How Does Permeable Pavement Work?

Some pavement can let water in and keep everything else out.
Cities represent a remarkable transformation of the landscape from natural to human-made. One of the most significant changes to the landscape that comes with urbanization is impervious cover. That's anything that prevents rain from soaking into the subsurface: buildings, sidewalks, driveways, and the biggest culprits - streets and parking lots. Impervious cover is a big issue. When you pave paradise to put up a parking lot, you cause a pretty significant disruption to some really important natural processes in a watershed. But, not all cover has to be impervious.
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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]

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[@sonuyadav1182]

By solving one problem you're creating another problem of ground water level and nitrogen fixation . I will not say that its a great idea because its not sustainable .

[@sonuyadav1182]

Sorry i commented earlier , you have address that problem

[@miheedd]

Водопроницаемый бетон можно использовать только в теплом климате. Иначе вода разрушит всё покрытие при частых циклах заморозки и разморозки. В многих странах даже непроницаемое покрытие не выдерживает таких воздействий. Днем тепло, лёд растает, а ночью замерзает (увеличиваясь в объёме и разрушая покрытия).

[@rgbii2]

Definitely interested in videos on flooding and ways to handle runoff. I live along the Colorado, and heavy rains around the Austin area flow by my place, and when it's really bad, flows over my place!

[@bashisobsolete.pythonismyn6321]

i enjoyed this one. i like this subject matter. BTW, it is more correct to say MANMADE. that's an actual meaningful word. don't be that guy; say MANMADE.

[@jameslmorehead]

A few years back, I called around to the local concrete companies to price out delivery of permeable concrete for my driveway. None of them knew what it was. I literally had to give them the full recipe and wait for them to call me back a day or two later with a quote. One big cost increase between regular concrete and permeable concrete is the rock. See, the rock for permeable concrete needs to be washed of debris, and within the size range of 3/8" (9.5mm) to 1/2"(13mm). Regular concrete can take the dust and debris and can have a size range of 1/4" to 3/4". The large size range actually makes the concrete stronger.

[@gr8dvd]

”give recipe" Not surprising as ALL building trades (and suppliers) are notoriously un-innovative.

[@hunterschulte9225]

What was the $/ cubic yard? Would be nice to consider for LEED projects but usually budget is the limiting factor.

[@wijayatan7870]

well they are robot minded worker is like that.. not inovative n scared new things

[@justgonnagetbetter1037]

@@wijayatan7870 the robot workers that make, install and maintain the roads, sidewalks and parking lots that you like to drive and park your high horse on aren't afraid of your imagined fears. Maybe if you had made it to the end of the video you would have noticed that Grady said that this is new technology that's hard to implement. Which means 95% of your concrete suppliers will probably not have heard of, let alone taken the time to learn the recipe for a concrete mix that maybe gets used .01% of the time currently.

[@teemun3979]

@@justgonnagetbetter1037 Exactly, not to mention the average employee only cares about what their boss tells them to care about in regards to their job. What kind of geek of a construction worker is going to be low on the managerial totem pole, but still be the first one to know about a new technology in their business?

[@chriseggenberger]

When I used to work for a sewer company I had a job inspecting some manholes at companies parking for potential blockages. The parking lot ended up flooding 1-2 feet with cars in the lot. It turned out when the building was renovated for office space they had to include a second detention area, but were restricted by how much space they had. Come to find out the last manhole had a 6inch outlet pipe. The engineers made the parking lot the second detention pond!

[@gavinli1368]

I’m sorry what? Did I read that right? How in the world did a design like that get approved?

[@Lady-Lilith]

Some codes do allow ponding in parking lots to account for detention, but I think it's limited to 6-inches of standing water limited to a certain percentage of the lot and it cannot block ADA paths. I've only seen it done a couple times, and generally warehouses will use areas by loading docks where people never walk on the ground.

[@rkf053fitz]

@@gavinli1368 That's actually a common strategy. You'll notice a lot of parking lots are a bunch of small basins that act as extra storage. You can increase storage by using larger pipes too, with a smaller pipe at the end to restrict the outflow. You'd often design the lot grading with tipping points that would release excess water if the system gets overwhelmed.

[@jpaugh64]

Well, it's better to flood the parking lots than to overload the drains and sewers.... I guess.

[@Antix619]

As an inspector, the State of California does not understand this. Just gives a blanket credit for the project if you use pervious concrete or detention/retention basins. No determination of if it's practical or engineered to make it practical. Can't tell you how many times I've seen 4-5" of porous/permeable concrete sitting directly on native clayey subgrade. I always ask the contractor and Owner " Why even bother with the permeable concrete?" Answer: Because the government paid for it.

[@grassgeese3916]

i wonder how u stay sane!!!!! Woww

[@Allan_aka_RocKITEman]

California -- what a concept...🙄

[@Nanomachines5on]

Sounds like California! You can’t make this stuff up.

[@alanleuthard2689]

I've engineered several zero sum BMPs at client request due to CA policies. I literally have to spend design time making sure the useless basin I'm adding doesn't make things worse. It's usually an interesting exercise when taken by itself, but very cringey as I'm signing the plans.

[@ChiNguyen-vw9pi]

is it at least better than not having permeable concrete?

[@Bundesligahoffefan]

Note: permeable asphalt is usually used whenever parts of the autobahn network in Germany are being upgraded. It’s NOT just used for parking lots, at least here in Germany. By the way, it’s awesome to drive 180(km/h) on permeable asphalt when it’s pouring rain

[@harmg937]

In the Netherlands nowadays all our highways are made from permeable asphalt. Mainly to prevent water splashing during rain.

