[HN Gopher] Cement's future could be a combination of carbon cap...
       ___________________________________________________________________
        
       Cement's future could be a combination of carbon capture and
       electrification
        
       Author : hannob
       Score  : 97 points
       Date   : 2023-06-15 12:02 UTC (10 hours ago)
        
 (HTM) web link (industrydecarbonization.com)
 (TXT) w3m dump (industrydecarbonization.com)
        
       | photochemsyn wrote:
       | Seawater is a source of calcium, and it looks like desalination
       | concentrate is an option for limited scale production:
       | 
       | https://www.nature.com/articles/s41545-022-00153-6
       | 
       | "Seawater desalination concentrate--a new frontier for
       | sustainable mining of valuable minerals" (2022)
       | 
       | > "The metallic elements found in the highest concentration are
       | sodium, magnesium, calcium and potassium, which have been
       | commercially extracted as the chlorides, sulfates, and carbonates
       | while magnesium has been extracted as the hydroxide."
        
       | samwillis wrote:
       | The best way to reduce carbon emission from cement would be to
       | use less of it.
       | 
       | Here in the UK, 30% of the cost of a new house build is the
       | foundations, the excavation, and then filling of a hole in the
       | ground with many tons of concrete. I find it baffling how little
       | innovation in construction has been adopted by the house building
       | industry here. Light weight timber frame construction on pile
       | foundations would massively reduce both the carbon footprint of
       | the build and the cost.
       | 
       | When I have made these arguments before, people often respond
       | that our heavy weight brick construction is better as it
       | withstands the weather more, and will last longer. But with
       | modern materials (or good old traditional maintenance) thats just
       | not true, a timber frame house can last hundreds of years.
       | 
       | Finally, it's not just the carbon emissions from cement
       | manufacturing that worries me. I live about 3 miles from a cement
       | factory, and the amount of dust that it puts out is staggering.
       | If I clean my car, within two days it's covered in a thin layer
       | of dust thats locally attributed to the factory. I can't imagine
       | thats good for our health!
        
         | londons_explore wrote:
         | There is a good argument that buildings _shouldn 't_ last so
         | long.
         | 
         | Buildings a mere 50 years ago probably have very poor
         | insulation (and hence high heating/cooling environmental +
         | monetary costs), have electrics that aren't considered safe
         | today, have plumbing probably containing lots of lead, and are
         | lacking amenities considered standard today (electrical outlet
         | next to the bed for phone charging, mixer taps, etc). Those
         | buildings probably won't resist fire for long, and probably
         | won't be suitable for heat pump heating. Sound insulation
         | probably won't be good, so you probably get woken by your
         | neighbour having sex.
         | 
         | All those things are fixable for a cost, or livable with a hit
         | to quality of life, the environment, the house owners health,
         | etc.
         | 
         | If we assume that the requirements for a home continue to
         | evolve, then we can see that something built today would be
         | unlikely well suited for use in 50 years. Considering that,
         | perhaps it's best to build something easy to disassemble and
         | rebuild 50 years from now.
        
           | mortify wrote:
           | Sound insulation in older homes is much better than in new.
           | Thicker and heavier materials are much better at absorbing or
           | reflecting sound, especially low frequency. Fire resistance
           | seems to be a wash. I've seen the aftermath of new and old
           | construction. We don't seem to have made improvements in this
           | regard, but we have made the likelihood of them starting
           | lower in all kinds of construction.
           | 
           | The opposing argument for much of their down-sides is the up-
           | front cost of building a new home has it's own environmental
           | and financial costs. Much of the down-sides to older homes
           | can be retrofitted for substantially less cost and impact
           | than a new home.
           | 
           | We could get the best of both worlds by designing homes for
           | upgrades with large conduits for wirings, easier access to
           | walls and attics, etc.
        
             | CraigJPerry wrote:
             | >> by designing homes for upgrades with large conduits for
             | wirings
             | 
             | Why isn't this more common? I've watched a few spray foam
             | installations on youtube where they just spray directly
             | over romex / wiring / cables .
        
               | brohee wrote:
               | I think this is kinda needed for air tightness, but
               | shouldn't stop anyone from running empty conduits for
               | future use...
        
               | spockz wrote:
               | Because that allows contractors to sell empty conduits at
               | a large margin. Every conduit and potential outlet is
               | charged for through the nose.
        
             | oh_sigh wrote:
             | The best apartment building I ever lived in in NYC was
             | built in the 1920s and was built "naturally fireproof",
             | where there were thick masonry walls between each unit to
             | prevent the spread of fire. I literally never heard a
             | single neighbor, anywhere, ever. Not my same-floor
             | neighbors, nor the people above or below me.
             | 
             | Compare that with newer buildings I lived in, where I would
             | be woken up at 3AM by my upstairs neighbor's cat running
             | around.
        
