5 ms·

Yes and no. Having worked in building construction, both classes of coatings would have relevant applications. I was going to complain that Mapei has not releas

Yes and no. Having worked in building construction, both classes of coatings would have relevant applications. I was going to complain that Mapei has not released any technical details, but it appears they have: https://www.mapei.com/it/en/news-and-events/event-detail/2019/11/04/mapei-research-and-technology-for-tecla https://www.mapei.com/it/en/news-and-events/event-detail/201... However, that their "water-repellent" provides "waterproofing" does not clear things up.

Animats 5y ago
The actual products that make it work: Mapesoil 10.[1] "High-performance, fibre-reinforced powdered stabilising agent for sports sub-base contruction surfaces".The amount of Mapesoil 10 required is 3%-5% of the dirt weight. Comes in 500kg bags, on pallets. Dynamon SR4 [2] "Superplasticizer based on acrylic polymer for concrete with long slump retention". About 1%-2% of the mix. That gets the material through the 3D printer without clogging. Planicrete [3] "Synthetic-rubber latex to improve the adhesion of cement mixes". About 2% of the mix. That helps each layer adhere to the previous layers, the usual problem with 3D printing. These are all standard additives for concrete. There's also a waterproofing agent sprayed on afterwards. The same materials would probably work with concrete forms. Plus, then you could do tamping. The trouble with most of these 3D building systems is that there's no tamping or ramming to solidify the material. It's just squirted on like toothpaste. So problems with voids and leakage are to be expected. All this requires the right dirt. Probably something with a high clay content. Too much sand or too much topsoil and it probably won't become hard enough. As with rammed earth construction [4] this may not hold up in wet climates. [1] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/5904_mapesoil100_gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [2] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/688_dynamonsr4_gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [3] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/701-planicrete-gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [4] https://www.firstinarchitecture.co.uk/rammed-earth-construction/ https://www.firstinarchitecture.co.uk/rammed-earth-construct...
- Animats 5y ago
  The 3D building printer people still don't have a good way to do compaction. Something like the Lil' Bubba curb machine.[1] It's a simple little device for making concrete curbs. You put in concrete, and it compacts and rams it into the curb it is making, pushing itself along. Something like that is needed at the output end of the 3D printing arm. [1] https://youtu.be/A06vfELMIK8 https://youtu.be/A06vfELMIK8
  - prawn 5y ago
    I used to wonder about something like Lil Bubba bringing in and compressing dirt to make agriculture borders/fences/windbreaks about 3-4' high. Imagine a grape harvester that straddles rows, bringing in dirt like a zipper. Of course, wouldn't be useful in all cases or maybe any, but running post and wire fencing for hundreds of kilometres in the outback must be brutal.
    - Animats 5y ago
      When you see rock walls around fields, it's often partly to dispose of unwanted rocks in the fields. “This is an awesome amount of manual labor, but it is trivial when compared to the much larger effort of getting stones to the edges of the fields in the first place.”[1] An extreme case is western Ireland. Tiny plots surrounded by far too many stone walls. Pretty, but too rocky for sustenance farming. Cromwell ordered the Catholics to go "to hell or to Connacht". [1] https://www.earthmagazine.org/article/history-science-and-poetry-new-englands-stone-walls https://www.earthmagazine.org/article/history-science-and-po...
- Animats 5y ago
  When you add up all the additives, it's about the same as the percentage of cement in concrete. This isn't "raw earth".
- kragen 5y ago
  Thank you for finding this wonderful information. In adobe construction, too-high clay content can be as big a problem as too low. All clays are somewhat expansive, and the most plastic clays like bentonite are also the most expansive. If your adobe is too expansive it cracks when it dries and contracts. Including enough sand makes it less expansive and less plastic when it gets moist, and including enough straw† allows it to resist cracking. When you need to build in adobe, you analyze the local soil first. If there's topsoil, you dig through it to get to the clay, sand, and silt that you need. If there's too much clay or silt, you can defecate some sand in a settling tank and pour the mud off the top. If there's not enough clay, you do the same thing but it's the mud you use instead of the sand at the bottom. If your clays are too expansive, or you have way too much silt, you may need to dig somewhere else, or grout your adobe with lime or ashes like they're doing, which shades into building with cement, as you say. We have thousands of years of craft lore about how to get this to work, plus modern science. It's true that, like rammed earth, adobe works best in dry climates, but its range extends into wetter climates than you might think, especially in the wattle-and-daub form where you supplement the straw with wood. The big problem with adobe nowadays is not that it doesn't hold up or that you can't make the soils work; it's that it's a hell of a lot of work because your walls are two meters thick, and they're nearly as dense as concrete, and it's slow, because you need to cure the bricks for months before you start construction. A double-wide trailer is just a lot more house for the money. The potential advantage to 3-D printing your adobe or concrete instead of tamping it into forms, plastering it on layer by layer, or stacking it up in bricks is that you can deploy the material where you think it'll be the most advantageous. The ruffled outside surface will channel rainfall into the grooves where more of it can flow down the wall before it soaks in. Those big spaces you see inside the walls might help with insulation, they will slow leaching of water that can produce moisture or efflorescence indoors, they might let you cure the adobe in place in the wall instead of in a pile of bricks beforehand, and they remove most of the weight of the wall without reducing its buckling resistance. The dome-vault shape allows you to reduce your roof expenses greatly. And maybe squeezing toothpaste out of a CNC crane will be less work than a team of sweaty guys tossing 20-kg bricks up ladders all day. Still, though, those gorgeous soaring vaults make me very nervous. An adobe wall collapsing on top of your kids would not be very fucking funny at all. ______ † I guess straw is a "high-performance fibre-reinforced stabilizing agent". The amount used is typically around 1%, so maybe straw is higher-performance than Mapesoil, or maybe they're just arching the walls more than you would normally dare to do with adobe.

