This take seems trivially and obviously wrong. Recycling plastic produces a lot of nasty chemicals and is awful for the environment, but we still do it, because the alternative (chucking it in a landfill) is worse. The question is not whether these plastic bricks are bad in absolute terms, it is whether they're worse than whatever was being done with Kenya's plastic waste before this woman came along.

However, it is curiously common. From elsewhere in this thread:

> What about leaching [sic] chemicals into the soil and groundwater?

> I do wonder about microplastics flaking off of them, though....

> ...making me concerned about plastic particulate being released...

> What happens when these erode - wouldn’t plastic particles contaminate water?

> ...how does this product not heavily pollute the environment?

Isn't that interesting? Not to sound preachy, but did anyone have the "wait isn't this bad for the environment" reaction to any of the other stories on HN today? Starlink? That new Samsung fab plant? Shit, there's an ad on the front page right now for a gourmet dinner delivery startup. What is it about this one that brings out HN's inner environmentalist?

This is one aspect of the tech world (and more broadly the "comfortable knowledge worker" class) that irritates me. There are so many aspects of sustainable development that are only considered from a perspective of NIMBYism mixed with orientalism. The one that bothers me the most is the portrayal of overpopulation as something caused only by people in developing countries, as if the first world wasn't part of the total count.

FWIW if you ignore immigration, nearly all first world countries are gradually depopulating. https://en.wikipedia.org/wiki/Sub-replacement_fertility

Of course, that doesn't mean for a second that the solution to the world's problems somehow involves population control in developing countries.

So the solution is probably to help them develop ASAP.

There are two kinds of mythologies that have been the cause of reckless and thoughtless procreation leading to overpopulation: 1. Religion 2. ‘Abundance’ mythologies penned by the Peter Diamandis/Steven Kotler ilk.

Regarding "religion": do you think "religions" came up with the concept of having a lot of children?

You don't think it's simply a natural instinct, like in all other animals? And that in a world where few make it to adulthood, people tried to have more children?

It's pretty well-established that it isn't poverty per se but gender equality that predicts birth rates.

Here is a blog post of the author in case the above is not readable for you: https://www.niussp.org/article/gender-equality-and-fertility...

This study is in the context of previous assumptions of a U-curved relationship: low equality == high birth rates, medium equality == low birth rates, high equality == high birth rates. That study shows that the last part doesn't seem to be true.

The macro trend of poverty <> birth rates points in the opposite direction: https://en.wikipedia.org/wiki/Income_and_fertility

Data points on the very poor end are all over the place, though.

The high workforce participation -> low birth rate correlation is definitely visible over time: https://ourworldindata.org/grapher/fertility-and-female-labo...

Why not? A lot of people on the left are saying that having children is bad for the environment, why shouldn't this be true in poor countries?

Fewer children is better for the environment; that doesn't mean one has to favor population control. It's easier, more democratic and probably at least as effective to enforce equality for women in education and economics, and the lower birthrates follow automatically.

Not that there's anything particularly democratic about "enforcing equality" in foreign countries.

That would be wonderful because it would mean that workers get fair wages. Lack of productivity can be compensated by automation.

>How do you reverse it when it becomes a problem?

That's biologically impossible. Even if you sterilize every human with a birth certificate on earth.

Of course, this is the average American, which is a deceptive number when talking about countries with high levels of wealth inequality.

https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...

I’m not an advocate for population control, but if I were I wouldn’t exclude poor countries from my scope. Many poor countries are “developing” and it seems more reasonable to ask people that were planning to have 8 children to instead have 4 rather than targeting people that were aiming for one or two. Especially when the 8 kid family to be is already poor.

As this article [3] (unfortunately not in English) aptly puts it: "Air travels represents around 5% of the emissions of humanity [4], but 90% of humans have never taken a plane." (the 90% figure is arguably difficult to assess [5]. It comes from an article in French behind a paywall, but other sources [6] show similar numbers).

Finally, CO2 is of course not the only source of pollution. But this map [7] showing meat supply per person shows a similar direction.

[1] https://upload.wikimedia.org/wikipedia/commons/a/a7/CO2_emis...