           | skullone wrote:
           | My house was built in 1885, timber framed. There's no rot,
           | it's been maintained, re-plumbed and re-wired a few times,
           | and new owners only need to keep with basic maintenance. It's
           | been insulated as well, utility bills are in the $90-150
           | range depending on how extreme the seasons get. The structure
           | has another century left in it, easy.
        
           | HPsquared wrote:
           | It's surely cheaper to rewire and refit, than to knock the
           | whole thing down to the foundations and start again.
        
             | londons_explore wrote:
             | Doing all those things at once, it's usually cheaper to
             | knock down and start from scratch.
             | 
             | The problem lies in a homeowner who doesn't have much spare
             | cash - so they rewire one year... and then a few years
             | later they replumb... and then a few years later they
             | replace the roof... etc.
             | 
             | Overall, they spent more, but in small increments so it
             | didn't feel like more.
             | 
             | Typically regulations allow things to be 'grandfathered' -
             | so renovating a house allows you to avoid getting
             | permission to rebuild, which may be denied.
        
               | notahacker wrote:
               | The idea that periodic replumbing and rewiring and
               | replacing roofing felt costs less overall than a complete
               | rebuild is questionable enough in terms of financial
               | cost, even more so in terms of carbon output cost.
               | 
               | Sure, the [carbon] accounting looks a little different if
               | you're having to pull out most of the load-bearing walls
               | to accommodate a change of use and underpin to build on
               | top or considering replacing old masonry with something
               | built to maximise energy efficiency. But rebuilding
               | entire houses to keep up with the latest fads in mobile
               | charge ports and mixer taps is about as good for the
               | environment as "fast fashion"!
        
               | rootusrootus wrote:
               | > Doing all those things at once, it's usually cheaper to
               | knock down and start from scratch.
               | 
               | This must be regional. In the PNW we'd never knock
               | something down for that. Stripping the drywall out and
               | redoing the plumbing/electrical/insulation is quite a lot
               | less expensive than putting up a whole new structure.
        
               | cmrdporcupine wrote:
               | Beyond finances, there's simply the nightmare of -- where
               | the hell do I live while my house is being rebuilt? We've
               | put off kitchen & main floor _renovations_ for a half
               | decade simply because we don 't want to deal with the
               | hassle, a rebuild is another thing entirely.
        
               | londons_explore wrote:
               | Many houses are naturally unused for months at a time -
               | for example between tenants if let. Between owners when
               | sold, or after the inhabitant passes away.
        
         | dubcanada wrote:
         | > Light weight timber frame construction on pile foundations
         | 
         | > But with modern materials (or good old traditional
         | maintenance) thats just not true, a timber frame house can last
         | hundreds of years.
         | 
         | I am not sure were you are reading that "timber frame house can
         | last hundreds of years" but I don't believe that is correct,
         | most timber frame houses have an estimated 30 year life span. A
         | stone/brick house can last thousands of years.
         | 
         | I do agree that a stick frame/light weight timber house is way
         | less concrete then a brick/stone house. But UK doesn't have a
         | ton of trees, so the majority of those trees are imported from
         | EU places like Belarus or Canada. Which is a bunch of gas in
         | itself.
         | 
         | Pile foundations also have tons of problems, and have a very
         | high fail rate. They don't do well with salt water, so costal
         | areas in UK will have problems, they don't do well with
         | stone/bedrock. Which UK has a ton of.
         | 
         | I believe there is tons of work to do, but I disagree that the
         | solution is stick framing and pile foundations. I think the
         | actual solution is innovation and reduction of some building
         | standards to allow innovation. It's very very difficult to even
         | experiment with building materials as every building code
         | requires X insulation and any building official will complain
         | if you have Y. So everyone just uses X.
         | 
         | ICF for example is absolute garbage, its marketed as a eco
         | friendly, green building material that's made from oil and
         | filled with a truck load of cement. How that got classified as
         | a "eco-friendly green building material" is beyond me.
         | 
         | Meanwhile things that are actually eco-friendly like hemp,
         | straw, etc all require a ton of engineering and have zero
         | standards, so everything has to be engineered. And you'll get
         | crazy looks from building officials when you ask for a review
         | of your straw timber frame house.
        
