Project Kamp: Sustainable Construction Methods
Before I got involved in the PP Community I used to teach sustainable construction methods.
With Project Kamp pulling on many different types of sustainable construction methods to create the community I wanted to create a simple breakdown of the possible methods we could use.
Description: Biocrete replaces elements of the Sand/Aggregate with organic waste material such as hemp, coconut fibre, and rice husks to create a material that has a lower carbon footprint than standard cement.
-Similar construction methods to standard cement.
-Low carbon footprint.
-Uses waste materials
-Biocrete is known for its natural cooling properties in warm climates.
-Heavily cement/lime based
-Takes longer to cure than standard cement
Speed: Fast (utilises existing machinery)
Cost: Low (cement is cheap and free elements)
Documentation: Extensive (depending on the bio-element)
Description: Clay, sand and sometimes a little cement are mixed together and “rammed” to create a durable and very cheap construction technique.
-Carbon neutral if near sources of materials
-Durable construction dry climates
-Thermal mass of walls create a comfortable climate within the structure in warm locations
-Labour intensive construction
-Not suitable for wet regions unless the earth structure is plastered or protected in another way.
Documentation; Well documented.
Description: Strawbales are stacked within a timber structure to create a well insulated and durable structure made from mostly waste materials.
-Carbon negative and great for rural areas.
-Good insulation properties
-Very thick walls-Requires a timber structure
-Hay needs to be treated to prevent infestation
Documentation; Well documented.
Description: Plastic bottles are rammed full of either plastic waste or sand if construction is needed to be faster and then stacked side by side like bricks with mud or concrete mortar holding the blocks together. More durable methods use chicken wire to strengthen the structure if needed.
-Made from 80% waste material
-Cheap to build with
-Hard to recycle in the future
Documentation; Well documented.
Description: A exciting community who are awesome, developing a great way to save the world from plastic pollution (duh!). Currently beams have been developed but are very slow to produce if you wanted a building, however V4 shows the potential of creating key elements to solve these problems
-Made from 100% waste material
-Cheap to build-Strong durable materials
-Unknown structural strengths
-Plastic is not great exposed to UV and would either need to be painted or covered.
Documentation; Well documented, but not in construction.
Description: Using shredders fine plastic is mixed with cement to create concrete block or poured into structures.
-Uses large volumes of PET, with or without labels.
-Similar to standard construction methods and easily taught to communities.
-Plastic is no longer recyclable in the future.
Documentation; Well documented, but no manuals.
If you have any questions/suggestions or would like to compare one I have missed, comment below!
Image is a building I built out of bamboo, biocrete and reclaimed timber over 2 months.
This is an interesting question and depends on the way the PET is shredded.
The closest thing we can use compare to compare the effects of adding plastic to a material is with PET mixed with Plastic Crete. If the ratio of binding vs aggregate gets too low a significant change occurs in strength. 1:2 seems best (Cement : Aggregate) However that aggregate can range with <10% PET to sand mix increasing strength and with 50%-20% gradually decreasing the strength.
In this paper here the source shows the trend between shredded size, and strength with size making a major difference. Another paper does use smooth PET in strands which is too interesting and better effects.
I guess the real question is how long are the fibres we can create, and how rough is their surface by using PET. Because what we want to create are a copy of these plastic industrial standard fibreglass reinforcement for cement. Thus ensuring an improvement in strength rather than a reduction.
Yeah – I was thinking in terms of long strands, rather than flakes. Maybe like the size of paper strands that come from a non-cross-cut document shredder. Alternatively bottles could be split into long thin threads which are then chopped into the optimum length for mixing – like your illustration.
I think it might be time for some tests… 😉
When building eco-buildings in South America I used recycled Tetra Pak cartons which had been converted to sheets for the roof.
The process looks a lot like the new sheet press being developed by V4. Unlike most plastics, Tetra Pak is not widely recycled in Europe and often discarded.
Does Tetra Pak get recycled in your area?
@rorydickens – that video is fascinating.
