The World's Most Recycled Material

Exploring the complexities that go into the creation and application of asphalt concrete.
Of all the ubiquitous things in our environment, roads are probably one of the least noticed. Our roads see tremendous volumes of traffic and withstand considerable variations in weather and climate, and they do it on a pretty tight budget. That’s really only possible because of all the scientists, engineers, contractors, and public works crews keeping up with this simple but incredible material called asphalt.
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-Patreon: / practicalengineering
-Website: practical.engineering
Writing/Editing/Production: Grady Hillhouse
Editing and Direction Help: Wesley Crump
This video is sponsored by HelloFresh.

[@PracticalEngineeringChannel]

👷 Enjoying the series on roadways? More are coming! Subscribe to follow along: practical.engineering/email-list 🥝 Get $80 off of your first HelloFresh box at bit.ly/30sYo7c

[@Erik_coolman]

Nice

[@thisrecordingsessiontm3633]

Nice

[@jessewalters7046]

Great video. I'm curious environmentally what the impacts of asphalt is on surrounding soil. I have a recycled asphalt driveway, and it's ~100 feet from my well. Being a petroleum product and it's usage world wide is pervasive, what environmental effects have their been observed in soil quality or contamination?

[@raystinger6261]

All those clips you use on your videos (like the trucks carrying houses or ducks crossing the road), where do you get those? Do you film any of those yourself?

[@mrss649]

Please Notice Me!!!

[@CKOD]

"The average person makes several trips to various places on a given day" Whoa now, easy with that 2019 thinking.

[@alex0589]

CKOD yeah i think he prerecorded these in 2015 then closed the hatch on his bunker....(??)

[@ethanhsu8596]

Yeah, now I make several trips down the stairs, and let me tell you how HARD that is: I have to stop eating popcorn, get off the couch, and actually walk 😭 😂

[@yetinother]

Just get a job in construction, they never stopped for covid, you will be out in the sun getting heat stroke and breaking your back in no time at all!

[@chipskylark5500]

Retail has lots of available jobs too if you're feeling lucky :)

[@Batman6544]

Hhhhhhhhh

[@God7odTaxationIsTheft]

One of life’s pleasures is traveling on a fresh paved road.

[@someoneelse7629]

...with a motorcycle... it makes it even better...

[@vinnygi]

Yeah. You only have about 2 days before the potholes appear.

[@uniworkhorse]

Ahhh, nothing like cruising on a nice bike down a fresh road

[@Sabi1234567890Asdf]

How so. You like that smell????

[@supermegadisappointment7424]

It’s really good if you live in Michigan

[@TomsLife9]

"how much traffic do you expect?" New Jersey: ALL OF IT

[@shawnr771]

In Dallas in the 1950s the engineers who designed North Central Expressway said that when opened the road would handle 80,000 cars per week. 80,000 cars went down it the first day. It took 40 years of political machinations before it was rebuilt. And traffic still stops on Thursday for the Friday afternoon rush hour.

[@iHeartManii]

I have you a notification dude

[@ronkoestlinger1172]

You live in Jersey? Which exit?

[@shawnr771]

@@ronkoestlinger1172 does it matter?

[@allwinds3786]

In the early eighties a friend who worked as a chemical engineer for the Illinois Tollway Authority. He was asked to create a asphalt binder that would last 5-8 years (presumably so they could justify the tolls). He said he could design chemistry to withstand decades in the Chicago area but that's not what they wanted.

[@Thatguy-mo8jd]

Those unions 😂

[@kylehammond8091]

I live in the Chicagoland area and you’re not wrong. Also the big wigs can go 🤬 themselves. Illinois (Chicago specifically, is garbage.)

[@yuanruichen2564]

planned obsolescence

[@amols101]

Devil's advocate. If they go out of business, there would be no one left to build the next road or the next highway. Also, the longer lasting ones probably cost more as well.

[@willmcconnell6008]

To everyone "debating" the level of detail in this video. He is using plain english to introduce you to a complex topic/industry so the general public can have a better **basic** understanding of what goes into the engineering of roads. The point of many of his videos is just to give you a bit to interest you and for you to look up more on your own. Even if things were generalized to a point they aren't 100% true, he gave an excellent highlight of information about the topic that people devote years of their life to. Making complex things simple enough for the average person is not easy and I respect him a lot for taking the time and energy to do so.

[@sfmc3000]

Cement must be heated to 1000 degrees centigrade and more ! Usually using coal in n order to manufacture the cement And f course using bitumen which is a leftover from oil refining and is another toxic substance we put in our roads and then the rain washes it into the soils and groundwater- just like Plastics is leftover gunk from the oil industry and this ends up in our waterways and oceans we make all of these so that cars which use even more CO2 in their manufacture and pump more CO2 when we run them. -- We should have stuck with the electric cars in the towns and suburbs and great train service to go from city to City as we used to do. . We had electric cars at the beginning of the century and there were over 15 thousand electric car charging stations in New York City over 100 years ago can you believe that?

[@willmcconnell6008]

@@sfmc3000 Great points about the environmental impact of asphalt. And yeah we definitely should've kept working with the electric cars. Who knows where we would be today if big business kept investing in the R&D. Maybe John B. Goodenough could've been working on solid state batteries much sooner.

[@hedgehog3180]

Also it seems like this is like his series on cement so this is just the introduction to asphalt and then in later videos he'll have practical experiments and such to get more indepth (which we saw footage of).

[@stevenmobley5882]

I get what the point of his videos is, but would have still liked him to mention the voc's that the asphalt/bitumen give off. This is another form of aging in asphaltic cement pavements that has to be addressed when recycling them. The more oxidized the binder gets, the stiffer it typically gets. This is one mechanism of asphalt shingles getting hard and stiff over time. It is extremely recyclable though and often just requires adding a lighter portion of oil refinery products to thin it back out and make it flexible and sticky again.

[@stevenmobley5882]

@@sfmc3000 both Concrete and Asphalt pavements take energy to produce, but they save incredible amounts of energy by allowing cars to travel them more efficiently than a dirt or gravel road. Trains ride on steel rails which are energy intensive to produce. Those rails ride on either concrete ties or wood ties soaked/coated in all manner of toxic preservatives. You kind of have to take your pick on what level of environmental footprint you are comfortable with.

[@stevemattero1471]

Ever so slowly, this series is making me less pissed about road repairs

[@StrokeMahEgo]

This channel sponsored by Big Road

[@722Moo]

Civil engineering a solid major

[@madjack1748]

Roads don't magically appear out of thin air.

[@chaotickreg7024]

@@madjack1748 I mean, if you accidentally step on grass enough times then you could make a road.

[@Darkrider8893]

I can make you pissed about it again. Like the fact that companies purposely take their time to get the most money, or the fact that the government takes a couple hours to check the road before the crew can continue. The most irritating is that companies charge the government more for the same materials they sell to everyone else.

