DoomsdaysCW[Thread] Let's talk about #concrete! The manufacture of #PortlandCement is a HUGE source of carbon pollution and #GlobalWarming. What can we do? Look for mixes with a lower carbon footprint. And also, perhaps go back to ancient recipes! #RomanConcrete, if it were made today, wouldn't have a lower carbon output (and it might be slightly higher), but it LASTS! FOR CENTURIES! Let's take a look at the problem... And some possible solutions!
The Road to #LowCarbon #Concrete
For thousands of years, humanity has had a love affair with cement and concrete. But now, industry groups and researchers are seeking solutions to the huge amounts of carbon dioxide that cement-making generates.
M. Mitchell Waldrop, November 16, 2022
Excerpt: " To tackle the other 60 percent of cement emissions — the CO2 that’s released on the right-hand side of the calcination reaction — the industry is beginning to revive some old alternatives for cement’s raw materials.
"Simply by adding some powdered, unbaked limestone to its final product, for example, a kiln’s carbon footprint can be reduced as much as 10 percent. (Limestone alone is relatively inert but will help Portland cement harden when it’s mixed with water.) This Portland-limestone cement is already commonly used in Europe and is now taking off in the United States. 'We’re seeing regions of the country where Portland-limestone cements are the predominant material and we’re hearing individual plants say that they’re only going to produce this type from now on,' Bohan says.
"Kiln operators are also taking a fresh look at replacing some of their limestone-based cement with mineral-rich industrial waste products. One commonly used example is blast-furnace slag from steel mills, which is rich in calcium and hardens like standard cement when it’s mixed with water. Another is fly ash from coal-fired power plants, which doesn’t harden on its own, but does when it’s mixed with water and standard cement. Either way, the resulting cement yields concrete that is at least as strong and durable as the standard variety, if somewhat more abrasive and slower to cure, while potentially trimming emissions by another 15 or even 20 percent.
"Granted, there was a lot of carbon dioxide emitted during the original creation of these wastes. But using them in cement doesn’t produce any new carbon. And two-plus centuries of industrialization have left a substantial backlog of slag and ash, even if we eventually phase out coal entirely. 'It’s a win-win. If you have the waste, then replacing your clinker with it is cheaper than producing new clinker,' says Andrew. Indeed, this technique is already widely used in fast-growing countries like Brazil and China, which are producing mountains of slag and ash as they build up their industries. "
https://getpocket.com/explore/item/the-road-to-low-carbon-concrete?utm_source=firefox-newtab-en-us
#Cement #Buildings #Infrastructure #PortlandCement #CarbonFootprint
🌼 Dagnabbit, Pascaline! 🌼