[@hanzzel6086]

Must be nice, not living in a frozen hell scape for half the year. It lets stuff like this survive for more than a year.

[@iyt6407]

@@harmg937 Also because it reduces road noise with about 5 decibels.

[@simo007_d7]

Also here in Italy permeable asphalt is used in highways and other busy roads such as “national roads” that are often 2 or 3 lanes wide depending on the area. Also parking lots here are not as big as in America so they're usually made out of normal asphalt, or in some cases as shown in the video they're made with those concrete squares with grass in the middle so that they can flush water right into the ground

[@oldtimefarmboy617]

I live in a semiarid part of the country so heavy rains and the runoff that goes with it is not a big problem. A few years ago a business built a new location using permeable material in the parking lot. One of the first things they did was to build a huge cistern that was reinforced to hold a lot of weight above it. When they started on the parking lot they laid an impermeable layer where everything was sloped to the intake on the cistern then topped it with permeable concrete. Now when it rains the run off from the roof and sidewalks flows to the parking lot and then to the cistern. The cistern also has a pump so that they can use that captured water to irrigate their landscape. The landscape is xeriscaped with native plants that do not require a lot of water, so the water from a good rain can last a long time before they need to make use of city water.

[@natesmodelsdoodles5403]

nice.

[@angrydragonslayer]

I was actually thinking of this one, why would you put a stone reservoir under it rather than an impermeable layer that leads to collection drains?

[@cinnamoncat8950]

@@angrydragonslayer im no engineer gaming but i think it might be so that the water can go into the ground instead of into drains which just lead into already over encumbered streams

[@angrydragonslayer]

@@cinnamoncat8950 i forgot that part of the video.....

[@TheMrVengeance]

Wow, neat. Learned the term xeriscaping now. Cool concept.

[@mongoose1618]

In some parts of India, our local PWD keep deep holes in the middle of the roads to collect rain water to slowly replenish the groundwater. We call them pot-holes, and i think its ingenious. It also slows traffic thus increasing safety for pedestrians. Unfortunately, It has received a lot of backlash from vehicle owners and old people.

[@moogle68]

underrated comment😆😆

[@CrystalClean333]

😂😂😂

[@samuelalalade2075]

🤣🤣🤣🤣🤣

[@jonboy545]

They have started paving large sections of interstate here in North Carolina with this new asphalt that the water just soaks right through. The impact in safety while driving is mind boggling. WIpers can almost be turned off completely. You don't feel like you're going to die every time you get behind a semi and all the water they throw off. It is astounding the difference it makes.

[@IntrepidInfinity]

I wonder how they're dealing with structural weakness problem. Might be worth an investigation

[@Twiggy163]

@@IntrepidInfinity no need, the Netherlands have paved their motorways with ZOAB (Dutch abreviation for very open asphalt concrete) since 1995. The top layer is exactly as @jonboy545 describes, it also reduces road noise and deforms less. So theres no ruts in the road. Under the permiable top layer, there is an impermiable layer to make sure the rainwater runs off to the side and doesnt affect the foundations of the road. The downsides are: shorter lifespan for the top layer (about 10 years vs 15 to 20 for regular asphalt), more sensitive to freezing (due to water freezing up inside the open layer, it will crack much faster) and newly layed open asphalt privides less friction which results in a longer brake distance. This gets better over time.

[@frenchys_prospecting]

It also helps regenerate the water table in built space areas

[@LeahLuciB]

How do they deal with ice? I'd fear that the water would expand in the gaps and break the pavement up

[@stevenschnepp576]

@@LeahLuciB By driving more, so the vehicle exhaust emissions contribute to global warming and prevent the ice in the first place. Modern problems: modern solutions.

[@JustJoshtheDad]

I'm an DOT inspector, and on a DOT job,we recently used a permeable asphalt pavement, (open graded bituminous base), as a base course for concrete pavement. The permeable material was placed on top of 8" of agg base, then 4 inches of permeable base. then 9 inches of dowel jointed concrete. the permeable base had edge drains running along it, which then drained into the storm sewers. this was used to help keep water from deteriorating the concrete from underneath. The area had a history of bad soil, and holding water. This is starting to become a regular thing in Oklahoma. Another major job in Tulsa recently used permeable concrete in roughly the same configuration. I think the thought is, the concrete pavement above it, helps prevent alot of the surface issues it has, and the pavement also distributes the loads on the permeable concrete, so it doesn't fracture. Long time watcher, and alot of your videos have to do with Jobs I inspect on a daily basis so it is pretty cool learning more, and just being able to appreciate the engineering. thanks for all your videos.

[@The_Original_forresttrump]

Sounds expensive and prone to freeze/thaw damage?

[@LeahLuciB]

How well does it handle ice?

[@JustJoshtheDad]

@@LeahLuciB it tends to ice up a little sooner. Air voids make the pavement cool faster. Soo yeah more ice

[@h8GW]

@forresttrump.7910 Still, if the water can drain out, ice wouldn't form in the first place. Also, the cavities will be mostly air, so any ice that does from has room to expand.

[@johanprb357]

The lack of googly eyes made the topic hard to understand.

[@KingJellyfishII]

Instructions unclear, accidentally poured my concrete onto the ceiling due to lack of googly eyes

[@vaderconstantine]

agree

[@gensuave1]

That, and his alliteration of the letter 'p.' I found myself bracing for the next word and couldn't focus on what Grady was trying to teach.

