1margd
I used to tease a PhD engineer friend who specialized in cement and concrete (nukes) for having the most boring possible trade magazine. I've since learned that Romans had secret recipe that allowed their structures to persist all these years. Now, a new stronger cement that traps carbon. Methinks I owe my friend an apology!
This concrete can trap CO2 emissions forever
Bronte Lord | June 12, 2018
...concrete has an emissions problem. Its essential ingredient, cement, has a huge carbon footprint.
Cement is the glue that makes concrete strong, but the process of making cement requires superheating calcium carbonate, or limestone, and releases massive amounts of carbon dioxide into the atmosphere.
Cement is responsible for 7% of global man-made greenhouse emissions, making it the world's second largest industrial source of carbon dioxide, according to the International Energy Agency. Data from the United States Geological Survey -- the scientific agency of the US government -- reveals that global cement production was responsible for about 4 billion pounds of CO2 emissions in 2017 alone.
But a Canadian startup has invented a new system for making concrete that traps CO2 emissions forever and at the same time reduces the need for cement.
CarbonCure's system takes captured CO2 and injects it into concrete as it's being mixed. Once the concrete hardens, that carbon is sequestered forever. Even if the building is torn down, the carbon stays put. That's because it reacts with the concrete and becomes a mineral.
CarbonCure's system takes CO2 and injects it into concrete as it's being mixed.
"The best thing about it is the mineral itself improves the compressive strength of the concrete," Christie Gamble, the director of sustainability at CarbonCure, told CNNMoney.
"Because the CO2 actually helps to make the concrete stronger, concrete producers can still make concrete as strong as they need to but use less cement in the process."
And using less cement is how producers can really reduce emissions...
http://money.cnn.com/2018/06/12/technology/concrete-carboncure/index.html
This concrete can trap CO2 emissions forever
Bronte Lord | June 12, 2018
...concrete has an emissions problem. Its essential ingredient, cement, has a huge carbon footprint.
Cement is the glue that makes concrete strong, but the process of making cement requires superheating calcium carbonate, or limestone, and releases massive amounts of carbon dioxide into the atmosphere.
Cement is responsible for 7% of global man-made greenhouse emissions, making it the world's second largest industrial source of carbon dioxide, according to the International Energy Agency. Data from the United States Geological Survey -- the scientific agency of the US government -- reveals that global cement production was responsible for about 4 billion pounds of CO2 emissions in 2017 alone.
But a Canadian startup has invented a new system for making concrete that traps CO2 emissions forever and at the same time reduces the need for cement.
CarbonCure's system takes captured CO2 and injects it into concrete as it's being mixed. Once the concrete hardens, that carbon is sequestered forever. Even if the building is torn down, the carbon stays put. That's because it reacts with the concrete and becomes a mineral.
CarbonCure's system takes CO2 and injects it into concrete as it's being mixed.
"The best thing about it is the mineral itself improves the compressive strength of the concrete," Christie Gamble, the director of sustainability at CarbonCure, told CNNMoney.
"Because the CO2 actually helps to make the concrete stronger, concrete producers can still make concrete as strong as they need to but use less cement in the process."
And using less cement is how producers can really reduce emissions...
http://money.cnn.com/2018/06/12/technology/concrete-carboncure/index.html
22wonderY
The battle to curb our appetite for concrete
Add in the sand and gravel used in land reclamation, coastal developments and roads - and the current annual consumption rises to 40 billion tonnes.
This is twice the yearly amount of sediment carried by the world's rivers. In other words, we're using up sand faster than nature is creating it.
Options?
- In Australia, engineering firm Fibercon has developed a technology that uses recycled plastic for reinforcing concrete instead of the traditional steel mesh - this is now being used in footpaths.
Fibercon says by using 100% recycled plastic, the plastic-reinforced concrete gives a 90% reduction in CO2 compared to conventional steel mesh-reinforced concrete.
- At Exeter University, researchers are using nano-engineering technology to add graphene to concrete - making it twice as strong and four times more water-resistant than conventional concrete.
This new graphene-reinforced concrete also has huge efficiency savings, cutting the raw materials required to make concrete by some 50%.
- Another approach that could revolutionise the industry is the 3D printing of houses.
Because there's no penalty for over-designing a building, architects often err on the side of safety and buildings can contain 40% more concrete than they need.
One way of stopping this is by 3D printing buildings, creating concrete shapes directly from an architect's design.
- Canadian firm CarbonCure has developed a way of locking in more carbon by injecting liquefied CO2 into wet concrete.
Not only is the concrete stronger, the firm says it could save up to 700 million tonnes of CO2 emissions a year. So far, 100 producers have adopted the technology
Add in the sand and gravel used in land reclamation, coastal developments and roads - and the current annual consumption rises to 40 billion tonnes.
This is twice the yearly amount of sediment carried by the world's rivers. In other words, we're using up sand faster than nature is creating it.
Options?
- In Australia, engineering firm Fibercon has developed a technology that uses recycled plastic for reinforcing concrete instead of the traditional steel mesh - this is now being used in footpaths.
Fibercon says by using 100% recycled plastic, the plastic-reinforced concrete gives a 90% reduction in CO2 compared to conventional steel mesh-reinforced concrete.