[@jameswood5832]

"We also drive heavier trucks than we used to" Ahh yes...those light weight roman trucks.

[@Viper-dn8ix]

Like he said "They don't build 'em like they used to" lol

[@davelawson2564]

Cement roads are best and last 100 - 200 years depending how its built. If not romans would have built with worthless asphalt roads that break apart after 1 -3 years and at best after 10-12 years. Petroleum industry funds fake "studies" to run down Concrete roads so they can keep making asphalt sales/roads every few years. Cost difference isn't much. Even if its 200% more the long life span makes the annual cost 3 times more for asphalt. If all roads were built with concrete roads the country could have saved trillions in wasteful asphalt road building racket and most road builders would have to look for other jobs or unemployed.

[@Teporame]

@@davelawson2564 manufacturing of cement is an extremely dirty process and it uses very scarce raw materials, like sand.

[@davelawson2564]

@@Teporame LOL ! asphalt uses small stones. you can make sand by crushing the same stone. The fact that concrete roads last 100 - 150 years unlike asphalt useless roads that fall apart in 2- 10 years depending on road build quality. concrete roads are 10 times more coast efficient and saves tax funds and gives better quality roads

[@vanbeet5105]

@@davelawson2564 This is very true; actually i was surprised to hear him say that asphalt roads are more economical than rigid pavements (concrete roads) because its just straight up false. A rigid pavement may have a significantly higher initial cost, but its way more economical in the long run as it barely requires any maintenance (if properly designed) and has a way longer design life than even the best designed flexible pavement (asphalt road's design life of approximately 15-20 years is only possible with extensive and expensive repairs)

[@mikewalding8639]

I’ve been in the road building business for 40 years in Florida and just wanted to say this is the Simplest explanation of building roads I’ve ever seen. Great Job

[@MrBiky]

"I will always be there for you when you fall" - Asphalt.

[@garethbaus5471]

I remember that I once fell on asphalt walking to school because of black Ice there was a raised concrete curve that had its edge right where my neck was, I probably would have been seriously injured if I wasn't wearing a loaded backpack.

[@KruhlSentru]

@@garethbaus5471 I had a fall like that once, but instead of my neck, the curve hit right in to the back of my head. Somehow, I escaped with nothing more than a bruise.

[@DanielGomez-fk3on]

@@KruhlSentru oof. Glad to see you made it through alright

[@matthewbarksdale1300]

Gareth Baus “when you fall, I will be there to catch you.. time after time”

[@mpdavis731]

"Gee, thanks a LOT!" - Knees everywhere

[@WaffleAbuser]

Another advantage of asphalt: its color. When driving on a light gray concrete asphalt road while facing the sun, it can be really difficult to see the lane dividers. It's scary...

[@r3d0c]

disadvantage of asphalt's color, heat island effect in cities

[@WaffleAbuser]

@@r3d0c That's also very true

[@SGDrummer7]

On a lot of concrete roads here in FL they add black stripes near the white stripes to give contrast to the lane lines.

[@inisipisTV]

@@r3d0c - In Japan they invented a special grey additive for the top layer. It reduces heat by about half and makes the asphalt more resistant to water, since Japan experiences lots of typhoon.

[@dimesonhiseyes9134]

@@r3d0c in reality there is almost no difference between concrete and asphalt. The only real difference is between new asphalt and new concrete. But as they both age rate of reflection starts to converge.

[@snuffeldjuret]

nothing beats bicycling on a newly paved asphalt road :).

[@Peanutbutter_Funk]

Except skateboarding on one. 😍 I haven't skated for years and bike commute regularly now, and I still stand by that

[@drod3434]

Or driving with brand new tires.

[@banjopete]

Except everything else.

[@kaydog890]

Anything with a motor.

[@orppranator5230]

peter olsen gayy

[@kennethbailey2616]

Bituminous concrete is what my dad called asphalt in his technical papers. He once helped design an asphalt for a NASCAR race track (Watkins Glen).

[@nolesy34]

Very naaase 👍👍

[@jscancella]

My first job after college was as a construction inspector for roadways. The one thing I learned is that if you don't get the sub base correct, doesn't matter how good the asphalt is it will crack and be bumpy. I wish my local town would understand this, and stop just resurfacing the roads when there is clearly sub base issues (alligator cracking)

[@whuzzzup]

I wish they would hold the construction companies accountable to the shit they build.

[@dimesonhiseyes9134]

As an inspector as well I can also tell you that problem usually comes down to money. Complete road reconstruction costs a lot more to do.

[@JakubNarebski]

@@dimesonhiseyes9134 Though they probably cost less in the long time (reconstruction vs repair after repair).

[@bbcastillo1316]

nice job

[@dimesonhiseyes9134]

@@JakubNarebski that is often the case. But road construction is just as much art and magic as it is science. It's always a balancing act between the money you have now, the money you will have later, and time. There are often trade offs that have to be made. I have had jobs where we did a portion of the job as a complete reconstruction. And portions of the same job were just a mill and overlay. Those portions of complete reconstruction cost considerably more. And took multiple times longer to complete than a similar distance with just a mill and overlay.

[@lappinrappin]

I love how you concisely explained the differences between Roman road use and our use of roads today in relation to their perceived lifetime. I will remember that.

[@dimesonhiseyes9134]

Not to mention the Roman roads that "are in use today" have been rebuilt and maintained.

[@Yora21]

I've seen some original 2000 year old Roman roads. They are still very much recognizable as roads, but they are in really bad shape. You wouldn't want to use them with a bicycle, or even pushing a stroller on it.

[@dimesonhiseyes9134]

@@Yora21 right ok I'll grant you that. They are basically walking trails at this point. However the roman roads that people thj k of when they think of roman roads that are "still used" have been rebuilt multiple times. And are maintained quite extensively. I used to work with a gentleman that did it in Italy.

[@jfbeam]

St. Marys St. in Raleigh NC still has a 100+ year old cobblestone base. When it was resurfaced many years ago, you could see what it would be like to drive a modern car on a Roman (like) road. It's very loud, and very uneven. And as long as you keep 40t truck off of it, it could last 1000 years. But you absolutely don't want to use that for a modern road. It's drivable, if only barely, because the speed limit is 25mph. The faster you go, the less control you have as the tires are in contact with the surface less and less.

[@dimesonhiseyes9134]

@@jfbeam a closer example would maybe be a street made out of pavers. They are very common in Latin America and Europe. They are pretty durable but offer very poor ride quality. They use them in Latin America because they are cheaper to maintain. When the road sinks you just dig them up and re set them. After all people are cheap when they get paid just a couple dollars an hour. Materials are expensive.