[@_Solaris]

Oh yeah... no googly eyes

[@seanriopel3132]

His tongue was filling that role.

[@Aaron.Reichert]

As someone who lives in an area that turns into a frozen hellscape for a quarter of the year, I have always been skeptical. It doesn't help that it is usually some viral Facebook post that leaves out all the important stuff like what is below the pavement. Thanks for your explanation of what is going on.

[@drowningflamingo]

Grady, I love that you use the same music for every video. It’s so comforting and familiar. I’m so grateful that you’re in this world with the patience to see the marvel of civil engineering and I’m grateful that you have enough patience left over to teach what you know. Life is hard for so many reasons right now and I’m just so grateful for all these videos you’ve made; they make things a little easier and they remind me of the joy of curiosity and learning.

[@robertpierce1981]

I agree with the repetitive music. I like it.

[@russrags6274]

I was just thinking the same thing, the music is perfect always

[@roccobastone1441]

probably helps a lot with editing and avoiding copyrights too

[@Kio.O]

This very comment has ruined my whooole interest in his videos entirely lol

[@tylerc3576]

@@Kio.O ? Get a grip.

[@chrisgoosebeck]

I'm curious what the affect of freezing and thawing cycles for colder climates has on these designs in addition to long term collection of organic material and the potential for reducing the efficiency of flow.

[@Hellsong89]

Was thinking of this too. I have couple of places that could use this kind of setup, but it needs to be long term solution with minimal maintenance or least be able to clean it. Maybe slaps or tiles that can be lifted and underside reservoir be flushed and fine material separated every decade or so in private house yard.. bit more often on commercial area.

[@BillyBob-fd5ht]

pretty sure ice would win or to keep it from freezing salt or organic beet juice

[@mehere8038]

yeh, the organic matter is what I can't figure out how it works with. Surely if the onlyl thing missing in the mix is sand, then over time sand & silt & dust is going to clog it up?

[@oldgrunt5806]

Worked for Public Works in a major city in Minnesota, they tried this with permeable concrete many years ago. Did not work as it got plugged up and in winter started to break up. Wound up replacing it with regular concrete @ 8 years later.

[@challenger3603]

The other thing is in the northern climates you have to use anywhere from 4-8 times the salt to keep the road open. As the water drains it will freeze and start to bubble crack the road. You have to drop a 600 application on this type of road to keep the water from freezing where normal roads are about 200s. An 800-1200 in a heavy storm where a 400 to 600 is normal on regular pavement. This road would be best in places where the ground never freezes and temps never drop below 35 degrees.

[@bdbgh]

Steel gratings are starting to be replaced with concrete gratings (not permeable concrete) in my country, since it gets stolen every now and then for scrap metal. The issue is the hazard more than the cost for replacement of the grating. This permeable pavement seems helpful for reducing the amount area needed for holes to divert water to the storm drain.

[@toohoney8674]

What country do you live?

[@TheRogueRockhound]

@@toohoney8674 Imma say eastern europe

[@josephvanname3377]

Cop: HEY WHAT ARE YOU DOING? ARE YOU STEALING STEEL? Bad guy: No. I am just working out.

[@sergarlantyrell7847]

Imagine walking through a puddle where a steel grate is meant to be, only to fall right into the flooded hole because some unscrupulous person pinched it.

[@emilianozamora399]

@@TheRogueRockhound eh it sounds like something they'd do in an undeveloped south american country

[@StefsEngineering]

Ah the good old ZOAB (as we call it in the Netherlands). Pretty much all highways and a part of the urban roads are made of it. In new urban area's all pavements and most of the roads are made permeable with signs not to dump sand or limitations on the weight of vehicles that enter an area. Oh ZOAB stands for "zeer open asfalt beton" or directly translated: "very open asphalt concrete" Addition: I looked into it a bit more and it seems that the Netherlands started to use ZOAB in 1995, the newest versions are way more durable and a lot quieter compared to the earlier versions and especially in comparison to normal asphalt or concrete (-6dB).

[@pietvanvliet1987]

Brady: Makes video about water management. Me, when realising the solution is something the Dutch are doing for decades: Quick! To the comment section to find other Dutchies! Has anybody yelled "gekoloniseerd" yet?

[@StefsEngineering]

I looked into it a bit more and it seems that the Netherlands started to use ZOAB in 1995, the newest versions are way more durable and a lot quieter compared to the earlier versions and especially in comparison to normal asphalt or concrete (-6dB).

[@StefsEngineering]

@@pietvanvliet1987 Well hi there :P

[@mukrifachri]

I think it's different though... They just put the water to flow within the surface layer. Benath the surface layer it's still the fairly impervious HRA / AC / SMA right ?

[@StefsEngineering]

@@mukrifachri Depends on the loads it sees. Right lane on a highway needs to be a lot tougher than a sidewalk. (obviously) the sidewalks and roads in front of my home do have the shown layering of sand, gravel with a topcoat of permeable asphalt or "clinker bricks" that are also very common on sidewalks and roads. en.wikipedia.org/wiki/Clinker_brick

[@Langevloei-NL]

Seeds get in the little holes and presto grass starts growing, even trees. Roots are very strong. Also, water inside the holes freezes in winter and expands, breaking the asphalt/concrete apart. We use ZOAB (Zeer Open Asphalt Beton) in The Netherlands for many years on dikes and elevated highways.