I see they are wrapping a layer of polyethylene around the shredded material, which I guess will help to ensure the outer surfaces are well bonded and moisture resistant. I wonder what the water absorbency is like, at the trimmed edges. Looks like an interesting material to work with (a bit like MDF – but bonded with thermoplastics rather than thermosetting urea-formaldehyde).
p.s. the tetra paks where I live go straight to the municipal incinerator, to be turned into heat, electricity, and atmospheric CO2.
Here are some photos of the material close up so you can hopefully copy the results. In the photo with the fibres, this was actually defect batch that we received. They came in different thicknesses and felt like Onduline (a thick roofing material you can find in some hardware suppliers in Europe) Fairly flexible and very good at insulating a building. Screws went in nicely and the plastic coat in the video gave the material a shine.
The real unknown here that affects viability is heating time, pressure and temperature. If these are known we can replicate fairly easily if we can assume the mix has no additives.
Good question, however I never saw any bloating of the material after exposure to moisture. Maybe an additive is added to the pulp? or the Plastic ratio is high enough to restrict expansion/deterioration of the bonds.
Thank you, these photos really help.
I also went over the video again ( https://www.youtube.com/watch?v=8J3_lgDVrdo for those tuning in later) with a fine tooth comb (half speed, pausing every scene), and I found no real evidence of additives other than the wrapping layer of polyethylene.
Not even in the background, where it should have been visible in large quantities, because of the size of the operation.
It looks like the hot press is steam powered (compression and heat), and presses for a long time (it feels like the timer ‘stops at 13:54:00’ as this final ‘second’ feels longer than the previous ones, but it could just be me 🙂 ).
As for the pressure: photo 1
Photo 2 should also bring some information, but I’m not familiar with the gauges used, maybe an engineer can guestimate their values ( @frogfall ?)?
An interviewee at one point says “after the grinder it goes for proper mixing”
Then there is the number 14.65 when weighing the raw material (photo 3)
This could be kilos, but it’s odd this number should be this exact, when the filling of the molds in the next scene is actually quite messy…
This would suggest their is a step missing in the video(!) as and exact number would be needed for creating a mix, that you later can ‘mess about’ with.
As this is an ‘environmental’ video, selling the public on the idea of 100% recycled tetra, this is a part I would also leave out, just to avoid confusion.
Or is this where they add the radioactive waste? (cue omnious music)
As for the ‘sides’ of the material, they simply seem to be left ‘raw’ (no evicence of treatment after cutting), which (in the Netherlands) I would add as an extra step.
I would guess an extra 0.35/5/10kg of polyethylene is added to the mix.
What do you guys think?
Bonus videos I got:
Regaining the plastic and alluminium from tetrapak.
Just as a sidenote the guy in the video says: “after the first mechanical (vortex!) seperations we already get 3 different plastics at a quality rating high enough to be ready to be reused”.
A must see for anybody trying to seperate, well anything (including plastics).
In German (no subtitles).
Home recycling tetra packs…
I’ll have to look at the video again. The “mixing” comment might mean they are adding something (at a guess, it would be extra PE – from a different waste stream). Tetra Pak already has a PE layer inside the aluminum layer.
“Kilogram force per square centimetre” is a stupid pseudo metric unit of pressure. It should have been killed off years ago, but Americans seem to be fond of it, as they can’t understand SI. One kg/cm2 is close to one atmosphere or one bar or 100 kilopascals. The gauge also shows psi (pounds per square inch).
I’m guessing this is the hydraulic pressure in the rams (?). Without knowing the diameter and number of rams, it can’t tell us the force being used – or what that would equate to as pressure on the sheet. I’ll look at the video again later today.
Please do, and I’ll give you an extra thought I had after watching the “Tetrapak cartborard recycling demo”-video (she actually shows roofing material in the end of the video(!))
What if they are actually discarding the cardboard to be recycled elsewhere?(!)
There appear to be two different output streams, One ‘cartboard coloured’ (which would make sense) and “one plastic sheet” coloured (by lack of a better description).