[@Tdubs241083]

As an Electrical Engineer, I never thought anyone could get me excited hearing about Civil Engineering stuff. Glad to be proven wrong. I have been enjoying all of your videos. Thank you :)

[@janus3555]

Similar case here, but with a slight twist. I oddly enjoy civil engineering stuff as an avionics electrical engineer with a phase background (USAF), and while I love what I do, aside for the occasional 14 hour nights with my head in an 1800 page WD under a canned jet, if things were slightly different, I'd be a civil engineer. I went to school initially in the late 90s for Architecture but then 9-11 happened. Since then I've revisited my old interest and realized civil engineering was more of what I wanted but never knew it. Either way, Electrical or Civil Engineering, I'm at least glad I didn't go the architecture route.

[@BennyPowers]

Hi Grady I really appreciate your positive attitude and enthusiasm for your field. I wonder if you ever get discouraged or frustrated with civil engineering and would like to hear about how civil engineers deal with those experiences. Keep up the wonderful educational work

[@Leanzazzy]

As an actual civil engineer, I am amazed at the level of detail and how much information you have included in your video. You broke down a complex topic and still made it interesting enough for the general public to watch and understand.

[@bobdemeo1935]

Iiiiokoooookkkkkjkkjhhknjjj

[@endingtasks8538]

I'm looking forward to be one, what advice do you have to someone looking to major in that degree?

[@Leanzazzy]

@@endingtasks8538 I will give you some general tips for any career. 1) Make sure you like it and know what you are getting into. The best way is to ask a friend or someone you know in that field if they can allow you to accompany them to their workplace and watch them working for a day. Or during "Open days" at schools and universities you can talk to people in that field. 2) Check that there is actually demand and job opportunities for it wherever you live or intend to live. Too many people graduate and cannot find a job.

[@Leanzazzy]

@@endingtasks8538 What branch of Civil Engineering are you interested in? Remember that most of the time you will be starting as a site engineer. If you live in a hot or tropical country this is literally hell. Aside from sunburn and heatstroke, you can get dehydrated, skin cancer and on top of that sites in general are extremely dangerous because there are no railings or proper safety structures etc because everything is still under construction.

[@patience__8051]

This is teaching done right , I didn't even see that it was 11 minutes long , yet I learned things about roads, which I thought where boring as hell If only all teachers could teach like this

[@mina86]

‘If only all teachers could teach like this’ - you mean provide high level information only without any details which one would actually need to apply the knowledge?

[@alecnolastname4362]

mina86 So what exactly is the information that you still require? The volume of asphalt needed for 100m of roadway? The temperature it needs to be to be worked? How to properly grade a curve in a road? How to operate the machinery? The specific chemical additives and mix ratio used to make roadways more durable in the surrounding climate? What materials should be used for the subsurface? How thick the roadway should be? The topic itself was asphalt, not construction.

[@thaothelazycat930]

@@mina86 I think the author of this post meant that the way the content is presented is engaging and informative, something that he or she wishes that more teachers could do.

[@mina86]

@@alecnolastname4362, if all you care about is surface level details, stop comparing it to school. There’s no more information I require, but I’m not the one making a moronic analogy to teacher at school or university.

[@mina86]

@@thaothelazycat930, he specifically accused teachers of doing teaching wrong and to support that accusation he used comparison to type of teaching done in this video. This comparison is moronic (since compared to what you learn in school, you learn nothing from this video) and unoriginal.

[@mechailreydon3784]

I’ve really started noticing and appreciating well maintained roads. It’s so satisfying driving on a good road.

[@frankjrmuchnok2647]

When I was around 12YO and a dedicated skateboarder, the city paved a side street, a good downhill slope with several beautiful curves. I spent that summer doing my best to wear a groove into it. A very fond memory of my youth. Love new blacktop !!! Also, "Chip-Seal", otherwise known as "Two-Minute Auto-Paint Remover".

[@nunyabidness117]

I was in the middle of nowhere on the back roads of Kansas when I saw a mobile resurfacing setup. They ground up the old road, mixed it with fresh asphalt oil, and laid it right back down again.

[@joeyknight8272]

Wow

[@mahadlodhi]

That must have been a treat to watch

[@crusherven]

I've seen something like that before. It was really cool.

[@dogwalker666]

Tarmac

[@nunyabidness117]

@@crusherven I thought so too. It was one of those elegant engineering wins that solved multiple problems simultaneously.

[@suryahr307]

I just completed 2 years of masters degree in pavement engineering. I wish I was introduced to the course like this at the first day of college. Awesome video! Every point he tells casually has lots of research behind it 👌

[@charlieangkor8649]

I think schools and universities are crap at teaching.

[@SweatyPotatoChip]

Yes for the most part, it was correct. There's some things here and there that were incorrect, but that may be due to where I'm located. Overall, it was a pretty good job.

[@dogwalker666]

Quite a few errors actually. I was visiting the saint gobain testing labs who own "Tarmac" the company , showed me the pages of mixes for tarmac, weather it's for roads, pavements, carparks, low noise, high or low temperature, they even adjust the coefficient of grip, there is a lot of science in mixing.

[@SweatyPotatoChip]

@@dogwalker666 that's pretty interesting. Me living in a state that does testing differently from other states, you don't have the luxury of learning that stuff like high/low temp, dampening the road noise stuff like that

[@dogwalker666]

@@SweatyPotatoChip One of the reasons the city roads are failing so quickly here is because they were asked to supply a low noise version which they did however the low noise mix failed premituly now the council's have hundreds of miles of new roads that need repair plus the older ones that were scheduled for replacement, they just can't cope.

[@SelfTappersnWranglers]

Dude its so crazy like getting to know about these things. You would never really think about how a road is made. Yet it’s something you use everyday. Love learning these types of things

[@SteveCentra]

So insightful. Your videos make me appreciate the thought put into making our world. Thank you!

[@TheImmortuary]

Asphalt gets such a bad reputation in the areas of the world that see more free/thaw cycles, but really there is no better, more versatile, more recyclable, and durable material for road building, hands down.

[@Alighierian]

Part of that is down to maintenance. If you expect a thing to do 10X, but you only maintain it up to 5X, shit breaks.

[@justarandomweeb3220]

Here in philippines asphalt is so bad. I dont know if its because of underbudgeting or the weather here is just that terrible.

[@justarandomweeb3220]

But the only thing for sure is politician destroy the road and "fix" it just to make name for the public

[@TheImmortuary]

@@justarandomweeb3220 sadly many municipalities exploit this fact. As explained in this video, the quality of the bitumen and the rock, as well as other additives, can extend the life of roads for many years. HOWEVER, to the untrained eye and those not IN THE KNOW, you cannot tell a high quality paved surface from a poor one when its fresh, but after some time it becomes apparent, but then the same company that laid it down is contracted to maintain it. Not everyone tests, I learned that from experience. Its a constant 'make work' project, that lines the pockets of unscrupulous officials.

[@wildmonster1]

The Great Pyramid Erection yup and it’s worse when it 3 months later in Minnesota that it becomes literally 95 degrees f

[@thegoldenone445d7]

The world's most recycled material Air: are you challenging me?

