Car science: word on the streets
Hello! You're reading Car Science; please consider subscribing, it's free and helps me.
Hey,
Whoops, turns out I can't use the scheduler on Buttondown, so this did not go out! And neither did the Wednesday email! Or the following Friday! So much for being organised. I will, err, actually monitor this in future.
It's the first of the Friday(ish), research-themed editions of the newly rebooted and possibly improved Car Science. Unfortunately due to Everything the news editions are likely to be pretty much unremittingly heavy but these ones will be hopefully a little lighter, more hopeful and a chance to talk about some of the stuff that's just interesting.
Here's one: talking concrete. This is the sort of thing that comes up as a borderline silly news story about the same amount as it does as a serious one because it straddles the line of smart-anything being, more often than not, patently absurd and also some genuinely very important things about civil engineering.
The materials we use to construct pretty much everything come at a hideous carbon cost. Even just looking at the cement used to make concrete, every tonne comes at 900kg of CO2. That's about 88% of the carbon cost of the concrete as a whole, so that means an actual tonne of concrete is around 1022kg of CO2. That's probably lowballing it, too because that's just the composite of cement and stuff, not things like steel rebar to strengthen structural parts.
Concrete's amazing and it's fixed a lot of things, from housing to infrastructure but in the same way plastics have let us introduce incredible revolutions in hygiene and preservation, they're also a nightmare we're being buried under. Concrete's just bigger and heavier and a bit less obvious about it because you don't have a recycling bin option for it.
There are billions of tonnes of concrete in the world. In 2020, not a vintage year for producing anything, something north of 28 billion metric tonnes of concrete (reported as 14 billion metres cubed, which for standard concrete is between 2 and 2.6 tones per m3) was made. That's twenty eight trillion, six hundred and sixteen billion kilograms of CO2 which does make you question what's the fucking point of doing anything at all, otherwise, to mitigate climate change.
Total bleakness in the face of oncoming annihilation aside: if we can, somehow, reduce the amount of concrete we are using and especially the amount of concrete we're wasting then that's only a good thing.
Massive amounts of concrete are used in industrial settings and for constructing buildings, which this won't necessarily do anything about. But where the car bit of this comes in is that a lot of concrete is also used in constructing roads.
Road surfaces need repairs and maintenance and knowing whether you need to do that is a bit of a guessing game. If some bits look damaged then likely an entire chunk will be replaced, just to be sure because it's easier to do in one go than by piecemeal. Otherwise, you risk closing lanes or entire roads and causing tailbacks and jams only to have to do it all again a few months later.
Of course, any of us who've tried to use roads are probably pretty aware that happens anyway. But there's a genuine reason to not want to disrupt infrastructure; aside from pissing people off, it puts traffic at a standstill and creates unnecessary emissions. So you're working on concrete that cost a lot of CO2 to put in, with cars pumping CO2 out around you and while putting even more concrete down to really compound the issue.
Enter an invention from Purdue university professor and scientist Luna Lu. This isn't new research, I want to put right at the top here - she's been publishing about elements of it since 2017 but it is a technology that's gone from the lab stage through to actually being in production and getting ordered by a bunch of US highway boards who want in on it. That's interesting in terms of looking at the timeline of tech getting from lab to road and also pretty satisfying to see, for something that's as sensible as this.
Internet of things shit is mostly stupid. Why do I want my fridge to tweet or my home security system to be hackable? But an internet of infrastructure actually makes some significant amount of sense. Infrastructure is something it's genuinely useful to have real-time information about that the contents of my vegetable drawer is considerably less so. I mean, I know what's in there: my housemate's beer. Having more awareness of that wouldn't make me less annoyed about my wilting chard on the top shelf.
Anyway, domestic arrangements aside: concrete, as used in roads, is something it would be very useful to know more about, from the second its laid. How long concrete has been allowed to cure is a big factor in how durable it is; obviously, for a highway repair or build you want to leave it as long as possible but balancing the fact you also want to re-open a road. The temptation will always be to deal with the immediate and get the road open, even if that means doing the whole thing again in a few months time.
If there was a sensor that was saying "don't do that, I know it looks dry but it's not yet, leave it so you're not back here in a shittier season" then that'd be helpful from the get-go. This system, which has now been ordered by Indiana, Missouri, North Dakota, Kansas, California, Texas, Tennessee, Colorado and Utah to implement as a test on their concrete highways.
(If you're reading this from somewhere that isn't the US you might be going 'what the fuck is a concrete highway' but it's a relatively common road surface in America, with 20% of interstate links being concrete based)
There's a 2019 video featuring Lu and her research team fitting the sensors in a pilot project in Indiana (where Purdue is, although generally Indiana seems up for doing interesting shit with roads like charging pavements) and explaining the piezoelectric mechanic it uses to be able to assess the rigidity of the concrete around it, to a much greater extent than surface tools can and without having to drill into the concrete.
Piezoelectricity is an electrical response to pressure, which the sensor detects to work out how rigid the concrete is. Instead of it being based on predictions that don't always apply, given different environmental factors etc, it's easy to see exactly how ready for traffic the piece of highway is. Basically: road gets built better, lasts longer, doesn't need digging up as much.
Along with this, Lu and her team have also come up with a way to reduce the amount of cement used in the concrete mix. Cement manufacturing alone accounts for 8% of global carbon emissions, so cutting down on it is another environmental priority. Normally there's a demand that, in order to make more rigid concrete, there's a higher amount of cement in the mix but because this sensor can check the rigidity so accurately, you don't have to use victorian margins to guarantee a strong enough mix.
So there you go: talking highways, actually a good idea.
In other concrete chat, Wednesday's newsletter is about Ford's new electric pickup-specific facility it's building and optimising assembly lines in an era of rapid change. We are going to look at the robots picking up rabbits again, yes.
If you've got this far: I'm thinking about ways to monetise some bits of Car Science. Not because I'm like, the world's worst corporate ghoul just because I need money to pay rent innit. So I'd like to keep it completely optional and basically free forever but with the possibility of people chucking me some money if they want. I'm not gonna do it until I've got everything up and running and it won't be bombarding you with things but alongside getting some sponsors in, it's one way of paying for the stuff I pay for, like Buttondown, to make Car Science work.
(a few people asked me why I don't use Substack; it's because Substack host bigots like Graeme Linehan and I don't want to share a platform that hosts him but also cus it feels like Substack very much drives towards monetisation and I also don't really want to do that. Car Science has always been about writing the stories I used to pitch about scientific papers that got turned down)
Anyway, that's this edition. See you next week.
Hazel
x
Images:
Concrete buildings in Chiatura, Georgia (by me)
REBEL Concrete Strength Sensing System (via Purdue University)