[@grantflippin7808]

It also accelerates road destruction and has a higher repair costs

[@hockeylance36]

Perfect for Phoenix where it never gets below freezing

[@mattalley4330]

​@@hockeylance36 Freezing temps are extremely rare in Phoenix, true enough, but weeds taking root in such pavement could still be a problem.

[@Nuggie_terpfessor]

I would figure they’d get clogged with dirt as well.

[@MartVan]

@@grantflippin7808 It doesn't you just resurface the surface every few years. That's how they do it in the Netherlands.

[@Orrinn123]

I love how Grady always looks like he's so excited to teach us something

[@MrMysticphantom]

I love the fact that you not only covered the concept in detail, and its important variables/parameters, but you also made showed where its beneficial, and where it should be avoided for use and why. Usually its always just one or thr other

[@michaelesposito2629]

LOL he was trying so hard not to smile while saying that “pave parking lots” song lyric 😂

[@RyanRiopel]

Big Yellow Taxi by Counting Crows, in case anyone was wondering

[@bidaubadeadieu]

@@RyanRiopel no no no, it's by folk legend Joni Mitchell! Counting Crows just did a cover

[@RyanRiopel]

@@bidaubadeadieu thanks for the tip! I grew up listening to the crows version on the radio

[@Lady-Lilith]

That smirk on Grady's face had me cracking up.

[@Mrcaffinebean]

It’s so heard to say it and not sing it 😂

[@sethyuikora2]

Moved into a house where the previous owner lined the back yard with bricks. The bricks form enough of a seal to collect water in certain places and even makes it into a ground-level room sometimes. My next major project is to remove all of the bricks to fix help with that issue, but I was thinking of using home-made porous concrete blocks (similar to the circular one in this video) as a method of displacing the water while maintaining an earthen look to the yard. Thanks for this explanation as I would have no irrigation or reservoir to get rid of the excess and would've ended up wasting a lot of time and resources on it. Though I'm sure it would've helped to some extent, the cost and time wouldn't warrant the result.

[@Alex-us2vw]

The retention “ponds” we have around here don’t discharge storm water back to the storm sewers. They are usually in green space and just hold the water to filter into the ground over time.

[@kenoliver8913]

That depends on climate (ie how much precipitation), topography, soil type and how much free land there is. As the video mentions storm water management systems vary hugely according to local conditions. How useful permeable pavement is varies according to these - in some it will be absolutely ideal, in others useless.

[@corthew]

Permeable pavement works by allowing the water from melting snow to seep into it so that when it refreezes the entire pavement becomes gravel which can be more easily removed with a loader.

[@ryanmcgowan3061]

Porous paving clogs very rapidly, even with sweeping, and especially in areas prone to dust. A better alternative is to use normal paving with linear grates over a deep bed of compacted crushed gravel. The grates drain into a perforated pipe along the aggregate bed. At the far end, you can do another perforated pipe for an outflow of cleaned water. The storage volume is determined by the outflow elevation to the bottom of the aggregate bed, which should be completely flat. For larger volumes, you're going to add Stormtech chambers.

[@slitor]

Like a spread field for your septic or a drip irregation system? Cost and maintanace would be a huge issue though.

[@ryanmcgowan3061]

@@slitor There's a lifespan to it, but a well-designed system will last decades. Proper pretreatment, catch basins, cleanouts, and soil conditions will have a big effect on longevity.

[@kdm28]

Had that the clogging problem in NM. Rural area with agriculture land and dirt roads. DOT bought a vacuum sweeper for maintenance but it's difficult to keep up

[@SmallSpoonBrigade]

@@kdm28 The lesson there is that not every technology can effectively be used everywhere.

[@vadenummela9353]

As a Finn. This looks like a very "californian" solution. Its "the perfect replacement" except in 90% of cases. In Finland every single one of these installatios would fill up with water and crack from freezing every year. Unless theyre like heated, which means even more cost and constant supply of heating, only near buildings.

[@richardschofield2201]

Nah, we use this stuff in the UK and it freezes in the winter a fair bit. I've specified permeable concrete a few times. It's permeable so when the water freezes it can expand through the pours and doesn't crack. Normal concrete is a problem as water can freeze into cracks with nowhere for the water to escape.

[@eklectiktoni]

You'd be surprised, it actually works in a variety of climates. It's starting to take off throughout the US.

[@aVeryIntelligentDog]

I work in construction for a company that is certified to install permeable asphalt and concrete (you actually need certification to do it where I live). Permeable asphalt/conrete still has a lot of room for improvement and there are many reasons why you don't see it more often. 1: Cost: It is anywhere from 3x - 5x as expensive per square meter, due to a higher quality aggregate being used, and a more time consuming installation process. 2: Maintenance: Sweeping alone will not prevent the asphalt/concrete from getting clogged, and it inevitably will get clogged over a certain period of time. A powerful pressure washer helps, but it would require a huge amount of time/water and it also just pushes a lot of the dust into the lower stone layer, which can become clogged over a much longer period of time. However, the pavement probably won't last long enough to experience that because- 3: Durability: Permeable asphalt/concrete is simply not as durable as conventional asphalt/concrete. The older it gets, the more easily it will crumble apart, and you will start seeing individual rocks breack off pretty quickly if the surface gets a lot of traffic. Permeable pavers work better in terms of drainage but they're even more expensive and more costly to maintain. It's a great idea but it will take some time before we could improve the technology enough to be practical for high traffic roads.

[@arthurbdt2329]

How can you improve asphalt technology ? Porous asphalt has existed for a long time and there has been no improvements.