[@David-pm9fi]

Water: You fancy the title?!

[@cboechler7]

@@David-pm9fi earth. Fire. Long ago, the four nations lived together in harmony. Then, everything changed when the Fire Nation attacked. Only the Avatar, master of all four elements, could stop them, but when the world needed him most, he vanished. A hundred years passed and my brother and I discovered the new Avatar, an airbender named Aang. And although his airbending skills are great, he has a lot to learn before he's ready to save anyone. But I believe Aang can save the world.

[@jacoboopy9150]

Is air a material tho?

[@SuperPhunThyme9]

Don't you mean come at me bro?

[@thegoldenone445d7]

@@SuperPhunThyme9 no

[@gobbletegook]

After watching the reconstruction of I-94 between the ILLINOIS state line and MILWAUKEE, the amount of concrete reclamation was phenomenal! There were 5 - 10 story tall mountains of the broken up stuff, most of which we were told was re-used in the rebuilding and expansion of it.

[@brodewall5641]

As someone who works in the industry it’s so fun to watch someone get excited about paving as I do. It’d be cool if you went further into why asphalt concrete fails specifically and what types of failure are common. And a bit more about mix design would be super interesting.

[@ras573]

So, why and how does it fail? Is it possible to engineer some kind of super-asphalt, that doesn't lose quality so fast?

[@davidha44]

@@ras573 I work for my province's transportation authority and I spend a great deal of time dealing with highways as you might expect. There are a lot of reasons for failure, though the most common in my area is temperature fluctuation. As mentioned in the video, asphaltic pavements are designed to flex, but when they get too hot, they can flex too much (which can result in wheel ruts over time), or too cold, which can result in cracking due to being unable to flex. Most asphalt mix designs attempt to account for this by providing a specially designed PGAC (Performance Graded Asphalt Cement - the binder that holds the rocks together) that meets the temperature requirements of the area. The PGAC is designed for a maximum and minimum temperature in which it will perform properly. In my area, a 64-28 PGAC is common, meaning it can withstand temperatures of up to 64 Celsius and down to -28 Celsius. In areas where the temperature fluctuates less, they may use a different PGAC. In the vein of temperature, another common cause for failure in pavements is due to movement of the subgrade (the rocks and soil underneath the pavement). One common issue is known as "frost heaving", which is the subgrade literally heaving upward due to ice forming in the soils. This can be mitigated by building your subgrade out of materials that are less susceptible to frost. Rebuilding the subgrade is a time consuming and expensive process as you might imagine, since you are not only removing asphalt, but the material underneath it and replacing all of it. This can be part of the reason construction seems to take so long, since they're rebuilding what is essentially the foundation of the road. In a case where the contractor is only removing asphalt and repaving, it takes very little time, generally speaking. Other potential causes of failure often are results of the construction process or the materials used. In my work, we have very stringent standards and specifications that contractors MUST adhere to, that help us get the best product. It's also why contractors charge more to do government work than for say, paving your local grocery store parking lot- because we hold them to a higher standard in order to get a much better product. Main factors that affect the quality and durability of pavements include compaction, percent of asphalt cement (AC) in the mix, properties of the aggregates (rocks and sand) used, segregation in the finished product, and a few other things. Let's start with compaction - we specify a minimum and a maximum percent compaction for the asphalt. You've undoubtedly seen those massive steel drum rollers they use... the drums vibrate and help knit the mix together into a tight, well compacted surface. Compaction is checked in the field by use of a nuclear density gauge, which is placed on the surface of the asphalt and measures the compaction approximately (I won't get into how it does it, but basically it bounces radiation off the asphalt and performs a calculation). It is further checked (much more accurately) by taking cores out of the asphalt. Generally, a set of 3, six inch diameter cores are cut into the surface, removed, and tested in a lab with a series of tests that accurately read how well the asphalt is compacted. Poor compaction can result in moisture getting into the road surface and causing cracks over time. It can also result in rutting, as there are too many voids in between the aggregates, allowing the surface to bow and rut. The reason we set a maximum limit for compaction is mostly because over compacting the asphalt can cause it to crack prematurely from the stress. Basically you're beating it up and it starts to separate and break. Percentage of AC in the mix is important, as the AC is basically the glue that holds it together. Not enough glue, it can cause the asphalt to crack and come apart, allow moisture in, and degrade. Too much glue, and it starts to bleed out the top of the fresh asphalt, which can cause poor traction (since it's so smooth). Properties of the aggregates - This is extremely important, just like compaction. The asphalt mix is designed to have very specific proportions of different sized aggregates in it, from mid sized gravel to extremely fine sand. The mix is designed and tested based on these proportions, and if it passes the litany of laboratory tests, it can be used. The contractor (or their asphalt supplier if they don't supply it themselves), will design a mix that meets the specifications of the project they're working on, and attempt to produce asphalt with the properties laid out in their mix design report. As the asphalt is laid down, occasional samples are taken by a trained quality control (QC) worker. Generally, the QC worker will gather fresh asphalt from the paver as it moves along the road placing asphalt and put the aphalt in a container (often a box). Generally, 3 boxes are filled per sample - 1 for the contractor to test, one for the owner (the person paying for the work) to test, and a third used as a "referee", if the contractor and the owner results disagree. The referee sample is used basically as a tie breaker. If it agrees with the contractor result, then their results are used. If it agrees with the owner, their results are used. Referee samples are not used if the owner and the contractor get the same results from testing their samples. Anyway, back to the sampling process. Once taken, they go back to the lab for testing. These tests check that the sample meet the requirements laid out in the mix design report. If they don't the pavement may need to be removed, or the contractor may have to accept less money for the work. Lastly, is segregation, which is a very common problem and one of the easiest ones to spot. It occurs when the fine particles (the sands) and the coarse particles (the gravel and rocks), get separated while being placed. This can occur due to over compaction, poorly mixed asphalt, or placement methods that are less reliable, like using shovels and rakes instead of a large driven paver. When the aggregates are separated, the surface of the pavement looks very "open", sort of pockmarked and with large gaps in it. This allows moisture in, it can allow larger aggregates to "pop out", wherein they are knocked free of the surface by traffic or temperature flexing in the surface. Segregation is usually dealt with by removing the affected area and repaving, unless it's relatively minor, in which case the contractor may just be issued a reduction in payment. I hope this large wall of text isn't too confusing. If you have any questions about my points, I'm happy to explain myself. Cheers :)

[@ras573]

@@davidha44 Thanks for such a detailed answer. I was wondering what book to read this week. I'm joking... What do you see potentially replacing asphalt in the future, if anything? How will roads advance? And I don't mean incrementally, but, what can be done to radically increase the quality, or decrease the cost of asphalt, and roads in general?

[@bdjonter6122]

Congrats on the baby Grady!!

[@JeroenvanMontfort]

Congrats Grady!