[2] https://www.gapminder.org/tools/#$state$time$value=2014;&mar...

[3] https://medium.com/enquetes-ecosophiques/d%C3%A9mographie-et...

[4] https://core.ac.uk/download/pdf/30987495.pdf

[5] https://www.quora.com/What-percent-of-the-worlds-population-...

[6] https://www.theguardian.com/business/2020/nov/17/people-caus...

[7] https://upload.wikimedia.org/wikipedia/commons/e/ed/Meat_sup...

The rest of the world is catching up faster than most people are aware.

Here's a link for daily plastic waste generation per person: https://ourworldindata.org/grapher/plastic-waste-per-capita

I don't see an obvious correlation between first world and amount of waste: the #1 country is Guyana, China and Russia are well above Canada, etc.

Similar with CO2 emissions: https://www.worldometers.info/co2-emissions/co2-emissions-pe... The #1 is Qatar, we in Montenegro are on the second place.

I'd like to see a period in which China, India, and smaller nations are able to use more than their share of the global quota while the wealthier countries in western Europe and North America use less, per capita and in sum.

I don't think this is obviously wrong at all. Dispersing a fine mist of micro plastics into the environment, where it can enter the air and water system, is very very different than sticking a piece of plastic into the ground, where it will comfortably sit for a thousand years with minimal decomposition.

For a good example, here's [1] a study about how car tires, which slowly disappear into the environment, are a major contributor to micro plastics in the ocean.

[1] https://www.nationalgeographic.com/environment/2019/09/tires...

Huh? I don't see anything in the article to suggest this is happening...?

Similarly, if rain is expected, I don’t need the forecast to tell me that rain makes clothes wet.

That's the thing - does it actually decompose at the same rate or slower than eg. concrete or brick?

The rate of decomposition is not the correct metric to look at, in this context.

Obviously many things not done for environmental reasons have environmental impacts, but the mere idea itself doesn't automatically invoke that perspective. You can read about a new fab without thinking about the environmental aspects, but you probably cannot read about somebody recycling plastic without thinking about the environment.

Thanks for bringing this up: Honestly, that thought has never crossed my mind when thinking about these initiatives. Much appreciated: You've changed the way I think.

Because the project is literally about plastic pollution solving?

Plastic is so cheap any recycling project faces either an environmental or an economical showstopper. I am glad this one is having some impact.

Iirc, plastic wastes are added to the tar mix to cover roads, to saw dust and glue to produce composite deck boards, etc. I am not informed enough to have an opinion on whether it’s a good or bad thing.

So yeah, any form of reuse/recycling seems better than that.

Traditional bricks first appeared in China and have been adopted and used by humans across various civilizations for thousands of years.

As engineering advanced globally, the pros and cons of bricks have been well explored and well understood. Plastic bricks are a new contender to this problem.

That said, when you have a new contender to a centuries established and globally adopted solution, it might be more likely to prompt exploration of its potential cons.

Starlink is a new engineering solution with several of its own cons that have been reported in HN. It is difficult to compare Starlink against other alternatives when Starlink has a narrow use case that it particularly excels in (high speed Internet to unserviced areas of the globe)

If the starlink article involved how much plastic waste they caused the discussion would be around that, if it involved privacy and surveillance we would talk about that, if it involved how fast the speeds are we would talk about that...

Manority of plastic waste is NEVER recycled. Lets not spread myths.

"Officially, Japan recycles 84 percent of the plastic it collects, one of the highest rates in the world, but the government designates three types of recycling processes: material, chemical and thermal. Material recycling means the plastic itself is reprocessed into new plastic — PET bottles, for instance, are made into new PET products. This is probably the image of recycling that most people have. Chemical recycling means that plastic waste is broken down into its constituent components, which are then recombined to make new plastic materials. Thermal recycling means that the plastic is burned in incinerators to produce energy."

https://www.japantimes.co.jp/news/2019/07/06/national/media-...

Incidentally, in Japan, PET recycling is a very small minority of all plastic collected, so it hardly moves the mark even if that part is recycled in plastic-loving Japan.

The others aren't claiming to be an environmental solution so it doesn't get looked at under that lens first. Plastic as well strikes a nerve by hitting upon other issues like microplastics and past deception of recyclability.

