Bricks from sand and plastic

For all the wonder and splendor of the internet, it's fairly remarkable the sorts of things that CAN'T be found. It would be nice if there were some way of filtering the useful from the rubbish without close examination, but it seems the technological gurus at the top are currently content to grant access and have not yet figured out to eliminate noise.

A lovely example of a papercrete structure from
Green Home Building (great site with lots of resources)

This is a case in point. There are a good number of building techniques out there that rely on partially or entirely recycled materials (papercrete, using bottles as bricks, old tires and salvaged wood to name a few), but one of the materials that is conspicuously absent is by far and away the most troublesome trash of all: plastic. Some builders do incorporate plastic into their buildings (the plastic bottle building is a good example), but for most the use of plastic is limited in both scale and scope.

However, this should not, and does not need to be the case. Plastics are one of the most frequent inhabitants of our dumps both here and in the 3rd world, and have shown remarkable tenacity in showing up in places as far away as the Atlantic and Pacific oceans. But these very traits (the inability to break down under natural conditions and long term structural stability) are exactly what could make these a useful and unbelievably cheap building material.

Sloplast via siloplast.com

Doing a quick search for these materials pulls up a few easy links. One, of a company in UAE making bricks of plastic and sand (creating a material they call SIOPLAST). A search of Siloplast turns up lots of company websites, but no suppliers that I can find, as well as no instructions for making your own (unsurprising since it's a private company starting this in the first place). A bit further and you discover a brilliant German making blocks out of recycled bags that he terms Recy-Blocks. A search for the same only turns up ~1000 different websites and blogs parroting the same press release, but no actual suppliers or info on how to get or make these. Another brilliant technology most will never be able to actually use.

A plastic brick wall via recycledplasticblockhouses.com

Probably the best citation I could find was this fellow, who is making blocks using a homemade press and bailing wire (it appears the idea is similar to a cardboard compactor). It shows promise, has a fantastic write-up in Mother Earth news, and even more fantastically has drawings and details on how the press is made. As far as I can tell, this is the only site online that currently gives instructions on how to make building blocks from plastic.

I think that this ignores many of the inherent advantages of the plastic to begin with though. The process of bundling requires the transport of lots of plastic, and uses wire to bond. In short, this is a step forward (and I'm not trying to deflate the efforts of this work, what they're doing is great), but I see room for improvement and less waste. For example, using their brick size of 8"x8"x16" (weighing 6-10lbs each), building the outer wall of a 16'x20'x8' house like mine would require between 5-10 TONS of plastic overall (not accounting for doors and windows, no internal partitions), and ~ 24,000 feet of baling wire. It also utilizes types of plastic that would also ordinarily be recycled. That's quite a bit of transport and expense, and also a bit of extra work required to tie off each bale of plastic.

Which brings me back to Siloplast, and similar materials. The advantages here seem inherent to me, low transport costs (in Siloplast, the blocks consist of 70% sand, so local materials can be used), block consistency, and lower costs. It's just too bad there's nothing written on the net about the practicality of how to do this.

Except there IS.

The process of turning plastic and sand into bricks via ARRPET

Buried deep within the bowels of google results is this: a brief but informative account about this process being used in Egypt to produce "tiles, hexagon interlock, manhole covers and bricks." Unfortunately, this article only outlines the basic process, and not specific instructions on how to execute it. I'll need to further look into the process, although there are a couple of other mentions of it on the web, there's very little practical application information that I can find.

But a couple of very important points to make here:

These blocks are made out of ONLY sand, plastic and heat - With the exception of sorting and the preparation of the original plastic, the entire process is remarkably simple. From the description:

"The process of recycling the plastic rejects starts by the preparation of one cubic meter of sifted sand and adding it to one ton of mixed crushed plastic rejects. The second step is to mix the components together and heat them in a specialized furnace. Thirdly, the mixture is pressed using a hydraulic press to produce tiles, hexagon interlock, manhole covers and bricks. The whole process makes use of three pieces of equipment: the agglomerating machine, the furnace and the hydraulic press."

The process uses the REJECT plastics, plastics that would have ordinarily been sent to the dump! Again, from the description:

"Although plastic recycling contributes to a significant reduction of the waste in need of final disposal, it results in the utilization of only about 80 percent of the total quantity of plastics. We refer to the remaining 20 percent as the rejects of the rejects. Those 20% accounts for 13,200 ton/year of non-recyclable mixed plastic waste in Cairo (El Haggar et al, 2001) and they have traditionally been dumped in open dumpsites in the deserts, often burning up and producing noxious fumes........ In 2000, A.P.E. started a project to utilize the plastic rejects together with a sand mixture in the production of construction materials."

To put this in perspective, this was written in 2007, and the project started in '00, over a decade ago, in Egypt. American green builders love to crow about the techniques and developments made here in the US, and our "sustainable building methods," but the developments coming out of the "developing" and 3rd world have been largely ignored.

2 mil plastic bottles (amount used in USA every day)
via Savvy Housekeeping

But the potential here is vast. For people like me (ie, cheap and lazy), this seems to be a very interesting method of building using materials that no one wants, to create building materials that would be both useful and simple to make. And examining the techniques overall (particularly the heating and the hydraulic pressing), it appears this could be ideally suited for off-grid production, even potentially without electricity (a solar furnace wouldn't be terribly difficult to design once the specifics are known).

If anyone has any further info on how any of this works, I'd be delighted to hear from you. Otherwise, this is high on the list of projects to do once I return to the desert.