[@Nighthawkinlight]

I'd like to see a video from you on various recycling methods, possible solutions to the lack of domestic recycling (or ways it exists that you may not expect) etc... I've wanted to make a video on the subject ever since learning that shipping labels are non recyclable, which is pretty outrageous considering they're impossible to peel off in one piece. I'm not qualified to know what I'm talking about concerning industry practice so it would be nice to hear from someone who is. I've taken to burning all my cardboard to heat my barn as that seems more useful than rotting away in a dump.

[@MrNeilSherman]

second - Scruffy, janitor.

[@crispy9566]

Having been taught to sort trash at home for all my life, it seemed like a no-brainer to me but I was shocked when I first realised how complicated it is to develop an effective domestic recycling system/infrastructure and that how many places around the world don't sort trash at home, because their municipal waste collection/treatment just dumps/burns everything or ships it to africa/asia. And I agree that seeing videos abouy recycling in general would be awesome!

[@larryteslaspacexboringlawr739]

yes since you can build out of materials that absorb carbon and other green house gases, like hempcrete

[@jigurd]

Always fun to spot another youtuber I follow in the wild. Been following your stuff since 2011! :)

[@Poprotta]

Im so baffled about the american way of not getting money from recycling your bottles. In finland you pay the 15 cents when buying the bottle and get that money back once you recycle the bottle.

[@joemehere1151]

I always enjoy the Practical Engineering videos. I started watching from the "Champlain Tower" disaster. They were so far ahead of everyone else as far as plausible/probable cause and always right! Thanks

[@jliller]

I remember when I first moved to South Florida in the paved two-lane rural county road passing in front of my home had a lot of shell included in the aggregate. Not so when it got repaved a few years later.

[@ghostindamachine]

In The Netherlands a form of asphalt concrete is used called ZOAB, which stand for Very Open Asphalt Concrete. Its very porous, so it drains rainwater very excellent, reducing water spray on highways to an absolute minimum.

[@LeoLeo-qo7yw]

As far as i know, water leaking below concrete isn't good.

[@dennisphoenix1]

@@LeoLeo-qo7yw what he means is the top layer of asphalt is permeable, under that layer is an impermeable layer . Instead of water travelling across the surface to the drain it travels under the surface so no risk of aquaplaning on standing water . Doesn't work where you get frosty weather.

[@greg5297]

A lot of studies have gone into "permeable asphalt" like you mentioned. The thing is that usually the surface starts off permitting groundwater, but as time increases those pores fill up with dirt, grim, oil, etc and the roadway no longer allows water to filter and drain like it used to, turning it into a normal road with normal drainage properties. We use them a decent amount in California because they are more "environmentally friendly" but most people in the industry know they are just a way to prolong the inevitable.

[@traumiweber6600]

It has a really nice sideeffect, it breaks the noise in those gaps which makes it really quiet. That is the main reason we use it in Germany on the Autobahn in the cities, even tho it is not so durable like regular asphalt and needs to be replaced sooner.

[@chencheng7695]

It's funny I just got back from a job today where the crew were laying down the porous asphalt you are talking about. It's called OGFC here and it stands for open graded friction course. It let water go through the top and drain out from the second lift which connects to Catch basin. Driving on this type of asphalt generally produce less noise which is needed for this section due to animals around the highway that are sensitive to sound.

[@reecepempeit3896]

congrats on being a soon farther, hope you raise the best lil engineer ever

[@pelegst]

His wife is not pregnant -- she is engineering the baby.

[@mfaizsyahmi]

lol brady is set to become like that character in 3 idiots, ViruS: "if the baby's a boy: engineer; if a girl: doctor."

[@hsvr]

You stalker

[@FruitzApple]

Meaaannnn I kinda think he should raise a kid... It would be kinda weird to raise a lil adult that has already gone to school for engineering and not the kid that comes out of his wife just saying :/

[@Videillosywea]

Sorry no engrish

[@kizunadragon9]

Just had my driveway done. went from a compacted loose stone driveway to a nice giant U shaped path of asphalt. Love it.

[@encellon]

Chip seal was used on a fairly busy road in our town in the mid-1960s and lasted without any cracking or potholes for more than 40 years. It's a mess when it goes down, but given a solid base, it seems to last a long time.

[@TheKnaeckebrot]

I can almost smell this video :D

[@binkalink420]

That's the smell of black gold

[@JaidenJimenez86]

Why is it such an appealing smell?

[@binkalink420]

@@JaidenJimenez86 same reason gas smells "so good" it's refined petroleum.

[@jg77516]

I used to work at a road recycling and grinding company it was pretty cool to see. On the front end you have a tanker full of A/C tar mix, behind that is a Wirtgen 1050 Grinder that pulverizes the existing road to depths up to 300mm, a hammer mill that completely grinds up all the old material and also mixes with the tar I mentioned earlier, and that shoots into a hopper on the paver at the very back. This is all followed by a few double steel rollers and rubber tire rollers for compaction and smoothing. It’s quite a delicate process as you have to make sure everything is being mixed to the right percentage of aggregate:tar, road width, road crown and grade, and compaction. I even got to take samples and send them to AME so the engineers can assess old roads for new projects, and newly paved ones we just did to check compaction, moisture, and mixture.

[@tywilkins2584]

That’s what I do for a living now. I run a Wirtgen 250i Milling Machine and tear up the Asphalt, and shoot it from the conveyor to the back of the dump truck. (Like shown briefly in the video) Very cool process to watch. A lot of HOT hard days of work. But it’s a recession proof business!! Haven’t missed a day of work since Corona outbreak!

[@brandonarnold9673]

@@tywilkins2584 What's the 250 like? The company I work for recently got a set (210 and 220)

[@jg77516]

Ty Wilkins - Oh yeah man 🤣 16 hours or more most times it sucked

[@hydragons]

@@tywilkins2584 even in stage 4 Melbourne strict lockdown Road work is still going strong.

[@tywilkins2584]

@@brandonarnold9673 250 is nice. Hydralic teeth removers, dual engines (for less bogdown on deep cuts), and our company bought the larger drum as well. (mostly for interstate jobs) Our crew is supposed to get the 210 HI soon. And from what im hearing its quite the improvement. Much easier to change oil and fuel filters. And alot easier for the ground man as well.

[@gustavouchida1]

Nice and thorough explanation. Missus looked nice as well. Congratulations for the new family member!

[@ilovetotri23]

My head is spinning! I am an engineering nerd with very little engineering schooling. I have always wondered why they use different materials to resurface the same road or different roads in different areas. I do understand the physics of the qualities of materials strengths and weaknesses. Overall, I love the fact you are describing things I wonder about daily, but have zero resources to actually help me understand. Thanks for the great video!

[@JeffMTX]

Uh, internet

[@KishorJoshiMCh]

Grady is the first person to smile with joy while saying "Asphalt" and "bitumen" :-) Nice video.