I think it essentially hits a lot of "bad idea flags" combined with a cognitive bias I noticed. A company which casts itself as "pro-worker" company paying $12/hr for say sign-turner jobs when most in the field/area pay only minimum wage getting more backlash than everyone else. didn't "betray them" in spite of paying higher than everyone else. It seems everybody hates hypocrisy in which they are not a participant.

Quite the opposite actually. Tires are already a huge source of microplastics pollution. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5664766/

> because the alternative (chucking it in a landfill) is worse.

The problem is that landfills aren't living up to their names. They aren't being filled in and buried. Burying plastic is the best thing you can do to dispose of it. It's only when they're left in the open air to break down and be spread all over the oceans by wind that you have a problem.

Is it, though? Or was that just a scam to keep us buying plastic shit and to keep packaging unregulated?

It is not trivially and obviously wrong that it might be better to throw plastic into big holes than to spread it all over the surface of the planet. It's not true for nuclear waste. Not to be preachy, but the "at least they're doing something" common sense argument is not good. You have to do the math.

How so?

There is a lot of demand to be told that when you separate your plastic out, it gets recycled. There's no demand for the recycling to actually happen, so mostly it doesn't.

Why is that worse?

Plastic is made out of oil. It belongs in the ground.

"Former data analyst and engineer creates startup to develop award-winning material over five times stronger than concrete from waste, following scholarship in US university materials lab."

This is the oldest internet comment phenomena in the world, so why do you only notice it here and not every other time?

People always have the nature to attack and knock down, and stories of an individual building something on their own is a far more accessible punching bag than anything else you mentioned. We get to roleplay as critics, scientists, environmentalists, bureaucrats, and we love it.

pg's "middlebrow dismissal" was coined from watching HNers attack the guy building something in his garage.

This is obvious and very easy to see, while the other examples you brought up aren't. Your examples might even be doing more damage, but because the end result is shiny, people are distracted.

Plus, I'm sure there's a part of first world vs third world prejudice: "she's probably uneducated and doesn't know what she's doing, plus her accent sounds that way".

Buy yes, I came to say something similar, if you just compress the plastic into a block and lay it down to make a path then as it deteriorates surly you are just contaminating your environment with mico-plastic particles.

The article says that the plastic is mixed with sand, heated, and then compressed into bricks. Given this, is your comment still valid? Honest question, I'm not a material science person.

People prefer to distribute their problem into invisible pieces put into the environment slowly over 1000 years than to just bite the bullet and incinerate plastics that have reached their usable lifespan...

Delaying some of the carbon we put in the atmosphere for hundreds of years is massively useful, because it buys us time to try stave off and ameliorate some of the effects of climate change.

Burying the compressed bricks is actually a great way to handle sequestration.

[1] https://www.npr.org/2020/09/11/897692090/how-big-oil-misled-...

A plastic paver walk way is nicer than a muddy path littered with plastic refuse.

For instance, the issue with flammability/melting and also microplastics contamination is real and worth asking. I wonder if using these bricks as building foundations or something might not be a good way of solving both problems at once. However, that's an idea that would only arise if we ask pressing questions in the first place.

From their perspective it is a good use of something that might otherwise be litter.

I've always wondered if they couldn't compress it, like those bricks but cubes, then use those cubes mixed with base fill dirt for building bridges and such. Like the massive earthworks they build around highways and such.

Now with the unknown prospect of increased weapons development over a century, it gets even less ridiculous. Imagine the international quagmire where something worse than nukes exists, but with a much easier manufacturing process.

In any case, my exact argument isn't that extinction is the most likely scenario. Just that the least likely is one where we are just chugging along with the same overall technological capabilities. Worrying about what will happen to micro-plastics in a hundred years is like a New Yorker worrying about the growing quantity of horse manure in the city circa 1894.

I am pretty sure that, even if not "forever chemical", the plastic dust will outlive your lungs.

Though it probably does depend on the type of plastic, but I'm no chemist.

I don't expect this to be heavily processed. More like melted together with some additions.

