Survivorship bias? The only Roman Concrete we see today is the stuff that has lasted.
How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
181–190 of 236 posts
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#182Earlier quoted context omitted.
I forgot another important reason why Portland cement is preferred over lime these days. Lime takes a while to set (a few days?), cement sets faster.
Cement will still take many days to reach full cure time (measured in increasing PSI ratings) https://www.ce.memphis.edu/1101/notes/concrete/section_3_pro...
But it will be set enough to keep laying bricks tomorrow. Lime on the other hand takes a bit more thought. It is doubly true if the weather is cold
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#183Earlier quoted context omitted.
> Stainless steel costs much more, but total project cost goes up less than 10%. I think people are often surprised how little materials cost affects the total cost of a job. I'm having this argument at work, where I want some more expensive cabling installed in a bunch of offices across Scotland so it doesn't need to be done again in another ten year's time, but "that stuff is so expensive, do we really need it?" is…
In general, in the UK, labour costs dominate. How do people not understand that?! This is what's interesting with AI pricing at the moment - it has gone from "a fraction of the equivalent labour cost" and so people have tried to cut staff, and is moving to "on par with labour cost" and all the calculations change.
Not just the UK, labor is usually the dominant cost of anything.
Our house flooded about half a foot a year or two ago. I had to replace all the baseboards. The damage was assessed at $40k. I tried to contact contractors to do the work, but the job was so insignificant compared to other jobs in the area, and we were in the middle of getting our house raised, that it was taking forever.
Including tools I did not have prior, material costs ran about $5k - $7k. I did the work around my job and other obligations, so about one day a week for a couple of months. If I were to honestly guess, it probably took me about two weeks. And that's measuring, cutting, installing, caulking, and painting. And there were some inefficiencies in my process.
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#184Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#185Earlier quoted context omitted.
Like the plate of food on the grass for the bees at the barbecue
Wait, does this actually work?
Just wish I could claim credit. Decoy plate is essential.
And since nobody complained it sounds wasteful, I suppose it should be able to be just scraps.
May your next camping trip or picnic be wasp free!
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#186For those not familiar, the secret ingredients are to do with the Lime Cycle [1]: 1) Quicklime/Slakedlime (Calcium Oxide, CaO) 2) Lime (Calcium Hydroxide, CaOH2) 3) Limestone (Calcium Carbonate, CaCO3) To keep it simple, typically you start with Quicklime (CaO) and after construction you end up with some mix of all three and after hundreds of years, the masonry transitions to mostly Limestone with microscopic traces…
>Fun fact! Lime putty is anti-mold even in humid conditions because upon exposure to moisture, CaOH2 + H20 becomes too basic for mold to grow on. Can we use this instead of grout in the bathroom somehow?
In India, people have used lime for all sorts of things in houses, including grout in places. It requires yearly maintenance.
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#187For those not familiar, the secret ingredients are to do with the Lime Cycle [1]: 1) Quicklime/Slakedlime (Calcium Oxide, CaO) 2) Lime (Calcium Hydroxide, CaOH2) 3) Limestone (Calcium Carbonate, CaCO3) To keep it simple, typically you start with Quicklime (CaO) and after construction you end up with some mix of all three and after hundreds of years, the masonry transitions to mostly Limestone with microscopic traces…
> Lime is more breathable, workable and sustainable. The only thing is, it requires maintainance
What sort of maintenance does it need?
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#188Yet carbonation is not universally helpful
Nothing is universally helpful in the most extreme hypothetical.
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#189Earlier quoted context omitted.
right, but lime will be washed away by the water if no waterproof layer is added
It is not lime as in the fruit, it is lime as in the material (CaOH2). Lime the material is the binding agent in lime plasters. It is not likely to get washed away.
caoh2 is water soluble (slightly). the question was about anti-mold properties and it is commonly used for these properties in paint for example in cellars but it will lose these properties when too wet. so it's not used in bathrooms.
Re: How Has Roman Concrete Lasted for Millennia? 1,900-Year-Old Latrine Offers Clues
#190Earlier quoted context omitted.
The same is said for why we don't build classical buildings anymore and trend towards more featureless stuff... and it's also mostly bullshit with plenty of counterexamples. Truth is it's often just a bit cheaper so we trend that way under capitalism, we change styles faster and have come to subconsciously accept shorter lifespans and the kind of things you can build more practical for cars, large overhangs, etc
But it's also true that modern world changes much faster than in the antiquity. If you built a church, a market, and a few utility buildings like tavern and blacksmith in 500BC you could rest assured they'd still remain used in 1000 years practically unchanged unless the structure or wider economy collapsed. Meanwhile "office building, shopping mall, nightclub, school" all varied highly in popularity within last 50 y…
Well also building cheaper makes converting such structures to other uses more costly too.
You can't simply start notching steel and adding more features and beams without a complicated engineering review because those beam were so carefully designed as to just barely hold up under their original plan.
You can't simply add a second story to a mall or walmart or modern school, none of its main structural pillars or beams could hold it. But with an overbuilt structure from 500+ years ago you likely could add another floor or two with minimal improvements to the base structure.