[@mro4ts457]

*Salesman* *Slaps asphalt “This baby can be recycled so much”

[@Alex.AL_26]

the roads were being re-done in my area in they recycled the materiel right on the spot, the company was called Hot in place recycling and they used equipment to heat up the asphalt they add the tar binding materiel and they spread it out again. it was really cool to see in person.

[@Transit_Biker]

They started doing that with busy highway ramps here. The resultant texture is actually helpful in rain/snow.

[@quinntitchkosky5396]

It's super neat to watch but it smells so bad. I'm surprised they don't have to wear respirators when working with it.

[@Alex.AL_26]

@@quinntitchkosky5396 i actually like the smell of the blacktop

[@williamkirk7781]

I love that smell, can't wait for layoff every season

[@tclott316]

Yes sir. I work for Hot in Place. We travel literally all over the country, coast to coast. We’re based in Thornton, Illinois. We add the rejuvenating oil because we get the existing asphalt so hot, we bake the oil out of it. As far as masks, our company does extensive tests on the oil we use to make sure we are 100% safe. As far as the smell, you get used to it. And the heat, it’s really not that bad lol, you get used to that really quick also.

[@pqrstzxerty1296]

3:50 Not in England 2019 - 2021, Roads here have so many potholes, subsidance and tears, due to years of cheap repairs using what I call hot bitumen paint spraying on the top, and a truck sprinkling some gravel.

[@4192362]

top dressing

[@IBENGM]

Thank you for making these videos, i learn and enjoy them alot..please keep doing what you are doing!

[@theultimatereductionist7592]

9:10 Duck engineer: Ok, we've built this road's tolerances to withstand the heavy traffic of a family of ducks crossing over it: I think we're good.

[@ErilynOfAnachronos]

Oh definitely, it can even hold a zebra.

[@dembro27]

"Duck engineer" sounds like quackery to me. Still, it's nice to see the ducks can cross it safely.

[@explosivemallard8038]

If anyone ever sees a career or job opening for "duck engineer," I don't care if you see this 30 years late, I could not be physically or mentally more willing to take that position within the next hour. I'd move anywhere in the world for that. This is the ultimate dream, and I've been training for it since my conception.

[@janus3555]

Very important consideration seeing as it requires a lot of math and studious learning to 'keep your ducks in a row'.

[@michaelbrace6580]

I work as a chef and started taking an intro physics course to catch up on all the stuff I didn't care about in high school because of you. Engineering is super interesting and if your videos were around when I was younger I would have chosen a different career. Thanks.

[@mrzeppelin4life]

It's never too late Michael :)

[@michaelbrace6580]

@Big Foot ok?

[@jimrossi7708]

As a small child back in the early 1960’s my friends and me would take our Tonka trucks and build roads in my backyard near the park and out of the way of our parents, if I could have gotten the training I would have loved to be a big equipment operator but settled on being a tractor trailer driver for 40+ years and seeing so much of the USA and Canada, I always loved learning about what went into building infrastructure and find it so interesting, so thanks for so many of your videos dealing with that and so much more !

[@natalieardner5509]

I live in Columbus, OH. ODOT has about a 10 mile stretch of US-23 north of Columbus of different types of test pavements! It's really cool and has been like that since before I was born! You can hear and feel the differences in the blends of concrete that they use!

[@MaxPower-11]

I remember many years ago I saw a bumper sticker on the back of a paving company’s truck and I thought it was cute. It said: “If you used concrete in your driveway and it cracked - it ain’t my asphalt!”

[@united3689]

brilliant hahah

[@ericmendez5815]

Don’t ever say “Cute” again unless you’re a Wussy or you’re being sarcastic!

[@whatshappenedhere1784]

@@ericmendez5815 Someone is scared of their own masculinity

[@firethylacine1976]

@@ericmendez5815 Cute! Are you scared?

[@cursedcliff7562]

@@ericmendez5815 oh man that kitten is so coot

[@JRScience]

When I was a kid, my dads friend would pull over on the side of the road an pickup the "scrap" pieces of asphalt and would add them to a pile at the top of his gravel driveway. Eventually he had enough and paved his own drive for the cost of the machine. I'm sure picking up asphalt scrap is theft to some degree, but he did it.

[@solstice2318]

Sounds like a fan of Johnny cash 😂

[@muhughu]

@@solstice2318 "I got it one piece at a time, and it didn't cost me a dime"

[@TheLoksta123]

Honestly no one would ever notice asphalt scraps go missing, we only deal with tons when measuring how much asphalt we need for a job and how much is being recycled. So unless he was taking more than 100kgs at a time then no one would know or care hahah

[@JRScience]

Muhughu - lol thanks. I was trying to find a Johnny cash asphalt reference. It makes sense now.

[@MrDoboz]

yeah the wear on the brakes, the gas for getting back to speed, and his time probably costs more than the occasional handful of asphalt he got. He was probably pretty stupid. Either that, or he stole tens of kgs of asphalt per stop, and that's not too legal.

[@jbgaud]

this is, by far, the best adventising for modern technology I have ever seen. Thanks for that.

[@chance1986]

Not sure how (or why) I found this channel. But I'm really enjoying and learning from Grady's excellent presentation and video production.

[@Elastane]

Solar Roadways "we're so eco!" Asphalt "hold my beertumen"

[@FreeRangeLemon]

Looked it up, solar roadways look cool. Obviously would be extremely expensive though.

[@dimesonhiseyes9134]

@@FreeRangeLemon they are also a complete failure. In every way.

[@nilsgeurts]

HalfUtilitarianist in the netherlands imtech experimented with it, too expensive (project : solar road)

[@dimesonhiseyes9134]

@@HalfUtilitarianist probably the best example of why not to trust social media marketing and initiatives

[@dimesonhiseyes9134]

@@nilsgeurts not just too expensive also complete failure in every way.

[@TheClamy8911]

This hits home because I’m a laborer on a paving crew.

[@mr.ducarbre9065]

Must be suffocating when you work during summer daytime. I hope the foreman's treating you guys well.

[@TheClamy8911]

Mr. DucArbre yeah man it is, that stuff is so hot to begin with. Glad someone feels for me haha. Yeah man he’s a great guy he busts down and works with us! Best wishes :)

[@CoconutCrabGaming]

Same here brother, 6 years on a crew and still going strong!

[@steyn1775]

@@TheClamy8911 maybe wear an utilitykilt at work?

[@Transit_Biker]

Stay safe! ✊😷

[@andrewbrenner425]

Your videos are awesome. Great mix of technical information and presentation in a way the average person can understand. Well done.

[@Robbythegod]

In Devon, UK we now use 'Warm Mix' asphalt ~140°C. This takes less energy, lower carbon cost of construction

[@billschlafly4107]

I'm a civil engineer and I very much appreciate this channel for explaining the important aspects of what is otherwise considered to be mundane for non-engineers. Thanks for the validation and congratulations to you and your wife on the new addition.