           | mauvehaus wrote:
           | Timber frames can definitely last hundreds of years. I have
           | multiple family members on my wife's side who live in houses
           | with parts dating back 100-200 years. They've been kept up
           | and more or less continuously occupied, but it's not as
           | though that meant continuously conditioned as we would think
           | of it until sometime in the 20th century.
           | 
           | Hell, you can drive through New England and see barns that
           | are 150 years old that are only starting to fall down after
           | 50 years of deferred maintenance.
           | 
           | If you keep wood dry, it'll last a good long while. Whether
           | you consider 100-200 years a long time, will of course depend
           | on perspective:
           | 
           | "In Europe, they think 100 miles is a long way. In the US,
           | they think 100 years is a long time."
           | 
           | - William the Conqueror
        
           | theluketaylor wrote:
           | I live in a ballon-framed house built in 1926. Coming up on
           | 100 years and with reasonable maintenance there is no reason
           | it won't last another 100. There are some terribly built
           | wooden houses that will just rot away, but it's not that hard
           | to do it right.
           | 
           | Wood as a building material when used properly can be
           | incredibly resilient, especially with modern mass timber
           | solutions rather than raw wood.
        
             | Dig1t wrote:
             | >with modern mass timber solutions rather than raw wood
             | 
             | Do you mean things like LSL?
             | 
             | I actually wonder what the longevity of LSL is compared to
             | raw wood. Since it's a ton of resin mixed with wood, I
             | wonder about the resin part of it.
             | 
             | It does seem much better to build with as bugs won't eat it
             | and it's perfectly straight.
        
               | theluketaylor wrote:
               | Laminated strand is certainly under the heading of mass
               | timber, but I'm referring more to cross laminated timber
               | (CLT). It still uses resin, but with much more wood it
               | doesn't suffer from the sort of rot and de-laminating
               | problems OSB has, but it's still highly engineered and
               | highly precise like LSL.
               | 
               | Laminated veneer lumber (LVL) has become common in North
               | America for beams and joists. CLT uses even larger
               | components and is even more flexible. It's just starting
               | to be used but you can build everything from a house to
               | 20 storey buildings.
        
               | robbiep wrote:
               | I know nothing about this, but do you know what the
               | environmental/recyclable potential of the resins are?
        
             | SoftTalker wrote:
             | Agree. My first house was a wood-frame bungalow built near
             | the prior turn of the century. As long as you don't get
             | termites, and maintain the roof and siding so you don't
             | have water leaking in, wood houses will last basically
             | forever, or at least on the order of 100 years.
        
             | cand0r wrote:
             | I'd like to point out that wood 100 years ago was mostly
             | old growth, which differs drastically to the lumber
             | available today.
        
               | theluketaylor wrote:
               | Modern mass timber more than corrects that problem. It
               | does a fantastic job using fast growing, new growth
               | lumber to produce highly precise parts that are factory
               | produced exactly to spec to nearly eliminate waste.
        
               | 8note wrote:
               | Highly precise lumber parts sounds like an oxymoron. The
               | standard assumption for wood is that it's only straight
               | while it's being cut. If they've invented fix for that,
               | it's not gonna be the wood that they're using that does
               | it, but some extra processing to make like a particle
               | board or something
        
               | theluketaylor wrote:
               | Modern mass timber has advanced a long way beyond cheap
               | particle board. Read up on cross laminated timber.
               | Manufactured and cut exactly to size and often requires
               | no cutting on site.
        
           | rootusrootus wrote:
           | > estimated 30 year life span
           | 
           | Did you misplace a digit? If you're only getting 30 years
           | from a wood frame house, you're _definitely_ doing something
           | wrong.
        
           | luplex wrote:
           | > I am not sure were you are reading that "timber frame house
           | can last hundreds of years" but I don't believe that is
           | correct, most timber frame houses have an estimated 30 year
           | life span. A stone/brick house can last thousands of years.
           | 
           | I have in fact lived in a timber frame house that was 400
           | years old and going strong. No idea about its history, but it
           | was rather comfortable and cozy. It wasn't particularly well
           | insulated though.
        
           | linuxandrew wrote:
           | Different climate but I lived in two poorly maintained
           | Queenslanders[1] which were a popular style of timber on
           | piles here, both 50 years old and would easily last longer.
           | One even had minor termite damage which was later treated.
           | 
           | Many people here do knock down rebuilds but most would easily
           | last longer than 30 years. Many timber houses get re-stumped
           | after a few decades and concrete piles seem to be a popular
           | choice for replacement.
           | 
           | I see a lot of poorly built homes on slabs as well which seem
           | to have a similar lifespan as the Queenslanders
           | (anecdotally).
           | 
           | 1:
           | https://en.m.wikipedia.org/wiki/Queenslander_(architecture)
        
