WEBVTT - What Are Those Black Squiggles on Roads?

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<v Speaker 1>Welcome to Brainstuff, a production of iHeartRadio. Hey Brainstuff Lauren

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<v Speaker 1>vogelbom Here. If you've spent a good amount of time

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<v Speaker 1>driving around the United States, especially in rural areas, you've

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<v Speaker 1>probably noticed those messy looking black squiggles that cut across

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<v Speaker 1>asphalt paved road surfaces and what looks like a paphazard

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<v Speaker 1>fashion at best. But arest assured they're not the wasteful

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<v Speaker 1>result of some sloppy tarwork, nor drizzles from your local

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<v Speaker 1>tar tankred transport. Instead, what you're noticing is crack ceiling.

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<v Speaker 1>It's a time honored technique for remedying damaged road surfaces

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<v Speaker 1>without inflicting more pain upon taxpayers by tearing up and

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<v Speaker 1>repaving the entire road and disrupting traffic while that work

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<v Speaker 1>is done. Asphalt is the sticky, binding liquid that sets

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<v Speaker 1>around the rocks and stuff that make up our road pavement.

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<v Speaker 1>That pavement can take a pounding from heavy traffic, for example,

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<v Speaker 1>or from the expansion and contraction that happens during seasonal

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<v Speaker 1>changes in temperature. Cracks develop when stress builds up the

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<v Speaker 1>surface layer of the pavement that exceeds its tensile strength.

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<v Speaker 1>Design and construction flaws such as an adequate drainage for

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<v Speaker 1>rainfall or a weak base underneath the road, can also

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<v Speaker 1>cause the surface to fail. Cracks are insidious because once

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<v Speaker 1>they appear, water can get in not just the cracks

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<v Speaker 1>but the base of the road and cause lots more

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<v Speaker 1>damage as it expands and contracts with the temperature. In

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<v Speaker 1>the arcane, highly technical world of road maintenance, there are

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<v Speaker 1>actually a lot of different types of cracking to contend with.

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<v Speaker 1>One of the most unsightly is fatigue cracking, a which

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<v Speaker 1>turns the highway into something resembling an alligator's hide and

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<v Speaker 1>which usually requires an extensive repair job. Another type of damage,

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<v Speaker 1>reflection cracking, results from movement between the road's asphalt and

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<v Speaker 1>concrete layers and looks more like a jagged gash. There's

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<v Speaker 1>also edge cracking, in which rows of wavy, curved cracks

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<v Speaker 1>parallel the road shoulder. If you've tried to build a

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<v Speaker 1>nice new road every time that stuff happened, it would

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<v Speaker 1>be prohibitively expensive. In introduction to crack ceiling, a two

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<v Speaker 1>thousand and eight treatise on the subject from the Texas

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<v Speaker 1>Engineering Extension Service at Texas A and M University, the

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<v Speaker 1>experts note to that ceiling cracks is way cheaper, about

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<v Speaker 1>two thousand, five hundred bucks per mile of road compared

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<v Speaker 1>to sixty thousand dollars for putting down an overlay surface,

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<v Speaker 1>though of course two thousand and eight was a while ago.

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<v Speaker 1>In twenty sixteen, the city of Littleton, Colorado, estimated that

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<v Speaker 1>crack ceiling cost about five thousand, five hundred dollars per

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<v Speaker 1>laane mile, while overlaying cost approximately three hundred and twenty

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<v Speaker 1>thousand dollars per laane mile. Trick friends a mile is

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<v Speaker 1>about one point six kilometers. These seals aren't actually made

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<v Speaker 1>of tar these days, it's more likely to be some

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<v Speaker 1>sort of high performance polymer asphalt mix designed to form

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<v Speaker 1>a bond that's flexible enough to move with the road

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<v Speaker 1>and keep the crack from growing. A cruise apply it

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<v Speaker 1>to the fissures with a device that looks vaguely like

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<v Speaker 1>a vacuum hose working in reverse. However, although crack ceiling

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<v Speaker 1>can keep a road from deteriorating further, it doesn't make

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<v Speaker 1>the road any smoother. You might not feel it in

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<v Speaker 1>a smooth riding sedan or suv, but some motorcyclists call

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<v Speaker 1>the patches tar snakes and contends that they cause damage

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<v Speaker 1>to bikes or even accidents. Today's episode is based on

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<v Speaker 1>the article what are those wiggles of tar on the

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<v Speaker 1>road on howstufforks dot com written by Patrick J. Kiger.

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<v Speaker 1>Brainstuff is production by Heart Radio in partnership with HowStuffWorks

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<v Speaker 1>dot Com and is produced by Tyler Klang. Four more

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<v Speaker 1>podcasts from my heart Radio, visit the iHeartRadio app, Apple Podcasts,

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