[@MTWODZU]

0:00 - If you ride a road bike, you always notice roads and especially surface quality :)

[@charlescourtwright2229]

its why my new bike has 2.5in(~6cm) tires, it can handle even my shitty ass roads

[@beyerdr]

In Alaska we have seasonal weight limits. Between of the extreme cold see here in the interior, and then the saturation of the soil that can occur during breakup season as all the snow melts, our roads have a pretty tough time in the winter into spring. So they sometime in late may they announce the "weight restrictions have been lifted" and you can start hauling dirt and gravel to do the driveway work that ends up needing done after a few winters of abuse.

[@emmaacquah6798]

I really enjoy your videos but this in particular is my favourite because for my master thesis, I did some research on nanomaterial particles as modifiers in asphalt mixtures/concrete. Keep up the good work sir🙏

[@gregking267]

I had always wondered why all roads aren't made of concrete. Great overview!

[@MikeV8652]

@Bruce Wayne Wow! I grew up in Louisiana: Buh bump, buh bump, buh bump, buh bump, buh bump...

[@Maazin5]

Congrats on (soon) becoming a dad!

[@Realkeepa-et9vo]

I'm kinda terrified of the dad jokes that come with this

[@long6live6metal6]

More on that later

[@devanshdoshi5385]

@@long6live6metal6 😂😂

[@omniyambot9876]

wait, he had sex?

[@jackhammond2230]

this will be weird when the kid is like 8 years old

[@zyxlsy]

Being an Engineer myself, I just love how realistically practical the contents of this channel are. This is what engineering should be - with little ideologies as possible. We care about lowering energy consumption, in fact, that's a huge part of what we do. Though, I'd always ridicule ideas like we can generate electricity with love...

[@infamoussoul2346]

We can't generate electricity with love 😢

[@Xirrious]

You can generate plenty of friction with love though.

[@calorion]

Some decades ago, I saw a news segment about a revolutionary new asphalt-replenishing vehicle that would dig up existing roadway, remix it, and lay it back down over some sort of fabric substrate, all in one go. I wonder what happened to that?

[@SpeakerMunkey]

Congratulations on the upcoming third member of the family Grady!

[@Billy-jf6rb]

The hardest part of laying asphalt is remembering “black side up”.

[@quincekreb6798]

🤣🤣🤣

[@SuperPhunThyme9]

Woops

[@ErilynOfAnachronos]

Reminds me of my 10 year old classmate during PE, the teacher said "now lie down on your back", followed by "Menno, other back."🤣

[@SC-RGX7]

Always forget this one🤦

[@omega7311]

Same with turf

[@sirapple2406]

What we do in the Netherlands is give the asphalt a wear layer, this makes sure that we only need to regularly replace the least amount of material possible.

[@Lucifer_26]

Also many of our roads have added stuff that makes them somewhat spongy, which makes them more expensive but improves road safety a lot when it's raining heavily preventing aquaplaning.

[@trulyinfamous]

@@Lucifer_26 and porous asphalt reduces road noise by a significant amount. I bet that even the things that the Netherlands does poorly is still done better than in the USA.

[@sirapple2406]

@@trulyinfamous Mostly because we have the luxury of politicians who still have common sense and are generally trying to *improve* the country.

[@jasonrevelation1582]

All new pavement has 15-20% recycled asphalt in it, so we do make more than we recycle, but we can keep recycling in perpetuity. 100% recycled in place is possible but that is specialty equipment and specialty companies (see $$) usually reserved remote stretches of highway. Cool fact on asphalt thickness/cost relationship: The pavement layers must be 3 times as thick as the grade of rock making up the mix, most commonly 1/2" or 3/4" rock. So if you are doing a road in 1/2" mix, your mat thickness should be no less than 1.5 inches and no less than 2 1/4 inches for 3/4" mix. Contractors like to save money or bid more competitively by putting down thinner layers so you're totally right about how adding even a 1/4" inch in thickness can add tens of thousands more $$ to a bid.

[@thevr3dprintingguy253]

So I work for the Nevada Department Of Transportation as a highway maintenance worker and you really hit the nail on the head here. I have done chip seals, pothole repair, and many other things. Out here we don’t have to worry of the roads getting to cold but we definitely worry about them getting to hot. Hot roads can lead to raveling and bleeding. Really love the videos you put out. Keep up the good work.

[@virgilmanson214]

I love how well he teaches. Very professional and kind.

[@saucedog6725]

As someone who’s been paving asphalt in a dump truck for over 2 years now this video was really interesting to watch !

[@nolesy34]

Wait.. why pave from a dump truck and not the regular paving bitumen supply truck

[@louf7178]

In recent concrete driveway practice, saw-cut joints have been the norm. I believe they all crack much more quickly than radiused edging due to stress concentration (especially at 4-way corners) - demand radiused edging.

[@ctcamara]

I work on the paving field for about 10 years and I thought your video is amazing! Thanks so much! I'll definitely use it to train new employees! Congratulations!

[@juliantrueman6542]

I love how he made thos whole video because he saw the "roman engineers vs modern engineers" meme abd got angry about it

[@zacjohnson452]

How you know?

[@zacjohnson452]

Sythentic_republic ok, thanks

[@farhanmufid7919]

Because when romans build the road, there's no truck passing and anything that heavier than a horse :((

[@therosijedha]

"any trip made by car, bike, or public transport need roads" Planes, Trains, and boats: are you challenging me?

[@Aryescent]

i respect the people who make roads because it seems like such a slow process, especially for making extremely long roads.

[@TheRealUnconnected]

As someone that lives in a very hot, hilly city (Sydney Australia) it's been super interesting to see roads advance. When I was a kid almost all roads on steep hills were concrete because regular tarmac would melt in summer which you don't want on a steep hill. These days we've got roads that don't melt even when it's 30-45c in summer and the concrete roads are being replaced.

[@windhelmguard5295]

in germany, when it gets that hot, they cover the roads in really fine, but sharp grave. while the asphalt is hot and soft, cars driving over that road will press the gravel into the asphalt and afterwards the layer of brighter gravel can keep the asphalt below cool. after a few weeks of this a machine comes over to pick up however much gravel is still loose, to be used somewhere else. this leaves a coarse surface on the road, which is great in winter.

[@NedAndre]

Second Delorian I've seen today. Fix: It's "DeLorean". I'll get it right one day.

[@NedAndre]

@@MrSvenovitch Right you are. Spelling isn't my strongest suit! XD

[@WUZLE]

The roads leading through Agana, the capital city of Guam, had tire ruts when I was there in the 90s. I was told it was because it's always warm on Guam and the asphalt was always soft as a result. I was also a tar kettle guy for a couple of summers in Alaska so seeing unrepaired cracks in roads annoys me.