In other words, the final product might not contain as much paper as we might think, which would also make it waterproof…
I also looked at this: https://www.youtube.com/watch?v=8RALULvgapI
Which is another “wet” system (again in Germany). In this one they are definitely concentrating on separation of the different components. Interestingly, they talk about removing “contaminants” – and while they might be talking about the plastic and aluminium, it could also refer to the food residues that will be left in the cartons. The Mumbai process seemed to involve dry “grinding” of the cartons – so any food residues would still be present – and it might make fibre separation more difficult.
And yeah, I also saw that the plant in Mumbai seemed to have different types of end product. But it looks like they also have other feedstock (shredded paper & old packaging material) which could conceivably be going into the “cardboard”.
I guess we could be seeing a whole bunch of different “grades” – as the film editors will be more interested in showing people working than highlighting details of the process or products (people are more photogenic 😉 )
The tile and plant pot shown at the end of the “hobby recycling” video are certainly “aluminium rich” – and also quite stiff. The sheets at the Mumbai factory seem quite flexible in comparison – and possibly seem more colourful than shiny – so could be a different mix. On the other hand, the benches seem quite shiny…
Yes – it is difficult to guess what is going into these products.
Image of the bench…
As the plastic and alluminium are also listed as an output, I don’t think they are considered a contaminant, so they probably mean the food residu, indeed.
It also looks like an elaborate ‘rinsing’ system, which would confirm this..
The water could probably be filtered by Duckweed, but let us stay on this topic 😉
Would we agree that recycling tetrapaks by seperating the paper from the plastic/alluminium would result in a very interesting product (and cardboard)?
Plastic AND alluminium would make great roofing material.
The amount of cardboard that could be left in this mix (mmm, “after the grinder it goes for proper mixing”-flashback) might be the variable we are missing, but why bother with cardboard in an ocean of tetra?
This image at wikipedia supposedly shows the different layers of a tetrapak carton. It doesn’t indicate the thicknesses of each layer, unfortunately, but that information might be out on the web somewhere.
I’ve found a few more references:
The biggest layer is the paper layer, which makes up 75% of the packaging, otherwise 20% is polyethylene and 5% is aluminum.
It doesn’t say if the percentage is by mass or by volume, unfortunately.
Fibre recovery : Paper mills recycle Tetra Pak cartons, either separately or together with other paper grades, by separating paper fibres from polyethylene and aluminium using a water-based process known as repulping. The virgin fibres used in Tetra Pak products are specially selected to give maximum strength and stiffness for the lowest possible weight. When recycled, these fibres provide a valuable raw material for new paper and board products. Recovery of non-fibre components:Recovery and recycling of aluminium and polyethylene extracted during the repulping process varies from country to country. For example, in Finland one paper mill recovers the energy to generate steam that is used either for drying pulp or producing electricity. This mill also generates aluminium powder for re-smelting.In Germany, repulping residues are used in cement kilns where polyethylene serves as a high-energy fuel. The aluminium is recovered as aluminium trioxide, which is an essential ingredient in cement.Suitability for energy recoveryTetra Pak cartons have a high calorific value, generally in the range of 20-25 MJ/kg, and are therefore suitable for energy recovery.The calorific value of the non-fibre polyethylene and aluminium components available after the fibre recycling process is typically around 30 MJ/kg.Tests have shown that Tetra Pak cartons are comparable to bio-fuels such as wood chips and bark in terms of emissions.
The roofing product photos @rorydickens posted look quite fibrous compared to the tile & plant pot, which suggests the corrugated sheets might have been “whole tetrapak”. The question is, I guess, would 20% PE be enough to bind and waterproof the mix?
That’s why I think they extract at least some of the cardboard for the ‘proper mix’.
I guess it would come down to running some experiments.
I’ve already asked some people to start saving their tetra for me (never touch the stuff myself 😉
I’ll start with the simple blender DIY paper/other seperation and play around with my heatpresses to see what’ll happen.
I invite others to do the same, so we can compare notes later on.
Don’t know if the headquarters is also recycling Tetra at the moment, but I’ll bring it up on Monday.
