RE: Environmental Impacts - Concrete
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I've read all the other comments on your post, as well as your post. My question to you was why is the water use at the point of mixing a problem in this scenario?
Every 100-pound bag of conventional cement requires 5.2-gallons of water to mix. The annual water amount needed to create concrete is equivalent to the consumption of water by 145-million people.
However, upon doing some digging, I found that OPC requires water as part of the chemical reaction that makes concrete...concrete...
Tricalcium silicate + Water--->Calcium silicate hydrate+Calcium hydroxide + heat
Chemically:
2 Ca3SiO5 + 7 H2O ---> 3 CaO.2SiO2.4H2O + 3 Ca(OH)2 + 173.6kJ**
If this is the case, water is required to cause a chemical reaction binding the tricalcium silicate.
However, I'm glad you mentioned Solidia:
“Solidia Cement™ is a non-hydraulic cement composed primarily of low-lime-containing calcium silicate phases, such as wollastonite / pseudowollastonite (CaO•SiO2), and rankinite (3CaO•2SiO2). This contrasts with the high-lime alite (3CaO•SiO2) and belite (2CaO•SiO2) phases that comprise OPC. The setting and hardening characteristics of Solidia Cement are derived from a reaction between CO2 and the calcium silicates. During the carbonation process, calcite (CaCO3) and silica (SiO2) form and are responsible for the strength development in concrete.”
https://assets.ctfassets.net/jv4d7wct8mc0/5DwEAeEYqsFAYA9UC53EF7/4f8b7566221a8d9cb38f970867003226/Solidia_Science_Backgrounder_11.21.19__5_.pdf
The pdf says there is a liquid solution that is used; however, based on the chemistry, no water is used in the chemical reactions; therefore, you can make concrete without water.
I like that you brought this to my attention. It made me go down a rabbit hole. My impression had always been that the water used in making concrete simply evaporated, therefore the use of water was not an issue. I don't have a problem with heat sources creating CO2. I know that in some cases, the product used to create the CO2 in the first place could have been pulled from the air, like renewable natural gas. When natural gas burns, you get water vapor and CO2. The world recycles itself :)
Thanks for stopping by @bobthebuilder2! You can certainly create cement and concrete now without the use of water. The current problem is that the processes used to create concrete have been standard for so long that it will take some time to vet the new processes. The industry will slowly transition from the traditional Portland Cement and concrete to move away from water use.
If you enjoy that kind of detail, I'd be happy to provide them in my later posts. I was concerned about writing an article that was too long.
To directly answer your question, the concern isn't the water used for that particular scenario. Still, it becomes a problem if you consider the amount of water needed for the billions of tons of concrete we produce annually across the globe. Society will continue to expand, and water consumption during this process will lead to competition between the industry and population use.
My grandfather once told me not to complain about a problem unless I had a solution to propose. While I don't always do this, I have found it to be one of the most profound bits of advice I've ever been given. In your post, you've done that-mentioned a problem and provided a potential solution. I enjoy seeing that kind of detail because I have trained myself to think of molecules and elements moving in harmony. I work in the natural gas industry and am amazed at the dance that carbon, hydrogen, and oxygen play to give us comfort.
What an interesting reply. My father never told me that saying, but my military and civilian training certainly did. I work in the nuclear power production industry. I specialized in water chemistry and radiation protection, but I'm now working as a radiation engineer.
I enjoy the detail of presenting a problem with a solution as well. Honestly, there's no better way to go. From a project management standpoint, you'll rarely be denied funding with this approach. The second best option is to present the problem while seeking a solution. I've seen just as good resolutions coming from that position as well.
I never ceased to get amazed when I write these STEM articles. I'm all done writing about conventional, experimental, and theoretical power production. My next stem article will probably be on botanical power production or varying obscure nuclear power technologies.
I have to switch out topics now and again though to avoid getting stale in the presentation.
I guess I'll have to look at your old articles to see if you talk about thorium based reactors vs the conventional nuclear reactors. Perhaps you could write about how renewables like solar and wind are destroying the environment they are supposedly saving... :) Saw a TEDx talk on that not long ago-it was a push for nuclear-something I'm a fan of, and it makes sense...Looking forward to see what you write next.
I don't think I've gotten to Thorium yet, but I have the material available. However, I can certainly finish it after my next post on scientific victims. It would be my pleasure.
By the way, I just saw an article yesterday and thought about you because of this article on concrete...
https://www.smithsonianmag.com/innovation/combat-climate-change-researchers-want-to-pull-carbon-dioxide-from-ocean-and-turn-it-into-rock-180977903/#:~:text=Running%20seawater%20through%20an%20ocean,limestone%20on%20a%20grand%20scale&text=All%20of%20this%20excess%20carbon,are%20sensitive%20to%20the%20change.