           | vidarh wrote:
           | > I am not sure were you are reading that "timber frame house
           | can last hundreds of years" but I don't believe that is
           | correct, most timber frame houses have an estimated 30 year
           | life span. A stone/brick house can last thousands of years.
           | 
           | I grew up in a four family timber house built in the 1960's.
           | It's still standing. As are all the houses on that road which
           | were all built at the same time. We moved to a timber house
           | built around 1910. It's still standing - I walked past it
           | just last year. My grandparents lived in a development of all
           | wooden houses built in the 1950's. They're all standing.
           | 
           | Where did you get this notion they have a life span of 30
           | years? Norway has plenty of wooden houses that have stood for
           | a 100+ years, and a huge bulk of post-war construction from
           | the 50's and 60's in wood.
           | 
           | On the more extreme end, there are a number of stave churches
           | in wood dating back to the 1200's. Of course they're the
           | outlies that survived, and have certainly required
           | maintenance.
           | 
           | EDIT: Here's a list of stave churches in Norway, and
           | construction years. Some of these have been rebuilt during
           | that time, but even those that have typically have a lifetime
           | of each iteration measured in centuries, with a few
           | exceptions:
           | 
           | https://en.wikipedia.org/wiki/List_of_stave_churches_in_Norw.
           | ..
           | 
           | As a fun curiosity, here's Vang stave church, "moved" from
           | Norway to Poland in 1842, originally built in the 1200's.
           | "Moved" because most of the material ended up being discarded
           | because the builders handling the re-erection didn't quite
           | know how and found it easier to replace most of it. So the
           | current iteration is really "only ~180 years old, and might
           | have been moved and rebuilt once before, but in any case each
           | iteration survived rather a bit longer than 30 years:
           | 
           | https://en.wikipedia.org/wiki/Vang_Stave_Church
        
             | bequanna wrote:
             | 30 years is far too low. Most homes built in the US will
             | easily make it 70 years.
             | 
             | Heck, I've seen many trailer houses that are in decent
             | shape and >30 years old.
        
             | throwway120385 wrote:
             | The life span is probably more due to the lifespan of the
             | plumbing. On high-grade copper(L- or K-) you can get a
             | useful life of 50 years but PEX is only rated for 30 years,
             | and the lowest grade of copper(M-type) has a similar
             | replacement interval. The valves used in plumbing fixtures
             | also wear out and need replacement periodically. And the
             | valve housings do as well. The anode in a water heater will
             | probably only last a couple of decades. These are all
             | replaceable parts.
             | 
             | Siding is in a similar state, with many modern sidings have
             | replacement intervals in the decades, and shorter time
             | periods if you don't paint every 5-10 years.
             | 
             | If properly maintained and if parts are replaced in a
             | timely manner a house can last indefintely. My partner and
             | I own a house from 1935 that was last renovated in the
             | 1990s, and I'm starting to have to make minor plumbing
             | repairs. I think in the next 10 years or so we'll have to
             | re-pipe and re-wire. But the framing and sheathing is
             | almost all original, except for the roof deck which was
             | replaced first in the 1990's and then parts were replaced
             | when we re-roofed last year(the original roofer did not
             | know how to frame to support a rake board).
             | 
             | Everything also changes if you factor in repainting and
             | replacement of interior fixtures.
             | 
             | But still, if you maintain it and factor in all these
             | repairs and replacements your house can last for hundreds
             | of years.
        
               | CalRobert wrote:
               | For what it's worth, I have a 200 year old cottage that
               | probably has a few centuries left in it, and the plumbing
               | and wiring is all in conduits that are easily accessed.
               | Maybe we should make it easier to replace this stuff
               | without ripping the house apart?
        
         | CalRobert wrote:
         | I had a house built in Ireland and the architect was a huge
         | pain in the ass. She wanted concrete _ceilings_ ffs. In a
         | single story dwelling. She also thought it was ludicrous I
         | wasn't using concrete blocks, and anything like a pier or post
         | and beam foundation was completely out of the question.
         | 
         | The funny thing is that the houses here are pure shite so it's
         | not like this approach has been working for them. Utter,
         | abominable, crap. Ugly, too.
         | 
         | I was able to get a timber frame and wood ceilings but still
         | have a concrete foundation. The builders were so proud of it
         | being an insulated foundation (KORE) but you wouldn't even
         | _need_ that if the house were lifted off the ground, like it
         | should be.
         | 
         | I asked one forward-minded engineer about it and he said it was
         | down to people being brainwashed by "concrete built is better
         | built" ads from the 80's and centuries of complete
         | deforestation.
        
