Solidia Concrete uses a special binder — produced at lower temperatures — and patented curing process that uses CO2 rather than water. By adding and absorbing CO2, Solidia Concrete reaches strength in less than 24 hours unlike precast concrete made with Portland cement, which takes 28 days to reach strength. Solidia reduces the overall carbon footprint in precast concrete by 70%. In addition, the new product reduces the cement plant’s carbon emissions by up to 40%.This concrete can be made in a conventional cement kiln with the heat turned down, so it works within the existing systems of production.According to Kevin Ryan in Inc, the process subs out some of the traditionally used limestone for a synthetic version of the mineral wollastonite.
Lloyd Alter August 15, 2019
Solidia Technologies’ chemistry could make concrete almost benign.
The making of concrete is responsible for as much as 8 percent of annual CO2 emissions; we have called it the most destructive material on earth. The manufacturers know this is a problem and have been looking for ways to reduce the footprint before a serious price on carbon is slapped on it, and are evidently making some progress.
Carbon emissions come from two sources; traditionally, about half comes from the heating of the kiln, and about half from the chemical reaction that makes cement out of calcium carbonate. LafargeHolcim, the world’s largest cement company, has been trying to reduce the footprint of concrete for some time, although we previously noted that they are having some trouble selling it.
There is so far too little demand for sustainable materials,” said Jens Diebold, head of sustainability at LafargeHolcim. “I would love to see more demand from customers for it. There is limited sensitivity for carbon emissions in the construction of a building.
That may change; according to Kim Slowey at Construction Dive, LafargeHolcim is going to be selling reduced CO2 cement for the precast industry in the US. It uses technology from Solidia Technologies: The first customer will be the Wrightstown, New Jersey, plant of EP Henry, a national concrete products supplier that participated in LafargeHolcim’s and Solidia’s pilot of the product.
The product is the result of a six-year collaboration between LaFargeHolcim and Solidia and uses a special binder — produced at lower temperatures — and patented curing process that uses CO2 rather than water. By adding and absorbing CO2, Solidia Concrete reaches strength in less than 24 hours unlike precast concrete made with Portland cement, which takes 28 days to reach strength. Solidia reduces the overall carbon footprint in precast concrete by 70%. In addition, the new product reduces the cement plant’s carbon emissions by up to 40%. This concrete can be made in a conventional cement kiln with the heat turned down, so it works within the existing systems of production. According to Kevin Ryan in Inc, the process subs out some of the traditionally used limestone for a synthetic version of the mineral wollastonite.
“If I have to tell people to go buy some new equipment, a new kiln,” says CEO Tom Schuler, “no one’s going to adopt it.” Solidia’s manufacturing process can be done in existing facilities and costs about the same as–and, perhaps soon enough, less than–traditional cement-making methods.
Akshat Rathi wrote a long article for Quartz explaining a bit of the chemistry; it is fascinating stuff. “Wollastonite’s chemistry is such that it would not produce any emissions when it is made to produce cement, but it would, like normal cement, absorb some CO2 when it gets cured as concrete.” It’s being used for precast concrete because it actually gets cured in a CO2 filled room, and cures very fast so it probably needs controlled conditions.
© Housing and offices can be built out of hollow core slabs/ Thomas Moore
We don’t usually say nice things about concrete, and are downright nasty about the Concrete Masonry people and their marketing campaigns against wood construction. But if they can squeeze 70 percent of the CO2 out of precast concrete, I would have to change my tune a bit. Now if only there was a big honking carbon tax that would light a fire under the industry to actually change; otherwise the transition will take forever.
More in the LafargeHolcim press release.
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Jonathan Watts’ article Concrete: the most destructive material on Earth, Feb 25, 2019 in The Guardian:
The first paragraph is scary:
In the time it takes you to read this sentence, the global building industry will have poured more than 19,000 bathtubs of concrete. By the time you are halfway through this article, the volume would fill the Albert Hall and spill out into Hyde Park. In a day it would be almost the size of China’s Three Gorges Dam. In a single year, there is enough to patio over every hill, dale, nook and cranny in England.
It gets worse. We are complaining a lot about plastic, but there are only 8 billion tonnes of it since it was invented; that much concrete is made every two years. We have often complained here about the Carbon Dioxide emitted by concrete, but Watts covers all the ancillary issues that don’t get noticed as much.
There is silicosis from breathing concrete dust.
Wikipedia/ Illegal sand mining in India/CC BY 2.0
There is the sand mining that is “catastrophic – destroying so many of the world’s beaches and river courses that this form of mining is now increasingly run by organised crime gangs and associated with murderous violence.”
But a very interesting byproduct of concrete is how it affects politics.
The politics of concrete are less divisive, but more corrosive. The main problem here is inertia. Once this material binds politicians, bureaucrats and construction companies, the resulting nexus is almost impossible to budge. Party leaders need the donations and kickbacks from building firms to get elected, state planners need more projects to maintain economic growth, and construction bosses need more contracts to keep money rolling in, staff employed and political influence high.
© Guillaume Lavallée/AFP/Getty Images
Watts goes on to talk about Japan, but one need look no farther than Canada, where the government is consumed right now with the SNC-Lavalin scandal, in which there are questions of whether Prime Minister Trudeau tried to protect the nation’s largest international pourer of concrete. It could bring down the government.
Watts concludes with a quote from Phil Purnell, a professor of materials and structures at Leeds University, who makes a case for concrete: “The raw materials are virtually limitless and it will be in demand for as long as we build roads, bridges and anything else that needs a foundation.”
But the raw materials are not limitless; we are running out of sand and fresh water. We have to rethink our need for more concrete roads and more underground parking garages and more tall concrete buildings. We have to stop using so much of the stuff.