I think another interesting point to consider is cost. I watched a video a while back about a premise of using plastics for building roads, and in addition to the deformation/UV deterioration issues being brought up, another issue that was brought up was that concrete is cheaper than even the lowest quality recycled plastic.

In the first world, brick construction is extremely expensive and you're right -- modern residences are often built with structural beams (whether wood or steel), and the brick is usually just a veneer.

But in the third world, variants of brick (e.g. cinder block) are often the norm, and are structurally load-bearing, and work fine for two to three stories. And they're very easy and cheap to build with.

The US has a ton of cheap lumber so load-bearing wood frames are common. Many countries don't have forests like that so bricks/blocks are the way to go.

Bricks are quite common in Europe, at least for buildings up to a certain height. The resulting buildings here (in Germany) offer higher living quality with better thermal and acoustic insulation than a typical North American beams + drywalls building. That's just an observation though and maybe the general construction method is not the cause - maybe it's just because our windows and doors are much more solid.

Also... what does "much more solid" windows mean exactly? Like, are you saying European window glass is... thicker or something? Which wouldn't make any sense, and I'm not even sure what a benefit would be?

Unless someone has some actual comparative statistics, the idea that European windows are somehow more "solid" than North American ones isn't at all obvious. I've spent years living on both continents and never noticed a huge difference. What matters the most is simply the age of and investment in the building, not which continent you're on.

[1] https://www.dwmmag.com/survey-multi-pane-windows-now-on-59-p...

Even 80-90 years ago, brick housing in wester Europe was made with walls of two layers with an air/insulation cavity inbetween. Current practices usually don't use clay bricks but aerated concrete [1] which has great thermal insulation, plus insulation layers on top.

> what does "much more solid" windows mean exactly

Triple-glazed windows with well-insulated frames, rather than single-pane push-up windows that leak heat like a sieve. Massive difference in thermal and acoustic insulation.

[1] https://en.wikipedia.org/wiki/Autoclaved_aerated_concrete

A standard two-cell "cinder block" in the US weighs around 17.5kg and costs around $2.00 at home depot [1]. I suspect they'll be much cheaper in bulk. Maybe $1.50 if you buy thousands?

The same thing costs ₹65 INR in India [2]. Or about $0.89 (₹73 INR = $1 USD). Not sure if they would accept orders for a single block at that site.

So, more expensive in the US. But not extremely so.

[1] https://www.homedepot.com/p/16-in-x-8-in-x-8-in-Normal-Weigh... [2] https://www.indiamart.com/proddetail/concrete-hollow-blocks-...

Bricklaying requires much more labor than wooden frame construction. And it requires more skill which most contractors do not have.

It's more expensive for these basic economic reasons.

https://theconstructor.org/construction/masonry/load-bearing...

Bricks are decorative in a few buildings, but this is by far the minority.

Where bricks are used in < 8 floor high buildings, they normally are supporting the weight of the entire structure.

But if this is a house, expected to last 150 years plus, and you're already bringing lots of bricks to the site, you really ought to be using the bricks to hold the building up and reserving the wood for the internal floors and other things that will be replaced every 75 years.

https://en.wikipedia.org/wiki/H%C5%8Dry%C5%AB-ji

Wood easily lasts 200+ years as long as it’s thick and dry. It tends to sag over time, but most buildings end up being fairly temporary on those timescales.

If there is a special case where tensile forces are expected, for example a retaining wall, or a mid-rise structure, or earthquake load, the engineer will specify the the masonry is reinforced with steel and then it can resist tension through the unit/mortar interface just fine.

It is a poor structural engineer who tells the architect masonry isn't an option because tension.

I don’t know what structural engineering you’ve done or what jurisdiction it’s in, but for practical purposes on the west coast in America, structural masonry isn’t an option beyond maybe 3 stories because of tension (due to seismic demand) and any structural engineer that says otherwise is looking to get sued for negligence.

Elsewhere in America this is less true but still most modern engineering doctrines would lead you quickly away from masonry for anything substantial, although cost and schedule is obviously a key factor in masonry’s favor.

Everything else about the use of masonry in walls I generally agree with, although the move away from allowable stress has impacted it as described above. Except maybe I would quibble about the use for retaining walls. CMU can be particularly cost effective for some geometries of retaining walls when used with steel.