         | slothtrop wrote:
         | Cement is used in most city infrastructure, for industrial
         | builds, etc. The demand for it in the U.S. probably dwarfs the
         | UK several times over despite lumber use for houses, _and_
         | poured concrete no longer popularly used for foundations.
         | 
         | If you want to abate it, you'd need to look far beyond that
         | particular use-case in the UK. I don't see low-hanging fruit
         | here. Cement is reliable and inexpensive. There is R&D in the
         | works for eco-cement, but this appears to be in early stages.
         | 
         | It's possible to reduce emissions in its production in the
         | first place. Notwithstanding the calcium carbonate, energy
         | inputs (which are very high) could eventually not rely on
         | fossil fuels.
         | 
         | If the goal is to pursue an aggressive timeline for curbing CO2
         | emissions then probably CC & electrical will appear first.
        
         | OrvalWintermute wrote:
         | > The best way to reduce carbon emission from cement would be
         | to use less of it.
         | 
         | Disagree.
         | 
         | I think we need to return to the future through rediscovering
         | Roman Concrete [1] and making structures that can last
         | thousands of years.
         | 
         | Concrete also, can be recycled and used again.
         | 
         | Because we are in a deglaciation period currently, in general I
         | am skeptical about moving to a low CO2 environment which is not
         | normal for the earth. However, I am sensitive to the fact that
         | we must be stewards and caretakers of the earth and make the
         | best use of resources, while polluting less, and moving to a
         | more sustainable future through a grand conversion process
         | eventually.
         | 
         | [1] https://news.mit.edu/2023/roman-concrete-durability-lime-
         | cas...
        
         | pjc50 wrote:
         | How is the relative cost? Timber is historically much more
         | expensive in the UK than in the US, the major user of timber
         | construction.
        
           | samwillis wrote:
           | Correct, timber is expensive here - particularly over the
           | last 3 years - but I believe a timber frame construction is
           | still a little lower than a brick contraction in cost. SIPs
           | (structurally insulated panels) are more expensive than
           | brick, but I suspect that more to do with available expertise
           | and the need for expensive cranes. (As an aside its
           | fascinating visiting France where every house building site
           | has a crane, none do here)
           | 
           | But many timber frame houses here are still build on massive
           | concrete slabs, and that is still pouring money into the
           | ground. We need to adopt innovations like screw piles that
           | are completely concrete free.
        
             | throwway120385 wrote:
             | Having had to buck timber trusses to a second floor roof, I
             | think cranes are a wonderful invention and we should have
             | more of them.
        
         | was_a_dev wrote:
         | I know we have wet and cold climate in the UK, but it is also
         | pretty mild.
         | 
         | We could have timber framed housing, as we don't get hit by
         | natural disasters with the exception of flooding
        
         | ZeroGravitas wrote:
         | Reduction is also item number 1 in their linked factsheet:
         | 
         | https://fcarchitects.org/wp-content/uploads/2023/02/20230206...
         | 
         | > Modernize building standards to favor low-carbon materials
         | and circular use
         | 
         | > Promote low-carbon practices in industry and curricula
         | 
         | > Update building and infrastructure regulations based on
         | required performance, instead of prescriptions on material
         | conten
        
         | theluketaylor wrote:
         | For regions that don't have to worry about a frost line helical
         | screw piles and mass timber are game-changing building
         | capabilities to construct concrete free. It's even possible to
         | build carbon negative thanks to the timber locked in the
         | building. And it's way faster since you don't spend months
         | preparing a site and building forms.
         | 
         | Even frost line regions could dramatically cut their concrete
         | usage if they just focused on protecting the water lines. You
         | would lose a basement, but those are expensive per sq ft
         | anyway. Just go up another floor for less total costs.
         | 
         | Local building codes will get in the way since building
         | inspectors tend to reject things they haven't seen before (like
         | mass timber frame) and way too many places have incredibly
         | strict height restrictions.
         | 
         | It is incredible to watch helical screw piles go in. A friend
         | needed 60+ posts installed for a big fence. Would have been
         | days of digging or augering post holes down 4 ft for the frost
         | line and then mixing hundreds of bags of cement and filling the
         | holes with concrete. Instead a contractor with a small tracked
         | machine that fit through a standard gate drove every pile in
         | under an hour.
        
