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Transportation Science

Asphalt Additive Could Continuously Keep Roads Ice-Free (newatlas.com) 54

Posted by BeauHD from the would-you-look-at-that dept.
Scientists from China's Hebei University of Science and Technology have developed an ice-melting additive for asphalt that could remain active for years. New Atlas reports: [The researchers started] out by developing a chloride-free acetate-based salt. Such salts are considerably less environmentally harmful than chlorides, they're less corrosive to steel and other materials, plus they work at lower temperatures. The researchers proceeded to mix the salt with a surfactant, silicon dioxide, sodium bicarbonate and blast furnace slag (which has also been used in salt-proof concrete), resulting in a fine powder. Particles of that powder were then coated with a polymer solution, producing microcapsules. Finally, the scientists replaced some of the mineral filler in a conventional asphalt mixture with those capsules.

When the special asphalt was tested on the off-ramp of a highway, it was found not only to continuously melt the snow that fell upon it, but also to lower the freezing point of water from 0C (32F) down to -21C (-6F). What's more, based on lab tests, the researchers estimate that a 5-cm (2-in)-thick slab of the pavement would continue to release its salt capsules for seven to eight years, keeping the road clear that whole time. The study was recently published in the journal ACS Omega.
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Asphalt Additive Could Continuously Keep Roads Ice-Free More

Asphalt Additive Could Continuously Keep Roads Ice-Free

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  • Less harmful doesn't mean NOT harmful (Score:5, Interesting)

    by cuda13579 ( 1060440 ) on Saturday February 18, 2023 @05:38AM (#63303131)

    Especially when cars and the environment are going to be exposed 365 days a year.
    Oh...and it's encapsulated in polymers. So...for those that are concerned...more "micro plastics".

    I mean, I'm not a hardcore environmentalist...but, it seems like there are one or two issues being glossed over.

    • Polymer is not necessarily plastic, and looking at the paper it isn't in this instance.

    • Re: (Score:1)

      by Anonymous Coward

      Polymers and Plastics are not the same thing. A plastic is a polymer, but a polymer is not necessarily a plastic.

      "Complex carbohydrates," for example, are polymers. The octane in gasoline is a polymer. Your body is full of polymers.

      A polymer is just a chain of like molecules.

      • Your body is full of polymers.

        Indeed. DNA and RNA are polymers (of phosphorylated sugars, with "bases" as side-chains). Proteins are polymers, with various amino acids as the monomers.

        The octane in gasoline is a polymer.

        With what molecule as a monomer?

        Octanes are long chain molecules with a repetitive structure, agreed. But they're not polymers. A closer analogue would be the structure of "long chain fatty acids", which are long molecules (actually, trios of long molecules, hung off a triglyceride base, s

    • Less harmful doesn't mean NOT harmful

      Correct. Perfect is the enemy of good.

      Oh...and it's encapsulated in polymers. So...for those that are concerned...more "micro plastics".

      Actually, withe the scale they are working with it would be nano-plastics. What's interesting is that plastics on this level will break down relatively quickly in the natural environment, especially with UV exposure. The resiliency of plastics depends on being bonded with more plastic.

      I mean, I'm not a hardcore environmentalist...

      With your severely lacking knowledge of scientific processes and scaremongering, you would fit right in with most environmentalist groups.

      • Re: (Score:2)

        by hey! ( 33014 )

        What's interesting is that plastics on this level will break down relatively quickly in the natural environment, especially with UV exposure

        Yes, but into *what*? Where do those decomposition products go and what do they do?

        According to the paper, the plastic used is acrylonitrile styrene acrylate. This is a common thermoplastic used in building sidings, automotive parts, and 3D printing. It's decomposition products are acrylonitrile, styrene, and butyl acrylate. Of these butyl acrylate is probably close to completely biologically benign. Acrylonitrile and styrene are clearly not. Given the widespread use of this plastic it's certain that

        • What's interesting is that plastics on this level will break down relatively quickly in the natural environment, especially with UV exposure

          Yes, but into *what*? Where do those decomposition products go and what do they do?

          I think it's amusing you ask this of particular additive but haven't inquired about road or tire decomposition in general because they are all being shredded by the same mechanism: abrasion. It's also important to note that this isn't the first polymer let alone the first microplastic contributor because plastic makes up about 24% of the modern tire. I'm not a chemist, so i can't tell you exactly how ASA breaks down but I can tell you that if this is your biggest concern then you are missing the forest for

          • Re: (Score:2)

            by hey! ( 33014 )

            You seem to be fond of assuming people around you are ignorant. I am of course aware that road surfaces abrade, and that tire wear generates microplastic pollution. Neither of which has anything to do with whether this thing is a good idea, which it may be after some consideration and tweaking.