[@zoravar.k7904]

@@arthurbdt2329 There have been plenty of improvements to durability and noise performance. Just look at how far the Netherlands have gotten since they started mass adoption of permeable concrete around 1995

[@shannonlove4328]

I’m surprised that permeable pavement doesn’t clog rapidly. I grew up in West Texas were dust is omnipresent, so my intuition is that any small pore material would be quickly infiltrated and blocked. How does this material’s porosity age? I would assume that under real world circumstances it would grow progressively less porous and eventually seal shut. What prevents that?

[@StefsEngineering]

In the Netherlands (mild climate quite wet but nothing too crazy) it has a lifespan around 11 years. The new stuff obviously works a lot better but it is allright after 10 years.

[@TomServo3006]

As a civil engineer in the NE, we avoid it for this very reason. Salt and cinder in the winter ruins permeable asphalt. Not sure about concrete, we try to avoid that altogether for cost reasons. Also the asphalt is, as he mentioned, a special mix that costs more to produce and place so in the end it’s just not worth it except in rare circumstances.

[@leddaudet2350]

And another concern would also be mold growing inside the pores of the concrete

[@TomServo3006]

Led Daudet why’s that?

[@rapierlynx]

You have to vacuum it regularly and use straight salt (no sand or grit) for deicing. Not that sand melts ice anyway... One advantage is when it's warm during the day and cold at night, slush seep through instead of refreezing at night.

[@haroldwong9235]

"pave paradise to put up a parking lot" smooooooooth 😁

[@l0renzz0]

counting crows reference

[@RG-3PO]

Or Joni Mitchell , Big Yellow Taxi reference

[@sarikatimmi]

jack johnson

[@RaymondHng]

@@l0renzz0 kzbin.info/www/bejne/b2XFlYCJeMmqaJI

[@l0renzz0]

@@RaymondHng thanks, first thing I did was searching for Joni Mitchell from Robert G's comment. I never knew Counting Crows did a cover

[@intrepid_wandering]

Channels like this are worth their weight in gold. A true asset to humanity.

[@digvijaysinghrana3351]

During my childhood I had this idea of a road pavement which will allow water to seep into the ground instead of directing it to sewage. And I'm blown by the thing is that someone made it.

[@Piracanto]

Very interesting and wholesome with the kiddo! In Mexico we use the poor man's alternative: Gravel.

[@RoySATX]

I havent been to Mexico in some time, but when I was there I saw a lot of paving stones in use and being installed. Every time I went I saw the same areas under constant work. As soon as the pavers were laid they started falling apart, so it was a never ending work site. At the time I considered this a somewhat insane idea, but looking at it now I think it could be modified in such a way to be a practical design method.

[@mayoofm6049]

xDDDD

[@andym7165]

Mexico roads be like: ------___--_--_-^_^>___------^---^

[@jeffreypierson2064]

Your results may vary, depending on type of soil. Add water to the subsoil and you may get mud. Then the car drives on the gravel and gets pushed into the mud. Now you have spent money on gravel that has disappeared into the mud.

[@truckernation7886]

Cobblestones

[@iturnacupover4139]

You know the days gonna be good when practicle engineering uploads

[@dabonkus]

yoo this dude just turned a cup, future engineer right here!

[@ianjung2683]

I'm doing a project on stormwater runoff in my school, and this video really helped me to understand permeable pavements. Thanks!

[@gur262]

Would be cool to hear about noise barriers next. Reflective, absorbtion, earth, bushes, concrete, etc

[@wich1]

I was wondering about this when watching your potholes video. Here in the Netherlands permeable pavement called ZOAB is quite famous, even many “regular” (non-engineer) folk know it although they often are misinformed about the details. ZOAB is Zeer Open Asfalt Beton, or very open asphalt concrete in English. In contrast to what you said this is actually heavily used on regular roads and highways that receive medium to heavy traffic. I wonder whether we have much more road maintenance because of it and/or whether we have found ways to fix the problem.

[@ietsbram]

According to dutch state standards we replace zoab every 11 years instead of the 19 for "normal pavement" assuming both are under a lot of normal weight car trafic

[@ahmedyassir5569]

I think it’s more of a safety concern; to prevent vehicles from skidding considering how much it rains

[@staalman1226]

@@ahmedyassir5569 It's probably more to prevent floods or rising rivers than for skidding (Misspelled "rising" at first)

[@cghoward70]

The Netherlands can’t afford not to. A large portion of the country is very close to or below sea level. The flood plane is everywhere.

[@dascandy]

Congrats on the little one! In the Netherlands most of the highways are made from permeable road surface. Come take a look when you can! It's a nice surprise every time I drive home from Germany or Belgium when you cross the border, when it goes from a wet road to a highway instantly.

[@FurnitureFan]

Maybe it makes a difference that the Netherlands is a flat country? I grew up near mountains and when the local town roads flooded, everyone bypassed the areas by driving up through the mountains.

[@iyt6407]

@@FurnitureFan No it works everywhere, there are also more hilly parts of The Netherlands where it works fine. In Germany there is a mountainous part between Frankfurt and Munich where they applied it and it works very well!

[@williamzycinsky4720]

I'm always impressed by the fact that he can a four-minute intro into his actual topic of the video, the most interesting thing I've seen that day. Keep up the great work man.

[@pb730c3]

This was tried for a parking lot in Lansing, MI. It has recently been replaced with traditional asphalt. It didn't do so well with our freeze/thaw cycles and plowing. They ended up patching parts with concrete but It basically turned into a loose gravel parking lot.

