Space elevators!

(The original process is documented in the Nature article: https://www.nature.com/articles/nature25476)

I suspect the issue with the other use-cases you mentioned is that it's very rigid. It isn't at all ductile or bendable the way steel is. It would either need to be pressed directly into the shape you need during manufacturing or pressed into a large piece of raw stock then subtractively processed to get the shape you need.

Pressing might be economic for standard profiles like beams but it won't be for pieces like the chassis of a car.

To be clear, "pressing" here doesn't just mean a standard hydraulic press, the press also needs to be heated and the wood needs to be held under pressure for a while. You can't just stamp it the way you can with steel panels.

I don't know much about materials science, but I had a few classes about it.

Seems like their wood gets ~550 MPa in ultimate strength in tension. Seems like their material is brittle (so it behaves like a spring until it breaks), therefore you probably want a safety margin, because at 550 MPa it breaks. Note the unit is a Force/Area, you can compare materials with the same cross-section. In compression they say it's about 160 MPa in axial load, it can be more or less in the other directions (due to wood having fiber it's not the same in all directions, and there they compress it perpendicular to the fiber so they get one direction stronger than the axial load and one weaker, but I guess for a beam you mostly care about axial strength). Torsion and flexion are directly dependent on compression, shear and tension, didn't find shear. Although I'm not entirely sure how it works for materials that aren't the same in all three directions like steel.

For steel, depends on the steel but a quick search (https://www.steelconstruction.info/Steel_material_properties and https://eurocodeapplied.com/design/en1993/steel-design-prope...) says ~200 to 400 MPa in tension for yield, at which point it starts changing shape instead of behaving like a spring, then 350 to 550 MPa for strength, at which point it breaks. I believe in multiple applications they do go apply forces where the metal bends a bit and adapts to its application, but I'm not sure. Regardless, that would mean the wood in tension is equivalent to very strong (presumably very expensive) steel.

In compression, steel is from 170 to 370 MPa apparently(https://blog.redguard.com/compressive-strength-of-steel, didn't find much else easily because numbers were strange on other sources), so I guess steel would win on that one.

But this is comparing the raw strength. In reinforced concrete, you add the metal for tension resistance, concrete is there to sustain compression, so it wouldn't matter much. For beams, the shape of beams is optimised to resist in the direction it needs (e.g. the H cross-section resists to bending in one direction). But you probably can't do that with their wood (they say for now they are limited in shapes), so you'd need more material, and probably it would be stronger overall since you have more material. Question then is how much material (in weight, compared to steel) do you need (they say 10 times less but it probably doesn't take into account the shape), and how much does it cost?

I'm guessing they could also make composite beams at some points too, with not only wood in them.

Then for mechanical applications, there might be also other things that enter the game. In their paper they needed to coat the wood so it wouldn't swell with humidity. For any application with friction, not great. Also, I wouldn't be surprised if it's more sensitive to friction than metals.

Note that the numbers are from 2018, they may have improved the process.

CLT is often faster because you can essentially just prefab it offsite and assemble it significantly faster and with less equipment and specialized workers than reinforced concrete. Steel needs steelworkers, plus concrete takes time to set and cannot be poured in all weather conditions.

While this isn't CLT I would imagine you still get most of the benefits (you can cut it to spec offsite and don't have to do anything special with it when it shows up)

It's kind of moot if the resulting product causes more emissions or is not reusable, bio-degradable or at the very least chemically inert, like steel is (citation needed).

If all of that isn't true, it's just aesthetics.

(most of what I know about this is from a video about making bamboo 'wood' products, which involves a lot of glue)

  Compressive strength
  Tensile strength
  Shear strength
  Flexural strength
  Torsional strength
  Impact strength
  Fatigue strength
  Hardness

I've sort of had the opposite idea in my head for a while (many years): I wish there were a site that only talks about stuff that's already released and available to consumers. I don't want any future promises, I don't want any pre-orders, I don't want any announcements for products that will only come out in months to years, not even supposed scientific advancements that haven't even resulted in any product yet and may never[0]. I want only stuff that's available right now already.

