Dawn, I just wanted to patent it.
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Why was Roman concrete so durable?
41–50 of 299 posts
Re: Why was Roman concrete so durable?
#42Now onward to replacing the roads and bridges on freeways and highways with these new concrete.
Modern roads are designed to take serious abuse. 50 years of load cycling 20 ton semi at highway speeds causes mechanical damage which Roman concrete wouldn’t be effective in preventing. In ancient sites you can sometimes see the walls in high traffic areas have gotten smoothed and indented from hundreds of years worth of people gently dragging their fingertips across the surface as they walk by, tires are less genti…
I live in Montreal; many of the concrete structures in my city are crumbling and decaying due to the constant freeze/thaw temperature cycling that they're exposed to.
I wonder if the self-healing property of this new advanced concrete would help to avoid some of the cracking & flaking we're seeing in constructions from the 60s & 70s.
Re: Why was Roman concrete so durable?
#43Disappointed that this article didn't at least give a "tip of the hat" to the dogged research done by Dr. Marie Jackson, et.al., over her career at multiple universities. Here is an excellent read on this subject from 2013: https://cedar.wwu.edu/geology_facpubs/75/
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Re: Why was Roman concrete so durable?
#44Chemistry might be important, but we don't necessarily need that deep of an analysis. Romans didn't mind over-engineering with massive, inefficient structures. They didn't worry about complex/thin shapes, or any tensile elements. No rebar, no "piping" cement, etc. And they could put up with extremely long cure times. The end result is very, very dense concrete. We could probably recreate the durability of their concr…
Interestingly, the article founds out that their concrete cured quickly. Anyway, no, our usual concrete completely breaks down in a few centuries. No matter how it's structured, it does not match the durability of that concrete without ongoing maintenance.
>>A few centuries
Sounds good to me?
Although, many centuries old sound structures also sounds better to me...
Re: Why was Roman concrete so durable?
#45the article talks about evidence which has always been present in evaluations of Roman concrete which was "disregarded as merely evidence of sloppy mixing practices, or poor-quality raw materials," and this kind of thing REALLY infuriates me, as a layman. if you don't know how to make Roman concrete, don't assume anything about what you see in Roman concrete while you're trying to figure out how it was made. The mode…
That depends on the what you mean by smarter. At least some component of what we consider intelligence is cultural. Just one example is that the ability to write/draw allows you to solve problems that are impossible without it.
Being literate definitely means some faculties get less practice. Practically nobody today can recite epic poetry like the Odyssey, for example. That lack of rote memorization skill may have unexpected side-effects.
https://daily.jstor.org/how-do-we-know-that-epic-poems-were-...
Re: Why was Roman concrete so durable?
#46Tl;dr: Old “riddle solved”: Romans used volcanic ash as an ingredient New “riddle solved”: the good stuff also includes tiny lumps of calcium carbonate that self heal cracks
> the good stuff also includes tiny lumps of calcium carbonate that self heal cracks
According the article, they didn't use calcium carbonate directly. They use quicklime (Calcium oxide) which must be mixed in at very hot temperatures.
When a crack forms, that stuff melts and forms calcium carbonate that seals the crack.
Re: Why was Roman concrete so durable?
#47on the other end of the spectrum, did you know concrete can be used to demolish concrete?
dexpan is a special demolition concrete mix that, when poured into holes, expands at 18kpsi. it gets used when jackhammers and explosives cant be used, for example, in refineries and explosive atmospheres.
Re: Why was Roman concrete so durable?
#48Disappointed that this article didn't at least give a "tip of the hat" to the dogged research done by Dr. Marie Jackson, et.al., over her career at multiple universities. Here is an excellent read on this subject from 2013: https://cedar.wwu.edu/geology_facpubs/75/
Says a lot doesn't it. Marie Jackson makes it into the citations twelve times. Otherwise not mentioned by name. Academia: You thought capitalists were greedy for mere money? Come meet academics.
Agreed. But is this not an example of a fundamental attribution error? The structure and incentives of academia creates all the credit grabbing and back stabbing (IMO).
Re: Why was Roman concrete so durable?
#49Earlier quoted context omitted.
Modern roads are designed to take serious abuse. 50 years of load cycling 20 ton semi at highway speeds causes mechanical damage which Roman concrete wouldn’t be effective in preventing. In ancient sites you can sometimes see the walls in high traffic areas have gotten smoothed and indented from hundreds of years worth of people gently dragging their fingertips across the surface as they walk by, tires are less genti…
A fun exercise is to calcualte the cost of some road in a neighboorhood, and compare that to the total collected property tax of all the homes along that road.
A relative of mine who's otherwise a smart guy was lamenting rural broadband as an Obama boondoggle since it's never going to pay for itself to run fiber to all of the remote communities in our state... he didn't want to hear about the "P&L" for the road capital/maintenance costs.
Re: Why was Roman concrete so durable?
#50Earlier quoted context omitted.
Please don’t do this, it’s against the rules: https://news.ycombinator.com/newsguidelines.html Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that".
I think we can make an exception when someone essentially says "we don't need this article" without addressing its contents.
I dont know if in a minority ; I always read the comments on a post before I read the article...
I do this here and on reddit as well...
I still read the articles, but I like to grab the gist from comments first, it allows me to be able to read the article faster as I can skim and search at the same time.