           | dylan604 wrote:
           | >And it's way faster since you don't spend months preparing a
           | site and building forms.
           | 
           | What size house are you building that it takes months
           | preparing a site to build foundations? Sub 2000sqft houses
           | are built to completion in 90-120 days if weather doesn't
           | delay things. It only takes a couple of weeks from clearing
           | the site, digging the trenches, lining the moisture barrier,
           | laying the rebar and forms, then pouring the cement. The
           | formulas today cure very quickly. From the day of the pour to
           | the start of framing is practically the blink of an eye
        
             | theluketaylor wrote:
             | Here in Canada it's extremely common for ground works for a
             | new subdivision to take over a year.
             | 
             | Individual houses can be done in a much shorter time, but
             | digging a basement, setting all the forms, pouring the
             | concrete, waterproofing the walls, underpinning the water
             | management, and then back filling back to grade is not a
             | quick process.
        
               | dylan604 wrote:
               | You're comparing the time it takes a developer to clear
               | the entire development to the time it takes to build a
               | single house. These are not the same thing. That's
               | comparing apples and oranges. Comparing the time for a
               | house with no basement to one with a basement is
               | comparing a granny smith to a red delicious.
        
               | theluketaylor wrote:
               | Even a single house worth of ground works is 30-60 days
               | pretty easily.
        
           | rafamvc wrote:
           | You can use helical screw piles in places with a frost line.
           | As long as the blades are below the frost line.
        
             | theluketaylor wrote:
             | Absolutely true, but you still need a plan for protecting
             | the water lines. You need some kind of underground
             | insulated structure below the frost line that can handle
             | direct dirt contact. Annoyingly concrete remains the best
             | option.
        
               | SoftTalker wrote:
               | I live in an area with freezing weather. The water pipe
               | to my house is just a PVC pipe buried below the frost
               | line, i.e. in a trench about 3 or 4 feet deep. There's no
               | concrete involved.
        
               | blake1 wrote:
               | Was recently in a fairly new construction house in a very
               | cold climate state that did not have a full basement
               | below the frost line. There was a partial 8'x8' corner
               | that sunk down to where the water line came in, but the
               | rest of the footprint was a crawl space. Losing the
               | basement does affect the style of building that is
               | economical to build on top though, mainly due to building
               | codes.
        
               | SoftTalker wrote:
               | A basement is nice to have if you live in an area with
               | tornados.
        
         | nofeelings wrote:
         | Why aren't they already doing that? If what you're saying is
         | true they would since the implication is that it's cheaper.
        
           | replygirl wrote:
           | Same reason most people don't write Rust: The talent, best
           | practices, and vendor ecosystem are less accessible. Similar
           | to Rust it's much more accessible than people _think_ though
        
       | cschmidt wrote:
       | Here's an interesting Economist article on the same subject:
       | 
       | https://www.economist.com/science-and-technology/2023/06/07/...
        
         | JumpCrisscross wrote:
         | I was just sent a _Vox_ video on the topic. Someone is running
         | a campaign.
        
       | Faaak wrote:
       | Mixing biochar with concrete actually makes it harder (or you can
       | add less cement to it), while storing CO2 (biochar is a viable
       | CO2 pit).
       | 
       | Can't link the sources because mobile, but if you're interested
       | look it up, it's really interesting. It's being certified in
       | France right now.
        
       | luis_cho wrote:
       | Why do we need more cement?
       | 
       | In my country there are 2 houses for each family, and we in a
       | housing crisis.
       | 
       | Maybe the solution can be less speculation, a social solution
       | instead of a technological one.
        
         | slothtrop wrote:
         | Even if you want to increase density, you'd need concrete to
         | achieve it. Cost of housing is inversely correlated to the rate
         | of new builds in cities, and the reason is the growth in demand
         | through immigration. Can't have your cake and eat it too: want
         | more immigration? Build more.
         | 
         | > a social solution
         | 
         | Such as what, coercing multiple families to share detached
         | homes? Would you volunteer for that? And how far do we expect
         | to push that when the demand for housing will keep growing?
        
           | drekk wrote:
           | Apartments work fine? In lower density areas simple duplexes
           | or quadplexes work fine. We don't need every single family
           | living in an isolated home with the white picket fence.
           | 
           | We have more than enough homes. There are over two dozen
           | empty homes per homeless person. It's not just an issue of
           | building more. Shelter is being treated as a speculative
           | asset and the only meaningful vehicle for building weath in
           | the middle class. Hence the need for a social solution.
        