Animats 5y ago

The actual products that make it work: Mapesoil 10.[1] "High-performance, fibre-reinforced powdered stabilising agent for sports sub-base contruction surfaces".The amount of Mapesoil 10 required is 3%-5% of the dirt weight. Comes in 500kg bags, on pallets. Dynamon SR4 [2] "Superplasticizer based on acrylic polymer for concrete with long slump retention". About 1%-2% of the mix. That gets the material through the 3D printer without clogging. Planicrete [3] "Synthetic-rubber latex to improve the adhesion of cement mixes". About 2% of the mix. That helps each layer adhere to the previous layers, the usual problem with 3D printing. These are all standard additives for concrete. There's also a waterproofing agent sprayed on afterwards. The same materials would probably work with concrete forms. Plus, then you could do tamping. The trouble with most of these 3D building systems is that there's no tamping or ramming to solidify the material. It's just squirted on like toothpaste. So problems with voids and leakage are to be expected. All this requires the right dirt. Probably something with a high clay content. Too much sand or too much topsoil and it probably won't become hard enough. As with rammed earth construction [4] this may not hold up in wet climates. [1] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/5904_mapesoil100_gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [2] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/688_dynamonsr4_gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [3] https://cdnmedia.mapei.com/docs/librariesprovider2/products-documents/701-planicrete-gb.pdf https://cdnmedia.mapei.com/docs/librariesprovider2/products-... [4] https://www.firstinarchitecture.co.uk/rammed-earth-construction/ https://www.firstinarchitecture.co.uk/rammed-earth-construct...

Animats 5y ago
The 3D building printer people still don't have a good way to do compaction. Something like the Lil' Bubba curb machine.[1] It's a simple little device for making concrete curbs. You put in concrete, and it compacts and rams it into the curb it is making, pushing itself along. Something like that is needed at the output end of the 3D printing arm. [1] https://youtu.be/A06vfELMIK8 https://youtu.be/A06vfELMIK8
- prawn 5y ago
  I used to wonder about something like Lil Bubba bringing in and compressing dirt to make agriculture borders/fences/windbreaks about 3-4' high. Imagine a grape harvester that straddles rows, bringing in dirt like a zipper. Of course, wouldn't be useful in all cases or maybe any, but running post and wire fencing for hundreds of kilometres in the outback must be brutal.
  - Animats 5y ago
    When you see rock walls around fields, it's often partly to dispose of unwanted rocks in the fields. “This is an awesome amount of manual labor, but it is trivial when compared to the much larger effort of getting stones to the edges of the fields in the first place.”[1] An extreme case is western Ireland. Tiny plots surrounded by far too many stone walls. Pretty, but too rocky for sustenance farming. Cromwell ordered the Catholics to go "to hell or to Connacht". [1] https://www.earthmagazine.org/article/history-science-and-poetry-new-englands-stone-walls https://www.earthmagazine.org/article/history-science-and-po...
Animats 5y ago
When you add up all the additives, it's about the same as the percentage of cement in concrete. This isn't "raw earth".
kragen 5y ago
Thank you for finding this wonderful information. In adobe construction, too-high clay content can be as big a problem as too low. All clays are somewhat expansive, and the most plastic clays like bentonite are also the most expansive. If your adobe is too expansive it cracks when it dries and contracts. Including enough sand makes it less expansive and less plastic when it gets moist, and including enough straw† allows it to resist cracking. When you need to build in adobe, you analyze the local soil first. If there's topsoil, you dig through it to get to the clay, sand, and silt that you need. If there's too much clay or silt, you can defecate some sand in a settling tank and pour the mud off the top. If there's not enough clay, you do the same thing but it's the mud you use instead of the sand at the bottom. If your clays are too expansive, or you have way too much silt, you may need to dig somewhere else, or grout your adobe with lime or ashes like they're doing, which shades into building with cement, as you say. We have thousands of years of craft lore about how to get this to work, plus modern science. It's true that, like rammed earth, adobe works best in dry climates, but its range extends into wetter climates than you might think, especially in the wattle-and-daub form where you supplement the straw with wood. The big problem with adobe nowadays is not that it doesn't hold up or that you can't make the soils work; it's that it's a hell of a lot of work because your walls are two meters thick, and they're nearly as dense as concrete, and it's slow, because you need to cure the bricks for months before you start construction. A double-wide trailer is just a lot more house for the money. The potential advantage to 3-D printing your adobe or concrete instead of tamping it into forms, plastering it on layer by layer, or stacking it up in bricks is that you can deploy the material where you think it'll be the most advantageous. The ruffled outside surface will channel rainfall into the grooves where more of it can flow down the wall before it soaks in. Those big spaces you see inside the walls might help with insulation, they will slow leaching of water that can produce moisture or efflorescence indoors, they might let you cure the adobe in place in the wall instead of in a pile of bricks beforehand, and they remove most of the weight of the wall without reducing its buckling resistance. The dome-vault shape allows you to reduce your roof expenses greatly. And maybe squeezing toothpaste out of a CNC crane will be less work than a team of sweaty guys tossing 20-kg bricks up ladders all day. Still, though, those gorgeous soaring vaults make me very nervous. An adobe wall collapsing on top of your kids would not be very fucking funny at all. ______ † I guess straw is a "high-performance fibre-reinforced stabilizing agent". The amount used is typically around 1%, so maybe straw is higher-performance than Mapesoil, or maybe they're just arching the walls more than you would normally dare to do with adobe.