3D Printing

Inexpensive houses could be 3D-printed from peat

Inexpensive houses could be 3D...
The University of Tartu's Prof. Toomas Tenno, with test pieces of the material
The University of Tartu's Prof. Toomas Tenno, with test pieces of the material
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The University of Tartu's Prof. Toomas Tenno, with test pieces of the material
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The University of Tartu's Prof. Toomas Tenno, with test pieces of the material

Some of the earliest houses in Northern Europe were made out of slabs of peat, as it was a cheap and abundant building material. Now, Estonian scientists are revisiting the idea of peat houses, only this time they're looking at 3D-printing the things.

Peat is plentiful in Estonia, as it's found in the wetlands that cover approximately 22 percent of the landscape. Another thing that Estonia has a lot of is oil shale ash – the country produces an estimated 7 million tonnes (7.7 million tons) of the waste substance annually, only 5 percent of which gets repurposed.

To that end, researchers from the University of Tartu and the Estonian University of Life Sciences have created a 3D-printable concrete-like material made mainly from milled peat, with oil shale ash serving as a binder. Silica nanoparticles are also added to the mix.

In past efforts to create peat-based building materials, the chemical qualities of peat have prevented binders from hardening. Thanks to oil shale ash's very high pH value, however, that isn't a problem this time around.

The resulting material hardens within one day of being printed, although it still retains an elastic quality for some time after – this means that blocks of it can be stacked snugly together, without any gaps between them that would allow wind to pass through. It's also said to be strong, light, durable and incombustible (despite the fact that peat is commonly burned as fuel), plus it exhibits a low rate of heat transfer, and is good at blocking sound.

Additionally, the material is cheap. It is estimated that building a house shell with it would cost about one-tenth what it would cost to construct a traditional framed shell of the same size.

A paper on the research was recently published in the journal Sustainable Materials and Technologies.

Source: Estonian Research Council via EurekAlert

5 comments
MD
Rammed earth and adobe is a thing... Is the peat harvesting going to impact a pine martin habitat, or frog swale?? (environmentals always want to know things like that) But just because you have a new building plasticine, why the heck is 3D printing the first construction method that gets discussed.... (Zero slump mud in form free construction is nothing revolutionary..) Precast has a lot of quality benefits..... With Row by row "printing" how does one vertically reinforce structures ??? Don't forget that the construction industry is one place where 3D "printing" is nothing new, how do you think they made Hoover Dam, etc... Additive manufacturing. Some things will take off, others won't.
christopher
cool... until it falls over and crushes you to death. You cannot 3D print reinforcement, so this isn't ever going to meet a building code.
Nik
That sort of material will make an excellent home for rodents of all types, especially rats and mice, unless it is rendered totally with sand and cement mortar, or similar. A neighbour of mine recently added a window into a rubble stone and clay built house with walls 2 ft thick, and found a rat had burrowed upwards into the wall from beneath, and had made a comfy home inside her wall. 3D printing seems an excessively slow and expensive way to make blocks. Surely they could be made just by compressing into moulds the same as most blocks, or extruded and sliced off, as bricks are made.
Don Duncan
Wow, if this is cheaper than aircrete it might replace it before aircrete can replace concrete. But fireproof? That's hard to believe since both peat & shale ash are combustible. Also, "cheap", "strong", "light" & "durable" are relative. How does "the material" compare to aircrete, e.g., aircrete cuts the expense by 90% also.
Paravectorno Extactini
Anyone got a DOI? Could better see the path to LEED x shale ash x peat...oh, https://www.reddit.com/r/Futurology/comments/8zkyo8/these_3dprinted_houses_could_be_onetenth_the/ and http://dx.doi.org/10.1016/j.susmat.2018.e00067 and see the references at https://www.researchgate.net/publication/326257265_Novel_ecosustainable_peat_and_oil_shale_ash-based_3D-printable_composite_material if not other work by https://www.researchgate.net/profile/Ergo_Rikmann Reinforcement fans will want to hear that the construction seems to require a roof made of something else, and that (from abstract) compressive and bending strengths are (1.2 MPa and 0.36 N/mm², respectively.)