Hearing about future stuff has only ever made me feel worse. I want to just stop hearing about the future altogether. I wish promises and pre-announcements and whatever just didn't exist.

[0]: https://xkcd.com/678

>Ultimately, InventWood is planning to use wood chips to create structural beams of any dimension that won’t need finishing. “Imagine your I-beams look like this,” Lau said, holding up a sample of Superwood. “They’re beautiful, like walnut, ipe. These are the natural colors. We haven’t stained any of this.”

The strength is 483–587 MPa, I seem to see when skimming, which is indeed superior to ASTM A36 structural steel (250MPa yield strength). In Extended Data Figure 1c, they reported the density as 1.3g/cc, a sixth of the density of steel. (Extended data figure 2f plots density against lignin removal percentage.) Of course high-strength steels are stronger, but not six times stronger.

As for the process, they didn't just boil the wood; they boiled it with lye (2.5M, the "food industry chemical") and sodium sulfite (0.4M, technically also a food industry chemical, used for example as an antioxidant in wine) for 7 hours before densifying it with 5MPa for "about a day", removing optimally 45% of the lignin. This is similar to the sulfite chemical wood pulping process that preceded the Kraft paper process, just carried out at high pH and not taken to completion, so in a sense I guess the result is sort of like Masonite, which is also made from cellulose fibers from wood bonded with the wood's natural lignin.

Environmental concerns may be an obstacle; sulfite pulping is nasty. Also presumably to mass-produce the stuff they'll want to find ways to shorten the cycle time, and maybe already have.

The burning question that arises in my mind is why nobody was doing this in 01890, 135 years ago. Sulfite pulping was going gangbusters, building materials were booming, environmental concerns were largely unknown, and there was a rage for everything newfangled, modern, and "scientific". The scientific discipline of strength of materials, needed to calculate the benefits, was already well developed. Mason put Masonite into mass production in 01929, with a process involving autoclaving wood chips at 2800kPa. So what prevented someone from selling Superwood back then? Did nobody try partial alkaline sulfite pulping and pressing the result?

"First, natural wood blocks were immersed in a boiling aqueous solution of mixed 2.5 M NaOH and 0.4 M Na2SO3 for 7 h, followed by immersion in boiling deionized water several times to remove the chemicals. Next, the wood blocks were pressed at 100 °C under a pressure of about 5 MPa for about 1 day to obtain the densified wood"

Pretty simple and straightforward.

Correct me if I'm wrong, but almost all use cases for wood rely on it to be somewhat light, for which the lattice structure is already fairly ideal.

Compress the wood and then inject it with resin to stabilize it. Effectively it's only very partially wood and more resin at the end.

After double checking, the video references the science paper from the article, so yes, it's 100% the same process.

I don't know what the implications are for recyclability, but there's no mention of injecting other materials so perhaps it decomposes in a similar way to ordinary wood?

[1] https://www.nature.com/articles/nature25476

Laminated timber is also very construction-friendly. It can be worked with simple tools, and CNC machines allow for prefab components to be shipped to the site and assembled quickly with minimal fuss.

There are some plans for high rise construction with this material. E.g. there is a plan for a skyscraper in Tokyo (350 meters, 70 floors).

The adhesives used in laminated timber aren’t perfect. They’re very durable, which is great for structural integrity. But it also means the material breaks down more slowly in a landfill (if you decide not to recycle the material for some reason). However, newer adhesives used for this these days are less toxic and not that harmful in a landfill. And importantly, most of the material is actually just wood, not glue.

Ipe is actually not attractive for exterior structures. The wood is so dense, stains don't penetrate. Many let it age to a grey/brown patina with annual cleaning and sanding. Inventwood would be a better alternative for exterior work if they have coloring options during the manufacturing process. For Ipe, staining is expensive and time consuming due to it has to be stained like cabinetry, with two passes.