- At Exeter University, researchers are using nano-engineering technology to add graphene to concrete - making it twice as strong and four times more water-resistant than conventional concrete.
This new graphene-reinforced concrete also has huge efficiency savings, cutting the raw materials required to make concrete by some 50%.
- Another approach that could revolutionise the industry is the 3D printing of houses.
Because there's no penalty for over-designing a building, architects often err on the side of safety and buildings can contain 40% more concrete than they need.
One way of stopping this is by 3D printing buildings, creating concrete shapes directly from an architect's design.
- Canadian firm CarbonCure has developed a way of locking in more carbon by injecting liquefied CO2 into wet concrete.
Not only is the concrete stronger, the firm says it could save up to 700 million tonnes of CO2 emissions a year. So far, 100 producers have adopted the technology
3margd
Nature Portfolio: "Producing the most widely used type of cement from calcium-rich silicate rocks such as basalt, instead of limestone, could reduce carbon dioxide emissions from the cement production industry by more than 80 percent, according to research in Communications Sustainability.
The switch in raw materials could be made with existing technologies, and producing Portland cement from these rocks could theoretically require less than 60 percent of the energy currently needed when using limestone."
-----------------------------------------------
Prancevic, J.P., Finke, C.E., Peterson, E. et al. Silicate-derived calcium as a pathway to low-carbon Portland cement. Commun. Sustain. 1, 78 (2026). https://doi.org/10.1038/s44458-026-00056-4
Abstract
Cement production accounts for 4.4% of global greenhouse gas emissions by releasing carbon dioxide from limestone and using an energy-intensive process. Decarbonization technologies, including lower-carbon alternative cements and carbon capture, have existed for decades but have not been adopted. Here we examine the viability of making ordinary Portland cement using carbon-free silicate rocks (like common basalt) instead of limestone. Our thermodynamic analysis shows that producing Portland cement from basalt could require less energy than traditional limestone production, highlighting the potential to simultaneously reduce cost and emissions. We identify a set of proven unit processes to produce Portland cement and supplementary cementitious materials from basalt minerals that could reduce the total energy demand by 30% with respect to conventional production, while eliminating process emissions entirely. Also, the ratios of calcium, iron, and aluminum in basalt are favorable for meeting the global demand for Portland cement, steel, and aluminum from one feedstock.
The switch in raw materials could be made with existing technologies, and producing Portland cement from these rocks could theoretically require less than 60 percent of the energy currently needed when using limestone."
-----------------------------------------------
Prancevic, J.P., Finke, C.E., Peterson, E. et al. Silicate-derived calcium as a pathway to low-carbon Portland cement. Commun. Sustain. 1, 78 (2026). https://doi.org/10.1038/s44458-026-00056-4
Abstract
Cement production accounts for 4.4% of global greenhouse gas emissions by releasing carbon dioxide from limestone and using an energy-intensive process. Decarbonization technologies, including lower-carbon alternative cements and carbon capture, have existed for decades but have not been adopted. Here we examine the viability of making ordinary Portland cement using carbon-free silicate rocks (like common basalt) instead of limestone. Our thermodynamic analysis shows that producing Portland cement from basalt could require less energy than traditional limestone production, highlighting the potential to simultaneously reduce cost and emissions. We identify a set of proven unit processes to produce Portland cement and supplementary cementitious materials from basalt minerals that could reduce the total energy demand by 30% with respect to conventional production, while eliminating process emissions entirely. Also, the ratios of calcium, iron, and aluminum in basalt are favorable for meeting the global demand for Portland cement, steel, and aluminum from one feedstock.
4reading_fox
It's the scale that's the issue. There have been various more eco-friendly concrete's proposed in the past, none have gone anywhere. If it's 1p /ton more expensive to produce at 40 billion tonnes that's a vast amount of extra cost that ends up somewhere. Likewise it's all very well making it out of food waste or whatever, but there just isn't that much raw material lying around.
5John5918
And leaving aside the issue of cement and concrete, there are reports that the world is also running out of sand for cosntruction.
Why the world is running out of sand (BBC)
Sand is a major international export, with the USA apparently being the largest exporter by a long margin (link).
Why the world is running out of sand (BBC)
Sand, however, is the most-consumed natural resource on the planet besides water. People use some 50 billion tonnes of “aggregate” – the industry term for sand and gravel, which tend to be found together – every year. That’s more than enough to blanket the entire United Kingdom. The problem lies in the type of sand we are using. Desert sand is largely useless to us. The overwhelming bulk of the sand we harvest goes to make concrete, and for that purpose, desert sand grains are the wrong shape. Eroded by wind rather than water, they are too smooth and rounded to lock together to form stable concrete. The sand we need is the more angular stuff found in the beds, banks, and floodplains of rivers, as well as in lakes and on the seashore. The demand for that material is so intense that around the world, riverbeds and beaches are being stripped bare, and farmlands and forests torn up to get at the precious grains. And in a growing number of countries, criminal gangs have moved in to the trade, spawning an often lethal black market in sand...
Sand is a major international export, with the USA apparently being the largest exporter by a long margin (link).
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