRL, stainless steel = iron that does not rust + weaker and falls apart more easily
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>>1330551
I've tried it in the salt industry. Didn't pan out.

I went with fiberglass rods and it seems to hold up.

You are right, Ss is a coating.
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>>1329157
Show us what you've buit you cuck.
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>>1330555
Stainless steel is not a coating, chromium is part of the alloy which results in the outer surface being coated in chromium oxide which resists further corrosion. Just like the layer of aluminum oxide on the surface of aluminium.

Stainless will still corrode, just much, much slower compared to non-stainless alloys, the rate depends on the amount of chromium used.

This is in contrast to galvinised, electro-plated, platidiped, enamel, or powder coated steel which genuinely are coatings which will be destroyed if further machining is applied to the workpiece.

Stainless steel is, generally, harder than other common steel alloys, but has a lower tensile strength and shock resistance. The exception to this rule being alloys like the cobalt-steel used in tooling and ultra-high carbon steel which is very hard, but also brittle.
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Rammed earth and hardwood proved to be good construction materials.

Pic related this is a 1850's building in germany
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>>1329073
I thought I was still on /pol/
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>>1329029
Fish bones. Write in a species of fish with with stout rib bones. Make them like catfish, easy to farm, and fast growing. Fish farm could also be a good place to dispose of a body, should the plot require it.
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>>1330274
Gee, it’s almost like you’re describing exactly what ancient Roman architecture looks like...
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>>1330136
Thats not how fossils work
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I think most historic buildings were not poured, but rocks or Brock with think mortar. I think construction techniques were used took this into account, like flying buttresses.
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>>1330589
You're right.

Scratch it and it rusts much, much faster. In concrete it's junk for salt applications. May as well be a plating over carbon steel. I watch that shit get eaten through in weeks. We tried it in concrete it doesn't hold up to brine. Fiberglass works but you don't get the tensile strength but they are getting close.
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>>1331247
Right, almost like they built that way for a reason and not just because they fancied the looks
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>>1329173
>There is nothing special about their concrete, their techniques were just forgotten and only recently figured out. We have just in the past decade or two started to build concrete structures which could conceivably last as long as the Pantheon dome or the Colosseum.

Source?
This is fascination and my desire to know more intensifies.




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