[@vorservla]

Really cool and eye opening video in some ways. Thank you for making it! 👍

[@Mrcaffinebean]

This answers a number of questions I’ve always had about roads.

[@pqrstzxerty1296]

My question is - how long is a road ?

[@eljijo23XD]

Congratulations on becoming a father! It is also very interesting to discover how the things we pass by every day without even think about are made, really makes us realize how complex the world we live in is and how much effort it goes into making sure it works properly

[@mazevx2451]

Your dedication to infrastructural engineering is very obvious on this one, it's refreshing!

[@spankeyham]

4.05 - I have seen and now driven on some permeable roads. Without a doubt they are amasing to drive on without the the risk of aquaplaning, 11/10 would recommend.

[@Lux158]

it is marvelous how you make something "simple" like pavement that interesting! good work!

[@civilengineerrajkumar7428]

Nice

[@echooscar5241]

Ask an Indian road contractor and he could make it even simpler. Unfortunately those roads don't last a year.

[@civilengineerrajkumar7428]

@@echooscar5241 ohhh you know Indian Road Contractor make it Simpler Thnxxxx Echo Oscar you know much about Indians

[@sfmc3000]

Cement must be heated to 1000 degrees centigrade and more ! Usually using coal in n order to manufacture the cement And f course using bitumen which is a leftover from oil refining and is another toxic substance we put in our roads and then the rain washes it into the soils and groundwater- just like Plastics is leftover gunk from the oil industry and this ends up in our waterways and oceans we make all of these so that cars which use even more CO2 in their manufacture and pump more CO2 when we run them. -- We should have stuck with the electric cars in the towns and suburbs and great train service to go from city to City as we used to do. . We had electric cars at the beginning of the century and there were over 15 thousand electric car charging stations in New York City over 100 years ago can you believe that?

[@civilengineerrajkumar7428]

@@sfmc3000 great knowledge R You Civil Engineer

[@Veeno00]

My immature brain was not ready for that pronunciation of "bitumen".

[@MikeV8652]

Yeah, I always thought it was "bi-TU-men." Of course, it really just tar.

[@JohnDowpe]

My immature brain : ass- phalt

[@inisipisTV]

@@MikeV8652 - Close but not exactly like tar, though have been used in ancient times to make Asphalt roads. Bitumen is made of different material.

[@reillywalker195]

It sounded just fine to my Canadian ears.

[@reaganharder1480]

@@reillywalker195 I mean, if you're in southern Alberta, your house is probably built on the stuff, no? There's certainly a lot of it around, anyway.

[@BotherNone]

I love your video's. I'm no engineer, but live learning about how our made world works. Also that was the most hearth felt sponsor spot ever.

[@doublexxgamer6612]

In germany we have something like a mix of asphalt and concrete called :"halbstarre Decke" or "Densitaspahlt" which means poorly translatet half-flexible asphalt toplayer.

[@theawsomedude37]

It's shocking how much we actually depend on Oil for applications apart from energy 😮. Almost all roads in the world....., how do we replace Asphalt in a post-oil world?

[@PanzerDave]

We will always use oil, at least for the rest of our lifetimes, and likely quite a number of generations. As you point out, it is used for many things besides fuel. Lubrication, manufacturing, and various other uses will require it's harvesting for quite some time. If we ever do get away from oil as a fuel, it will still be drilled, just in smaller quantities.

[@raystinger6261]

Well, because it can be recycled, asphalt would go on for quite some time even if we stopped all oil drilling, but it would eventually run out and then we would go back to concrete, maybe with stone bricks to save on concrete (I guess).

[@AsbestosMuffins]

ya but at the same time transportation and energy accounts for like 90% of oil consumption. in the US, roads constitute 350,000 barrels per day while fuel constitutes 9.5 million barrels a day, and you get much more fuel per barrel than you do asphalt

[@PanzerDave]

@@raystinger6261 There is a real possibility that we may never run out of oil. As PsychoLucario points out below, IF we reduce our dependence of oil for fuel, the oil will last a very, very long time and we are constantly finding new sources of oil. On top of this, we are also experimenting with other sources of oil, such as oil from algae. Just recently, the USAF flew a four engine jet entirely with bio fuel. This is but one way we may find new sources. There is also a minority held theory that oil is not abiotic, but rather a biotic process, and thus will always give us oil. While this is indeed NOT a mainstream theory, we don't actually know how oil is formed. The prevailing view is that it comes from dead dinosaurs and other decayed life, however scientists don't know the actual process, and are unable to replicate the process. There is always the possibility that we are wrong. The end result is that the idea that we will run out of oil someday is not a foregone conclusion. We might, but we might not.

[@okuno54]

@@PanzerDave IIRC, most oil is probably formed from dead trees from the Carboniferous, and the fact we can't replicate the suspected processes in a lab is that it requires extreme pressure, heat, and _time_.

[@JarrodBaniqued]

I’d be eager to see a collection of videos on railroad infrastructure-how much consideration goes into building switches, train control systems, signaling systems, electric power lines, railroad ties and ballast...they’re all so fascinating

[@ninja1676]

It's great to watch videos of different educational topics or subjects to gain more insights to what we use/have in our everyday lives.

[@hl6816]

8:37 All of the steam rollers moving back and forth made me laugh so hard!

[@LJCyrus1]

I find it odd that part of me still wants to call them steam rollers even though they're no longer powered by steam.

[@amyshaw893]

"but what do we do when the road starts to break down?" If you're in the UK, bugger all

[@-_James_-]

That's not true. Usually someone spray paints a cock around the hole and plants flowers in it.

[@AttilaAsztalos]

I thought that was the standard method. This whole "repairing" concept is just so alien...

[@rick9870]

the U.S. and Great Britain are "two countries separated by a common language" -- what does "bugger" mean? I watch enough British TV shows to know what "bollocks" means, but I havn't figured out "bugger" yet.

[@amyshaw893]

@@rick9870 I believe bugger is a slang term for... Entering the back door, if you get my drift. But used in the context of "bugger all", it means nothing

[@ALovelyBunchOfDragonballz]

They call a guy to measure the pot hole at the edges, and then he becomes a meme.

[@gabrielgade1112]

That kid is going to have the coolest school projects

[@capnstewy55]

You could do a video on when they tried putting asbestos into asphalt mixes.

[@Xlaxsauce]

We need a replacement for asphalt where I live as we got from -50C to +38C. It is amazing that we haven't changed as some roads are basically replaced every 2 years.

[@economicsinaction]

I never thought I'd sit through a 11mins video about asphalt, but this was really interesting

[@TheHammemo]

Here in New Zealand most roads are chip seal. Most of the time the "chips" get worn away completely or just flicked off the road and you're just driving on tar.

[@harveylong5878]

come here to the states where they seal coat the roads. pretty much 'painting' the asphalt. who needs black ice when the seal coat is greasy, it gets wet its an adventure driving on

[@focus123b9]

I love the finish part .. Smooth and shining