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The problem with reinforced concrete (2016)

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Re: The problem with reinforced concrete (2016)

#21

Post by ajcp »

matheusmoreira wrote: post #16
brutusborn wrote: post #3

This should be an economics piece, not an environmental piece. The author states that "one of iron’s unalterable properties is that it rusts" yet further on acknowledges the existence of stainless steel. There's nothing wrong with reinforced concrete, but the incentives to produce long lasting buildings are not there. The cheapest bidder will generally win and their building will last the "design life" of the buildin…

How can I know if a building was designed to last a long time? Is it the materials, the method of construction?

Yes.

Re: The problem with reinforced concrete (2016)

#23

Post by throwawaysea »

An interesting read, albeit with information that is likely familiar to many. Given the issues surrounding concrete with greenhouse gases, recycling, and landfill contribution, it seems that timber (https://arstechnica.com/information-technology/2012/05/wood-...) may actually be a more viable alternative. We have techniques to grow it sustainably, it can be a carbon sink within a city, and it is mostly natural wood so it can decompose.

As an economics exercise, it may also be interesting to price in the cost of dismantling/disposing of construction materials into the initial construction cost. I wonder if doing so will steer materials development away from composites that are difficult to recycle towards something new.

Re: The problem with reinforced concrete (2016)

#24

Post by Jerry2 »

tonylemesmer wrote: post #19

Tangentially related. This company using graphene laced concrete to reduce the amount of cement required. And eliminating steel. New product called "Concretene". [0] https://twitter.com/Paul_Denney/status/1397132479144812544 [1] https://www.punchline-gloucester.com/articles/aanews/glouces...

> graphene

Graphene has its own set of problems. Namely, it can be toxic to humans. [1] And who knows what massive quantities of graphene in concrete will do to an environment 10-20 years after the building's construction. Even demolition with explosives will probably be problematic due to potentially massive clouds of nanoparticles it could create.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039077/

Re: The problem with reinforced concrete (2016)

#25

Post by ajcp »

I'm not sure this article does a good job of highlighting "the problem with reinforced concrete" than it does "the better attributes of material x with y over concrete". Reinforced concrete seems to do exactly what it's intended to do for the designed life of that intent, with some very well known trade-offs coupled with some brilliant strengths.

Sure, compared to other materials it might not be as: long-lasting, cheap, sustainable, but as in all things it seems one can only pick two.

Re: The problem with reinforced concrete (2016)

#26

Post by dwighttk »

idoh wrote: post #18

I don't know if it is really a problem, more like a tradeoff. Reinforced concrete costs less and enables shapes that are impossible without it, with the downside that the buildings last 50 years instead of 100+ years. The present value of a building that lasts 50 years is not that much different that the same one that lasts 100 years. With that in mind, it makes perfect sense to make an office building out of reinfor…

“This is going to last 1000 years!” … “It only lasted 50” … “I don’t know if it is really a problem…”

Re: The problem with reinforced concrete (2016)

#27

Post by XorNot »

Jerry2 wrote: post #24
tonylemesmer wrote: post #19

Tangentially related. This company using graphene laced concrete to reduce the amount of cement required. And eliminating steel. New product called "Concretene". [0] https://twitter.com/Paul_Denney/status/1397132479144812544 [1] https://www.punchline-gloucester.com/articles/aanews/glouces...

> graphene Graphene has its own set of problems. Namely, it can be toxic to humans. [1] And who knows what massive quantities of graphene in concrete will do to an environment 10-20 years after the building's construction. Even demolition with explosives will probably be problematic due to potentially massive clouds of nanoparticles it could create. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5039077/

Graphene isn't persistent though - it burns.

Re: The problem with reinforced concrete (2016)

#28

Post by rdiddly »

rsync wrote: post #12
opwieurposiu wrote: post #6

Reinforced concrete has achieved regulatory capture via the building codes. If you try to build with anything non-standard, prepare to deal with a mountain of red tape.

I don't believe you would encounter any red tape if you used hot-dipped galvanized rebar - I believe it is code-compliant everywhere in North America. It is, however, more expensive ...

Yep and even that zinc coating has a lifespan.

Re: The problem with reinforced concrete (2016)

#29

Post by wahern »

brutusborn wrote: post #3

This should be an economics piece, not an environmental piece. The author states that "one of iron’s unalterable properties is that it rusts" yet further on acknowledges the existence of stainless steel. There's nothing wrong with reinforced concrete, but the incentives to produce long lasting buildings are not there. The cheapest bidder will generally win and their building will last the "design life" of the buildin…

> The author states that "one of iron’s unalterable properties is that it rusts" yet further on acknowledges the existence of stainless

Even stainless steel rusts, just more slowly. Roughly 10-100x more slowly, judging by https://www.nrc.gov/docs/ML1124/ML112490377.pdf and https://www.mdpi.com/2076-3417/10/23/8705/pdf.

Re: The problem with reinforced concrete (2016)

#30

Post by 0xbadcafebee »

Once you know about spalling, you see it everywhere. There's a train bridge straddling a high-traffic road in Philadelphia that is crumbling year after year, and I think the freight company that owns it still hasn't done anything about it. We just have to hope there's no traffic when it eventually fails.
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