             | slothtrop wrote:
             | > Apartments work fine?
             | 
             | You must be familiar with the monumental amount of concrete
             | these require, yes? They are more dense, but not "low-
             | carbon" by any stretch.
             | 
             | > We don't need every single family living in an isolated
             | home with the white picket fence.
             | 
             | Families can decide for themselves what suits them. It's
             | not your place to tell someone they don't "need" something.
             | You don't "need" most of your possessions. Hell you don't
             | even "need" a roof over your head, as it pertains to
             | survival.
             | 
             | And we sure don't "need" to race to the bottom and demand
             | lower qualify of life from everyone. Not for homelessness,
             | and not for building efficiency. It does not solve
             | anything. It's purpose is in-group virtue signaling.
             | 
             | > We have more than enough homes.
             | 
             | If that were true, more people could afford them.
             | Affordability scales with the rate of new builds.
             | 
             | > There are over two dozen empty homes per homeless person.
             | 
             | Notwithstanding that this is unsourced, lodgment =/= home
             | ownership and homelessness is its own special problem that
             | includes factors beyond cost.
             | 
             | > Hence the need for a social solution.
             | 
             | We have those, and they're only being expanded.
        
               | wizofaus wrote:
               | > Families can decide for themselves what suits them.
               | 
               | But they only can choose from what gets built, and what
               | gets built is ultimately a function of what builders
               | consider profitable and what legislation allows. And what
               | legislation allows is based, to a significant extent, on
               | what infrastructure can be provided to support particular
               | types of residences. If a government decides it can't be
               | bothered (or afford) upgrading or building the necessary
               | infrastructure to support more apartment dwellings then
               | families aren't going to get to choose living in them.
               | Similarly, what's profitable depends on how taxes and
               | other fees are levied from profits made by property
               | developers and owners etc. Families don't get much choice
               | over that either.
        
               | slothtrop wrote:
               | > a function of what builders consider profitable and
               | what legislation allows
               | 
               | Change legislation (qua zoning, qua regs) and you
               | increase the rate of builds, which should adequately meet
               | current demand. Of course, the laws of physics are in
               | play - if the immigration rate is high, thereby
               | perpetually increasing demand, you still won't build fast
               | enough.
               | 
               | This is what YIMBYs have to remember about Japan, which
               | they frequently cite. The population doesn't grow much.
               | Can't have it both ways: build, or reduce immigration.
        
             | WheatMillington wrote:
             | You can live in your human storage compartment. I'm happy
             | in my house, thanks.
        
           | luis_cho wrote:
           | We could add taxes for cement that could be redirected to a
           | carbon dividend.
           | 
           | There is a environmental cost that we are not paying when we
           | build houses, and having a tax it's a fair way to incorporate
           | this externalities. I don't trust the state with the money
           | from this taxes so lets share them equally with the
           | population.
           | 
           | We can do the same with aviation that would also reduce
           | speculation of the house prices.
        
         | ayemel wrote:
         | The US is currently on shoring a significant amount of
         | manufacturing, need new builds to support this.
        
         | robertlagrant wrote:
         | Three possible, not-mutually exclusive answers:
         | 
         | - Fewer families now then before
         | 
         | - Significant net movement of people (e.g. the UK took in 0.6m
         | immigrants in 2022, pushing up housing requirements) resulting
         | in more houses being needed in some locations even if the world
         | had zero extra people
         | 
         | - Cement isn't reusable, so once it's set it's only useful in
         | that place
        
           | Velofellow wrote:
           | cement [?] concrete, but concrete is indeed recyclable. I
           | know TxDOT (likely other agencies and municipalities) allows
           | its use, often as aggregate material for HMAC paving. The
           | cured concrete is crushed, sorted by gradation and used
           | accordingly. Concrete rubble can also be used in retaining
           | walls along with some backfill applications.
           | 
           | https://www.dot.state.tx.us/business/contractors_consultants.
           | ..
        
           | londons_explore wrote:
           | Most concrete products can be recycled.
           | 
           | But, due to the very low cost of cement and other related
           | products, it is rarely economical to transport end of life
           | concrete far to be reused.
           | 
           | However, if there are effective taxes on disposing of
           | concrete (as there are throughout the EU+UK), then concrete
           | does tend to get reused.
        
         | StefanWestfal wrote:
         | That is true for a lot of western countries but we are expect
         | to produce and consume more concrete until 2050 then we did so
         | far in history in developing countries.
        
       | roywashere wrote:
       | I think it is interesting to see that hannob who wrote many
       | articles on IT security now seems to have pivoted to covering
       | 'green and energy' topics. All submissions to HN in the last year
       | are not about IT!
        
       | LatteLazy wrote:
       | We need as many ways to theoretically cut emissions as possible.
       | That way, no one way will ever have to be chosen by a majority of
       | people. So we will never have to actually do any of them. And we
       | can keep polluting but pretend "it's not my fault because I
       | supported <insert random niche idea>".
       | 
       | No one wants to admit they are happy to just ruin everything. So
       | we all need to pretend we want action. But in order to prevent
       | any action happening we need to pick different things.
       | 
       | The Nuclear people won't vote for solar expansion, the solar
       | people will deny windmills work, the windmill people will refuse
       | to condone nuclear. That way EVERYONE can claim the moral high
       | ground AND use nice cheap, reliable coal. The same applies for
       | everything (electric cars? No! Hydrogen!. Hydrogen? No, public
       | transport! Public transport? No, electric cars!).
        