            Tire wear particle (TWP) research is still in its infancy; it's been a hot topic for several years and if you look at papers the research is still pretty crude. It's pretty much focusing on the establishing that TWP

            • You seem to be fond of assuming people around you are ignorant.

              Not really, your behavior simply reflected an apparent lack of awareness. I'm glad to read that you are up to speed.

              we don't really know much about what these compounds actually *do* in the environment, just that there's reason to be concerned.

              I'm not saying you shouldn't investigate or be concerned, I'm saying you shouldn't dismiss a less harmful solution because it's not a perfect solution. Perfect is the enemy of good.

              As for Greenpeace, if nuclear power were as profitable as, say, tobacco, Greenpeace would be just spitting into the wind.

              What you fail to acknowledge is that Greenpeace's effort are what makes it less profitable. A substantial part of the expense in building a nuclear plant isn't actually building it, it's dealing with frivolous lega

    • Indeed, the constant exposure to the material (instead of seasonal) and the fact that it only lasts "about 5 years" seem to be serious drawbacks - I would not want to re-surface a road every 5 years.

      I find it bad enough when they resurface roads every 15 years..

      • Indeed, the constant exposure to the material (instead of seasonal) and the fact that it only lasts "about 5 years" seem to be serious drawbacks - I would not want to re-surface a road every 5 years.

        I find it bad enough when they resurface roads every 15 years..

        Oomph - granted in China it's a bit different regarding liability, but if we started something like this, and didn't renew the roads every 5 years, there'd be hella liability.

        Another consideration - what effect does this have on traction? IIRC there were experiments with a similar technology some years ago. I looked for the paper a bit with no luck.

        It used Calcium chloride embedded in the asphalt. Yes, it kept the roads ice free, but it also eliminated traction about as well as Ice eliminates traction

      • I would not want to re-surface a road every 5 years.

        You must live in southern AZ. In colder areas, the roads don't last that long anyhow; drive through Glenwood Canyon sometime.

    • Oh...and it's encapsulated in polymers. So...for those that are concerned...more "micro plastics".

      This isn't anything new. All bitumen used for roads is finished and made suitable for the environment (temperature ranges) by adding a variety of polymers to it in different mixes depending on the purpose.

  • Plastic microcapsules that are released into the environment on purpose?

    • Re:Are you fucking nuts? (Score:5, Informative)

      by Malenfrant ( 781088 ) on Saturday February 18, 2023 @06:32AM (#63303183)
      Polymer, not plastic. Plastic is a subset of polymer, not a synonym. This is not plastic, and it's certainly not oil-based. It's a polymer made up of salt molecules that breaks down into ordinary salt molecules over a period of years.

      • Re:Are you fucking nuts? (Score:4, Informative)

        by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Saturday February 18, 2023 @06:36AM (#63303193) Homepage Journal

        TFS [acs.org][tudy] says that the polymer is styrene-acrylic-acrylate [safecosmetics.org] copolymer P.

        • Re:Are you fucking nuts? (Score:5, Informative)

          by Malenfrant ( 781088 ) on Saturday February 18, 2023 @06:53AM (#63303207)

          Which is only really dangerous when used in confined spaces, Again, used in plastic production but not actually plastic. As per the articles you linked, styrene-acrylic-acrylate is not considered harmful of itself but the styrene content may be. Styrene breaks down quickly. Exposure in e.g cosmetics is considered harmful because it's direct exposure before any chance of it breaking down, but in this use it's much less harmful because it breaks down in 1-2 days so no more chance of harm than any other road-covering material.

          All materials used in road surfacing are harmful to some degree. This is if anything less harmful than most of the particulate matter coming off roads because it breaks down faster. The posts on this about it being plastic and therefore harmful are misguided. The styrene-acrylic-acrylate is there to prevent it breaking down too quickly to be useful and is not harmful. It becomes harmful when it's broken down and releases the styrene but only for 1 or 2 days, much less than the rest of the particulate matter released from normal road use which is just as, if not more, harmful

          • If I were worried about acute medical problems in anyone, it would be the people who build the road.

          • Again, used in plastic production but not actually plastic.

            "Acrylonitrile styrene acrylate, also called acrylic styrene acrylonitrile, is an amorphous thermoplastic"

            Dunno man Sounds pretty plasticy.

            Also:

            "A plastic by the name of acrylates copolymer, on the label of several body wash, cosmetic and cleaning products, may be harming human health and the environment. Massey University Political Ecology Research Centre co-director Dr Trisia Farrelly said products containing acrylates copolymer carried health risks, yet they fell outside of the current microbead ban."