It looks very simple and thus promising.
Tetra and cans might even equal free alluminium molds…
…though I don’t have a rocket stove (yet).
Well, there’s your answer 🙂
No cardboard, just an aluminium and polyethylene ‘alloy’.
And if have you no need for driving your tank over the roof, you could leave some cardboard…
6 Roof and Pavement Tiles from Plastic Waste:
Especially the version where used motoroil is added(!)
Might be a solution for those oil contaminated containers…
Hey @donald @frogfall!
Thank’s for this topic, it’s really inspiring.
Do you think this PolyAl alloy have comparable properties than metallized films? Would similar output products be possible to achieve with silver coated packaging?
@rorydickens : In Switzerland, few tetrapacks are half-recycled: the cardboard is recovered and the PE-Al is incinerated (see this website, in French or in German). Large scale collection is not yet established though: a pilot test was done with Aldi Switzerland but, due to a “too large demand”, Aldi did not reconduct it. The decision is now to be taken by big economic actors and politics.
It’s fun doing the research 🙂
This PolyAl aloy is of course more ‘entropic’ than a neatly ordered metalized film, so I would not dare compare properties, unless I could actually test them.
Thickness would already be one major difference…
Conductivity… I also hope not. Wouldn’t want a lightning rod as a roof!
Tetrapaks are reasonably standardized, don’t know if you can say the same about the ‘silver coated packaging’. But if it’s possible to ‘type sort’ them, I see no reason why it should not work.
Hi @marcvdv @donald
Coincidentally, I was doing a few tests on metallised plastic packaging yesterday. I tried running the items shown below though a small electric document shredder. It wasn’t all that successful, as it wasn’t powerful enough to get through more than one layer at a time – so jammed at the joints 😉
Both materials appear to be about 0.2mm thick, and a float/density test in water showed that pieces have a neutral buoyancy.
I was wondering if shredded aluminized film could be effective as insulation in wall panels (flamability could be an issue), or maybe they could be used as reinforcement in mud brick.
The wikipedia article on metallised film says that the most common films used are “oriented polypropylene” or PET. It seems that the old original Mylar used BoPET. The labels on the back of the packaging don’t help. They just say “Plastic – not currently recycled”. It seems some of these materials could even have PET on one side of the aluminium, and polyethylene on the other.
So we probably couldn’t get the exact same properties in a heat/pressure moulded sheet as with the TetraPak-derived material. But the properties might be just as interesting, for other reasons 😉
Yeah, that;s why I’m going for the blender test once I have material 😉
Growing my own greens and hardly eating any processed food leave me with almost no waste to experiment with.
Luckily I have friends that still do….
A blender would also not just ‘cut’, but also smash, squeez and pull the materials, which in this case might be a benefit.
I think with the metalized films the old “1 is waste, 1000 a resource’ might be applicable.
Sort them by ‘product’, scan the EAN (barcode) into a spreadsheet, run tests to find similar packages, group them by composition (in the spreadsheet), use them together.
The EAN spreadsheet should be shared, any avarage web-programmer can program a website: scan the barcode -> get the composition.
EANs should be unique (there is a central database), but even if they overlap a simple product photo can do further optical sorting… etc.
The PolyAl seemed pretty fire retardant…
The PolyAl seemed pretty fire retardant…
n.b. The external cladding on London’s Grenfell Tower was aluminium and polyethylene. How a material behaves in-situ is often very different to how it behaves in a simple demonstration (orientation, and induced air flow, make a huge difference).
Thank’s @frogfall @donald for the reply. Great thing is that I’m staying in Asia (Nepal) to run my test. The major producer of noodles produces 2100 packets a minute; so the 1000 a resource is definitely applicable.
Before leaving, I had access to an infrared spectrometer and ran tests on 8 random noodle packaging (export grade) and they all matched with polyproylene on the library.
Concerning shredding, we’ll start with scissors. Then, I have different creative ideas on the scale-up phase.
This discussion takes a different direction than the original subject. I invite you to follow our progress (and to help solving our problems) on this topic :).
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