         | gs17 wrote:
         | > The Nuclear people won't vote for solar expansion, the solar
         | people will deny windmills work, the windmill people will
         | refuse to condone nuclear.
         | 
         | I have only ever seen the last of these outside of people
         | selling something.
        
           | LatteLazy wrote:
           | Go look at any HN article on either and you will find people
           | talking about wind farms being ugly, being intermittent,
           | making noise, killing birds etc.
           | 
           | The point being that no solution is perfect and by refusing
           | any imperfect solution we get what we really want: no action.
        
         | yazaddaruvala wrote:
         | I understand why you feel demotivated by all of this negative
         | discourse and constant speculation on better technology. That
         | said,
         | 
         | > electric cars? No!
         | 
         | The Model Y was the best selling car[0] in the world in Q1!
         | Isn't that a positive fact :)
         | 
         | Six Flags in California now has solar installed at 2 of its
         | theme parks, offsetting 3000 homes worth of electricity! Isn't
         | that a positive fact :)
         | 
         | There are many other stories like this, you just have to look
         | :)
         | 
         | > So we will never have to actually do any of them.
         | 
         | I agree we can do more, but focus on these positive outcomes!
         | Stuff _IS_ happening and it is for the better!
         | 
         | [0] https://finance.yahoo.com/news/tesla-model-y-was-the-best-
         | se...
         | 
         | [1] https://pv-magazine-usa.com/2023/04/25/six-flags-
         | announces-s...
        
       | pfdietz wrote:
       | The most interesting thing I saw in that article was the rotating
       | air heater. Induce turbulence and shock waves in air and heat to
       | very high temperature, without having a resistive heating element
       | that has to be at least that hot.
       | 
       | If you are going with electrical energy -> heat, you can get
       | energy storage for free. It's much cheaper to store a kWh of high
       | grade heat as sensible heat than it is to store a kWh of
       | electrical energy in a battery. So electrification of cement
       | production will be able to act as a large amount of dispatchable
       | demand, simply by tacking on a heat store.
        
       | Fyrezerk wrote:
       | This article isn't very clear on the fact that CO2 can be re-
       | injected back into the cement later in the production stage. I
       | work with a startup using direct air capture tech to capture
       | ambient CO2, store it, and inject it back into cement production.
       | This has a massive offset in the CO2 produced during the
       | calcination stage.
       | 
       | https://www.carbon-direct.com/insights/direct-air-capture-to...
       | 
       | There is also lots of work already underway on electrified
       | calcination. Plenty of industries, such as carbon fiber
       | production, already take advantage of electrified kilns in their
       | production process. This tech just needs to be scaled up. As the
       | article mentioned, cement manufacturing isn't exactly on the
       | cutting edge of technology.
        
         | megaman821 wrote:
         | Won't cement slowly reabsorb half of the CO2 it released when
         | making it (excluding the heating part)? What is the big
         | advantage to making it reabsorb it early in its lifetime?
        
           | waldothedog wrote:
           | 1. That's a big half 2. The heating part releases an
           | incredible amount of carbon
           | 
           | (If I can dig up some solid links after dinner I'll edit the
           | post. But Chris Magwood at The Endeavor Center has some
           | fantastic reference material for lifecycle carbon
           | intensiveness)
        
         | labster wrote:
         | How is the carbon bound in the concrete? I doubt CO2 bubbles
         | would last very long, so is it just forming carbonates?
        
           | Fyrezerk wrote:
           | [flagged]
        
         | NathanaelRea wrote:
         | How much compressive stress is lost when you aerate concrete?
         | Would consolidation with a concrete vibrator release the CO2
         | like shaking a soda?
        
           | Fyrezerk wrote:
           | [flagged]
        
         | pfdietz wrote:
         | > This article isn't very clear on the fact that CO2 can be re-
         | injected back into the cement later in the production stage.
         | 
         | How can that work? The calcium oxide (or hydroxide) reacts with
         | silica to make silicates, which bind things together. That CaO
         | which reacted is not available to soak up CO2.
        
           | Fyrezerk wrote:
           | In this particular case the CO2 mineralization is taking
           | place in a wastewater slurry that comes from washing out
           | cement trucks. The carbonated slurry is then re-used as an
           | additive by cement manufacturers.
        
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