This house is going to outlive me as well, barring a natural disaster (which it is better suited to withstand than a masonry home, given that my most likely disaster is an earthquake).

When US action movies started to show up more in Poland, many people joked how american movies exaggerate things by using cheap plywood scene sets for houses. Finding out that american homes are actually built like that was a bit of a shock to many.

We reserve 220 volt outlets and higher voltages (3 phase 480, etc) for the larger loads, and those plugs are huge, and not something found in a typical home.

2 times less voltage === 4 times more heating for the same resistance (heating is calculated from R times I^2).

This means that short circuits, wiring problems are potentially much dangerous.

In cities, almost all buildings older than 1950 are also made from bricks.

Wooden structures copied from Scandinavia are slowly coming into fashion for smaller family houses (the construction process is very fast compared to bricks), but they are still very much in minority.

Taller constructions are concrete + steel.

There have been some advancements in wood for taller structures in recent years. Basically they have come up with wood that is as strong as concrete.

Main problem is fire/pests/rot/etc so you can't build crazy big but there are now 7 or 8 story tall apartment buildings made out of wood mainly in Helsinki for example.

Making apartment buildings out of wood is also much more environment friendly then concrete (somewhere around 50% less total co2)

I saw this in an excellent exhibit at the National Building Museum in DC a couple of years back. Will try to track down a reference.

Some discussion (and dead links) near the bottom of this thread - https://news.ycombinator.com/item?id=16331375

I have also lived in buildings that had steel or wood beams in walls for the purpose of keeping the wall rigid (so that it doesn't buckle), but the bricks were still holding most of the load.

Even where a timber frame bearing roof and floor loads exists so wall bricks just "fill space", they have to be sufficiently performant under compression to support the weight of brick courses above them.

These bricks will probably work fine as foot paths, the sand and dye in them will slow UV degradation and foot traffic is unlikely to wear them much. I wouldn’t build a house out of them, offgassing would be a bigger concern for me than sagging, at least on a 1 story structure. A brick is a widely useful thing so I hope her business does well. She’s essentially just making plastic composite which is something you’re seeing in North America now used for decking.

This is what happens when you use polyethylene as part of your building: https://www.bbc.com/news/uk-40301289

A non-flammable coating would perhaps be a layer of plaster or paint?

I think you are seriously overestimating the flammability of the product. Have you seen rooms with vinyl floors, PVC windows, foam / fake leather couches? Each of those will burn more easily a viciously than the bricks.

My concern would be with possible structural failure at high temperatures and some fires may be able to pass through walls of these bricks. However, I don't think they are building apartment buildings from these bricks.

I am not a materials engineer, but it looks to me that bricks with more than 10% of polyethylene are likely to be flammable in the case of a house fire.

I don’t know whether the Grenfell tower cladding had filler, but it is common for the polyethylene core to be mixed with filler within the cladding to help protect against fire, for example the ALPOLIC A2 product mentioned in [1] has an image showing a table with:

ALPOLIC fr: Combustible ingredients < 30%. < 13 MJ/kg

ALPOLIC A2: Combustible ingredients < 10%. < 3 MJ/kg

And [1] says “Its calorific value is given as something less than 13 MJ/kg, more than four times the value considered to be of ‘limited combustibility’ in the UK”.

Above facts are why I think even a large percentage of sand might still leave flammable bricks (polyethylene is like solid petroleum, until it melts and behaves more like a liquid or wax with a viscosity depending on multiple factors).

[1] http://theriveroflife.com/2018/02/08/grenfell-tower-is-the-c...

You need space shuttle aerogel tiles not paint.

Sand has a lot of thermal mass, so with some insulation against surface fires (PE surface is easy to ignite) - say a proper coat of paint, or maybe some plaster - a lone kindling would not ignite the bricks. A proper fire will, but then you should be running away anyhow.

Still, if I were a firefighter, I would not approve of such building materials, unless the shoddy construction is well known, so noone dares go inside, mainly because it's likely to collapse and turn in to a bunch of hot burning goo. Luckily, they seem to use it for pavement.

again, far before a fire reaches a point where it's widespread the heat of the gasses created by a small fire are already 4x what these bricks can stand before the binder involves melt.