[@THEmickTHEgun]

This channel is one among a few sources of content and information that encouraged me to hopefully study engineering next year. Thank you, you are inspiring many of us.

[@asdffjsdjasd]

Grady saying "OG" made my day. Also, congratulations! You have a lovely family.

[@vMixMasterJayv]

Ayyye That Big Yellow Taxi reference! Don't think I didn't notice! I love your videos!! Keep them coming! The format and production of the videos is fantastic and your visuals really help me to understand things love your work man!!

[@drockjr]

Most STEM videos are boring, long, complicated, and just terrible to learn from. With yours, I can easily smoke a bowl and drift away to your soft, knowledgeable voice, and the distant audio track of dreamland. -----All while actually learning and retaining the interesting subject matter. Like your video on Weirs or this porous concrete. I don't think anyone woke up this morning thinking *hmm, I really want to know more about this..* So kudos for engaging us, entertaining us, but more importantly taking your time and effort to reach those around you. You truly seem to love the subject matter and it shows. Thank you for all you do!

[@mariodidier001]

That bridge shot at the beginning clearly shows how changing lanes slows down the traffic and produces a wave of slow downs.

[@LadyAnuB]

It's traffic from the western half of the Bay Bridge, westbound going into San Francisco.

[@watchandjewelryloft4713]

I absolutely hate that we don't teach and strictly enforce this simple task. Not only is it ridiculous to deal with, but who knows how much fuel it wastes, and with that emissions released into the environment. Add to that, many traffic signals that are extremely inefficient.

[@RoySATX]

Lane changes only slow traffic when the distance between two vehicles is less than a lane change requires and space must then be willingly granted or forcefully taken. And since both the person currently occupying the space and the one wanting to occupy the space assume the other is in their way and impeding them unnecessarily they end up jockeying position and impeding all the traffic behind them, further compacting their following distances. Lane changes aren't the problem, they are a necessary function of traffic. Impatience and not allowing proper distance between vehicles is the problem, and that is a phsychological problem more than an engineering problem. If appropriate following distance was maintained to allow lane changes, especially at ingress and egress points and at bottlenecks, traffic jams would cease to exist in most cases. Traffic would slow down, sure, but not come to a complete stop. Instead of having horns to blast at othes, vehicles should have horns that blast the driver whenever they tailgate.

[@jonathanorlando1294]

Grady finally got around to talking about grates, that is great!

[@sandrom.1992]

I was very happy to see such an excellent and high quality video about this one. I'm writing my master's thesis about reinforcement of road shoulders with permeable pavement. It's a very new topic for our university. Fun fact here in germany permeable pavement is called "open-pored concrete" (offenporiger Beton).

[@elementalcore3454]

This channel reignites my motivation to try for a pre-engineering major in college. I am currently a geology major, and I can pair that very well with engineering. Funnily enough, I decided to watch this because of my geologic knowledge; a permeable material for infrastructure is a game-changer for mitigation of dangerous geologic events associated with water (which is a _very, very large portion of geology_ ).

[@kdm28]

Go for it I'm s civil engineer and many PEs where I worked at the DOT has geology degrees

[@skullhelmet1944]

I wonder how many kids watch this channel and eventually become engineers? I would bet it's a lot, he makes it seem so fun and interesting :)

[@sweepingtime]

And the best kind of engineer, the civil engineer.

[@tacocat1714]

It’s a lot better than School’s teach it, they just throw a paper packet at you and say something like: “Here’s your packet it’s 15 pages, test tomorrow good luck!”

[@meneldal]

@@sweepingtime I wouldn't say it's the best, but there's definitely a lot of fun stuff in civil engineering. Also probably easier for people outside the field to understand because the scale is close to us. Most people see electronics as just magic they can't understand, but a bridge, everyone can picture it.

[@NimithChanceson]

Learning engineering is fun. Dealing with contractors is not

[@benbarker8154]

My son is studying engineering at Miami University at Oxford, Ohio as a direct result of this channel. We started watching these videos together when he was in high school. He made the decision to be an engineer in his junior year.

[@aniketshrivastava4908]

I was actually enjoying the ending advertisement part..

[@theskig]

Me too.

[@saleplains]

@@theskig i liked when she made fun of his knife work

[@kevinjanicki3973]

@@saleplains Tell me when to start recording.

[@chickey333]

Crushed pottery cull is an ideal stone reservoir material if you can get your hands on enough of it. It's very open graded, it's very angular it drains instantly and it is extremely stable. It makes a very good underdrain for any purpose.

[@CupolaDaze]

I remember watching this video when it came out. Now the company I work for has done two permeable pavement parking lots. Large excavation for the subgrade rock to filter the water. Solid concrete baffles to section off the underground, and pvc pipes to facilitate that water leaving if it can't permeate the soil.

[@thestructuresguy8355]

The first time l learned about permeable pavement when I was a kid I thought it was some kind of trick or magic but when I studied it more it turns to be another way of using concrete. Thank you for you the great video as always

[@g.m.2427]

It's still magic, only now you know how it's done

[@firearmsstudent]

This video is brought to you by the letter "p"

[@ameyd3728]

Public money

[@VeNoM0619]

You see his Pink Pants during the Paid Promotion at the end?

[@honorarymancunian7433]

Someone needs to do a version where the video speeds up 1% every time a syllable beginning with a hard P is uttered.