            "Th

          • Which is only really dangerous when used in confined spaces, Again, used in plastic production but not actually plastic.

            Under what definition says that styrene acrylate copolymer is not plastic?

            I mean - okay. Liquid styrene is not plastic. But maybe the wikipedia page on plastics should be corrected - styrene shows up there a lot. Can my confusion that styrene acrylate copolymer is not a plastic be resolved?

          • Which is only really dangerous when used in confined spaces...

            But is nonetheless not what you were attempting to claim until you were called out.

          • It should be worth noting that a large cocktail of polymers are used in bitumen for road production anyway. This isn't making the situation any worse than it already is.

  • +1 for global warming

  • Came for the FUD; wasn't disappointed (Score:3)

    by RogueWarrior65 ( 678876 ) on Saturday February 18, 2023 @09:40AM (#63303337)

    The moment I read this story, my immediate thought was that there was going to be some killjoy spouting off about potential environmental impact even though they have zero understanding of the whole thing (though they think they do) and I wasn't disappointed. What surprised me was how quickly that appeared. Some people have a knee-jerk reaction when it comes to something that would appear to affect the environment to the point of potentially killing off a great idea without ever really studying it. Tsk tsk, Chicken Littles.

    • Any environmental impact no matter how large (or in this case small) isn't going to stop technology. WE've been moving oil slicks and copper deposits for the entirity of our species. Making a human more comfortable and easing his or her physical burden in the short term will trump every other facet to human nature (see also: ego). Don't read too much into it.

    • The moment I read this story, my immediate thought was that there was going to be some killjoy spouting off about potential environmental impact even though they have zero understanding of the whole thing

      People often spout off on both sides of any issue with little to no understanding of the whole thing. And that tendency is not just confined to Slashdotters... it's humanity as a whole.

    • No, no, no...I'm way more concerned about it destroying my cars, than the environment.
      Sure, the roads are clear on snowy days...but on dry days, cars are dusted with it...on rainy days they're spattered with it.
      It's not suffering through a few applications of salt in the winter....it's exposure every day of the year, despite it supposedly being less corrosive.
      "Less corrosive" isn't "not corrosive".

      Regarding the polymers/plastics/not-plastics............it just seemed like it was going to be a very obvious a

    • If you look at a lot of scientific research papers of the last decade, especially medical, you'll see a lot of chinese articles. I think even last year the chinese had the highest amount of medical papers as the rest of the world combined.

      • Exactly. People need to get out of this mindset of the Chinese simply copying products created in the West. It still happens all the time, of course, but China is well on track to be the #1 country in R&D in every... single... industry.

        It's a numbers game, and their numbers keep getting better. They're going to be the economic superpower. It's inevitable, and it's coming sooner than most people expect.

  • ... put on tire chains. In addition to providing better grip on ice (and well below -6 C), they encourage drivers to drive slowly. And due to the insane bother of putting them on, they tend to make people think very carefully about whether this trip is really necessary.

    • ... put on tire chains.

      That is a frigging horrible idea for many reasons:
      a) Not everyone lives in Alaska, most people live in places where for a significant part of the year snow cover on roads is slight. So slight that it gets melted by a simple application of chloride.
      b) When you don't have thick snow / ice cover chains absolutely wreak both the underlying road as well as your tires.
      c) You need to have them, when you need them, and need to apply them which is non trivial for many road users.

      Leave the chains for people living i

      • Re: (Score:2)

        by PPH ( 736903 )

        That is a frigging horrible idea for many reasons:

        Yes, it is. And it underlines my statement about not driving when you don't have to. If it snows infrequently where you live, just wait it out. Stay off the roads.

    • I think you can be better off with tires like the blizzaks. I have one car with summer tires and have found the ability of rubber compounds vs temperature/surface to be very very different. My summer tires become ice skates around 40. Blizzaks on the other hand I hear stuff like this article. https://gearjunkie.com/motors/... [gearjunkie.com]
  • but roads aren't replaced every 7 or 8 years. Seems like a lot of effort and cost for a temporary solution. And how does that complicate snow plows putting down salt and sand? Would they need to keep track of which roads are still working and which are not? What happens when it gets close to end of life? Is it a gradual tapering of effectiveness or do you end up with clear patches and icy patches?

  • This reminds me of a previous scheme to make roads ice-free, back from the early days of nuclear power: Mix nuclear waste into the paving to cause them to be warm enough to melt the ice off.

    No, really! They actually thought about that until they had enough evidence on how dangerous radiation actually was.

    There was also one to make fluorescent lights with a little radioactive material, so you didn't need electricity. THAT one looked like it might have such low radiation outside the lamp that it would have

  • I wonder if it could be used in air entrained concrete as well as asphalt.

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