So long before you're worried about thermal mass, there would be nothing holding these bricks together and you have a mass of loose sand and melted plastic.

You could paint it with intumescent paint but I doubt it would be effective given the low melting temperature, and would probably end up costing as much or more as the brick.

If unconvinced, try the same with a piece of old sofa, fake leather or vinyl flooring (with or without paint).

I don't think you're listening to what I'm saying about the common air temperature around small fires (auto-ignition of hot gasses at ~600°C is common) and the melting temperature of the binder in these bricks (150°C max).

It's not about ignition of the PE, its about cohesion of the brick PE binder (and thus the sand) at higher temperatures. Your painting this brick that will lose cohesion will do exactly nothing for the performance of the brick.

I dare you to think about it critically, instead of making useless dares that don't address what the other person is saying.

I mean, yes, it's nowhere near western building codes, and if there is a non-trivial fire, you need to get out, fast. Much faster than with most typical building materials, though the bricks won't come loose instantly, and that has to do with thermal mass, conductivity, temperature and amount of heat.

Note, a match will not do, if painted. A blast furnace will, but I do not see the relevance.

Yes, I may have overestimated how much fire the bricks might survive, in my first comment, but I'm not saying the building would withstand a fire - the main point is, that it's more resistant than EPS cladding, couches and PVC flooring, so not as dangerous as it might seem.

https://gjenge.co.ke/our-products/

The end of the article says they founded in 2017 and have recycled 20 tons of waste. Maybe structural issues will emerge after 5+ years of use but it sounds like this approach has already had a fair amount of real-world usage.

By definition something plastic will deform, else it wouldn't be plastic! A "rigid plastic" would be like a "miniature giant"

In their usable form plastics have varying modes of failure depending on their material properties, many of them do not deform at all under stress but rather shatter just like glass.

Vast majority of "plastics" are plastic in physical sense. But some are not. Some undergo physical or chemical change after they are cooled and are on longer plastic in the physical sense.

So maybe not "by definition".

Bricks with plastic binder aren’t perfect; leachate and durability under load and abrasion are issues to be aware of.

But the alternative and predominant plastic disposal method in this and similar contexts is dumping in a ditch, in a field or in an unsealed ad hoc landfill at best, or more probably burning in a heap with whatever fallen leaves and other garbage there is that’s remotely flammable. Which results in a toxic chemical smog that persistently contaminates the air, soil and water.

And even if they were using melty thermoplastics, the properties will still change drastically the moment you introduce a substrate like sand or gravel and turn it into a composite. Just like how there is a massive difference between pure Portland cement (extremely brittle, with almost no load-bearing capability) and concrete, which is a composite. Nobody seems to regurgitate these rubbish misconceptions about plastic when talking about carbon fiber composites (which are held together by plastic!).

I don't think I'll ever understand the techie's tendency to think they know more about certain fields than specialists that work in those fields.

As for being a "horrible idea", this is what happens to plastic today in the slums of Nairobi:

https://media.gettyimages.com/photos/kibera-slum-nairobi-pic...

Even if the bricks leach a bit, it's still much better than the status quo of soaking individual plastic bags in sewage for years.

Yeah, it can get hot in parts of Kenya. But this is in Nairobi, which is somewhat elevated, and doesn't get too hot at all.

I for one can appreciate that someone is taking effort to resuse/recycle plastic trash into something useful like this. Maybe rather than shitting all over something for a use it's not necessarily intended for, maybe try to think of other uses this kind of innovative processing can be improved would be much more productive.

I'd sure as hell rather know if my home is going to collapse if I build them out of plastic bricks than someone telling me all of the things I could have used them for instead.

Just don't claim it is "stronger" than regular brick if that is not true.

Not a very constructive response. Do you have any counterpoints to the other user's points, or do you just not allow people to point out potential issues with materials that may be used for human housing? Progress requires a balance between some people focusing on achievements and some pointing out the things that can still be improved. If I were going to rely on a new material, I'd definitely want its issues to be pointed out and addressed first, rather than just jump to using it.

You’d want that negativity problem to point pointed out and addressed, wouldn’t you?