[@MrMatteNWk]

I think I'll have to take a "p" kzbin.info/www/bejne/nqu6lYGLnLSneKs

[@syedammartahir6395]

Grady you are an awesome person. Your way of explaining is awesome. You look so calm! Any engineering topic I don't understand, your videos help me through it. You would make a great professor and your students would be lucky to have you as their teacher

[@reigyst]

Also a callout at the opening 0:14 to Hartford CT's skyline :). Very happy to see it making it to this channel

[@jaysonl]

"Special considerations" in colder climates, indeed. My first question when I saw this video was "Huh? How is permeable pavement not ground into gravel when ice intrudes?"

[@weldonyoung1013]

The salt destroys it before the ice can form. But then there is beet juice.

[@servant74]

Some additives can add an 'elastic' quality to the concrete. It doesn't solve the freeze thaw issue, but it helps.

[@garcjr]

Most surfaces of permeable pavement I've seen are overlayed on top of asphalt or concrete. The permeable pavement is used as a wearing course.

[@weldonyoung1013]

@@garcjr , sound like you are pointing to a different produce like "top coat" or "chip seal" which usually have a short 'life-span' and are used to extend the useful life of the roadway. Some may only extend the roadway for a few years before complete maintenance is needed. The "chip seal" would look very much like permeable asphalt, but without a means to drain through the bottom will not function that way.

[@garcjr]

@@weldonyoung1013 What they pave here usually on highways is a one to two inch layer of rubberized asphalt which is a permeable pavement. It's placed on top of a base layer of asphalt or concrete. The DOTs here strip it down about every ten years and replace it when the pavement looses it's ability to reduce noise and drain water. The water drains into the rubberized asphalt to the concrete surface below. It greatly reduces [eliminates] the spray effect from cars. The soil here (in Arizona) you wouldn't be able to lay the permiable pavement directly on the ground the soil's too dry and would reduce the lifespan of the surface above.

[@Colossus01]

Don't think this would work that well in Norway, but it would definitely be interesting learning more about this. Especially how one would tackle frost heaving, subsurface erosion, and what-not.

[@NameNaameNameeNaamee]

Congratulations on your little engineer! It shifts your life quite a bit doesn't it? :) Godspeed for you and your family! And - as always - this was a fantasticly well made video!

[@martindejong3974]

In the Netherlands we use permeable roads, that help when driving in the rain. Our solution is called ZOAB (Zeer Open Asfalt Concrete Very Open Ashphalt Concrete) It also keeps the ground water level up. We also use very stick salt during days it freezes. we have been doing this for say 20 years now.

[@yannicmeyer421]

Congratulations on becoming a dad! Great vid as always :-).

[@erik365365365]

“Do you think my camera is going in slow motion or are you just that slow at cutting shallots?” What a whip

[@JKiler1]

I always appreciate your in-depth and practical approach to engineering topics. Learned a lot in this one as usual.

[@Zhane853]

I really appreciate your videos, Grady. You do such a great job of explaining things in a way that's easy to understand.

[@lewisdoherty7621]

In the past, road paving had consisted of bricks which were cemented together creating an impervious surface. Rather than the concrete and asphalt with holes, maybe the level below should be packed with gravel and on top brick pavers with spacers separating and wedging them in. While some plants may try to grow in the spaces and trash might collect, I don't think they would be major problems. What I particularly like is such a structure can be easily taken apart for utility work or repairs to it as well as cleaning out the gravel if it silts. I'm sure it will be calculated to generate a flow to flush it out, but much of it likely will silt. Railway ballast is designed to flush itself out, but ballast cleaning machines have to still be used. My paternal grandfather would refer to paving bricks as "Irish Confettii," because when fights occurred, men would pull up the road pavers and hurl them at each other.

[@trcostan]

I would argue that bricks are the OG of permeable pavement!

[@RAkers-tu1ey]

Too true! But, have you ever seen the maintenance needed for brick and cobblestone paving? Talk about rough roads!

[@danielloup9373]

R. Akers I’ve seen what it takes to fix both concretes and I still think cobbling is best for most residential roads.

[@comcastjohn]

Great channel bud. Thank you for sharing. Hard to find quality and educational stuff on tv or anywhere now days.👍

[@maulerrw]

Hey! I once worked at a factory making permeable pavement some years ago, it was very neat stuff. It used a specific gravel mesh size and a mix of resins and fibreglass chaff for strengthening. The whole lot was mixed in a giant mixer then compressed and vibrated into moulds, then baked in an oven. What came out was pavers as strong or stronger than cement pavers that allowed water right through it. Ratios were crucial. Too much resin and it would goop up the mix and look bad and not work correctly.

[@luigigaminglp]

Just watched this video, immediately got an idea: What if we keep the road itself impermeable, and make the sidewalks permeable entirely - since if there is little water to begin with, that will just drain as soon as it hits the sidewalk border, and if there is quite a lot more water the drainage effect also increases since more water = more permeable surface area... And since the sidewalk doesn't require to be nearly as powerful as the rest of the road...

[@BlackViperMWG]

Hope you'll make video on anthropogenically modified riverbeds versus revitalized, natural riverbeds, where rivers are allowed to meander and carry gravel.

[@gareth-stuartogg7887]

Best thing about practical engineering is that when a video is sponsored it's mentioned in the title card briefly then in more depth at the end of the video. The way sponsored videos should be!!! The content is always first on this channel and many more KZbinrs need to take note of Practical Engineerings approach to quality and viewer enjoyment

[@JAF30]

Thank you for this video, this has given me a lot of information to a number of questions I had on permeable concrete.

[@Mr.Adequate]

Every time it rains there is about half an inch of standing water on my school's recently installed "permeable concrete" thanks to our concrete science technology majors.

[@TheOfficialOriginalChad]

“Some may call it the OG permeable pavement: steel grating” *subscribes

[@konman36]

Back in college I sat in on a Civil Engineering lecture at The University of Michigan with my GF at the time (I was a nursing student). Although I had zero interest in Engineering, the lecture was about porous concrete and I never forgot the lecture.

[@aldenconsolver3428]

Would really enjoy a longer series of videos on this more nature friendly surface treatments. This is an excellent start.

[@zoogoo404]

I've never been so early. Always appreciate your content PracEng!

[@jasonhalljaxyt]

8:40 CONGRATS Grady

[@BADALICE]

I managed a 5 story 52 unit apartment complex. The second floor had a community center with a large outdoor patio with tables chairs bar b que planters with trees as well it had a play area with an elaborate play structure. The play area had a rubberized mat system for the floor. The out door area had a brick retaining wall about 3' high that was covered with a yello gold cap stone that over hung each side. This patio area was directly over the first floor storage area. The storage area contained chain link cages; one assigned to each tenant. When I took over management there was a problem of water coming down the walls in the storage area directly under the play structure and causing damage to tenants belongings. There is a double wall in this area. The inside dry wall a gap and the outside brick wall. The problem was reported to the builder and a crew was sent to fix the problem. The first attempt was tearing up the pads in the play structure along the perimiter placing flashing around the perimiter and sealing it. The next rain came along and there was still serious flooding in the storage area. A crew was dispatched a second time to do the repair. This time the entire floor area of the play structure was removed. Rubber skin was placed and sealed with hot asphalt. The rains came again and still there was flooding in the storage area. Nobody could figure out where the water was coming from or how it was getting into the building. Part of my duty as manager was to maintain the building keeping it clean, watering the plants on the patio and hosing down the patio was daily. One day while watering I had the hose going at a low flow and I laid the hose on the retaining wall yellow capstone. I glanced at it and noticed the water coming out of the hose was going right into the capstone and vanishing. The light bulb went off and I went downstairs to the storage area to check and sure enough water was coming into the storage directly below where I had laid the hose down. I reported my discovery but was not around to see how the problem was resolved. All that work for nothing, and the problem (porous concrete) was sitting there right in front of them the whole time.

[@drewdoestrucks]

They paved a portion of highway near me with permeable pavement or cement and noted a reduction in accidents during inclement weather, which was attributed to less hydroplaning. Unfortunately, the permeable tarmac was apparently significantly louder than traditional road material and local residents complained about the additional noise. The section was replaced with non permeable materials.

[@Ally-Oop]

“When you pave paradise to put up a parking lot” he looked so adorably smug with that reference haha

[@MrEazyE357]

I met them once in a TCBY Yoghurt in Nashville when I was in 7th grade. The lead singer was a dick, especially considering we were 5 kids just telling them we liked their music. This was like 25 years ago btw.

[@XavierRaphael]

Video: “Includes paid promotion” Me: ok KZbin: here’s an AD!

[@randommcranderson5155]

the "paid promotion" disclaimer is because many youtubers were slipping in promotions without letting their audience know they were being paid to promote something. The disclaimer is to keep them honest. You know youtube ads are youtube ads.

[@fleachamberlain1905]

I have been interested in permeable pavement for years now, so I really appreciate your explanation of it. You have answered questions I didn't even know to ask. I also noticed, was impressed by and thankful for, you saying "human made".

[@derpionderpson1424]

Got to say I love when a video from you show up in my recommendation, always some awesome info to get.

[@Kaiwala]

Gotta be honest, when answering the questions about this stuff in my construction BTEC I had bumfuck no clue how this stuff worked. Good thing I still passed or else I'd be dusting off the old time machine by now...

[@BusterSwordsman]

A couple things to keep in mind. 1, pervious pavement requires a special street sweeper for road maintenance, one with a strong vacuum. Even then, it does not pick up 100% of the debris in the pores. 2, in the places that it has been installed in my city, the pavement sits on top of roughly 2 feet of drain rock. This means that utilities in the area might have to preemptively go through and lower or reinstall their structures, which could cost 10's of thousands of dollars, depending on the size of the area being replaced. Plus, I would HATE, to have to break that street to fix something like a broken water main.

[@EyeofZai]

while there are additional costs associated with permeable pavement, there are also ways we save significant amounts of money. by utilizing it effectively, we prevent damage from flooding. by ensuring drainage on roads during storms, we can potentially driving safer and prevent accidents. by reducing runoff, we help to prevent phosphorus and nitrogen induced toxic algal blooms that prevent recreation and degrade habitat necessary for commercial fisheries. we can increase the amount of water infiltration into groundwater resources, we prevent often dangerous and costly erosion. in other words, if utilized widely and effectively, and in conjunction with other solutions (regenerative agriculture, more livable cities, etc) it would actually save a lot of money. would it single-handedly solve these problems? no. but it’s a lot better than what we’ve got going on right now.

[@carolinafrog4365]

Reminds me of when, during the construction of the i-85 interchange with i-485 on the west side of Charlotte NC, nice big flat highway that had to be shifted at times to make room for the new ramps and supports. At first the Developers used "hydrophobic" asphalt for its durability, but with the regular rain and cars on these heavy side ways bows in the road(and NC Highway Patrol's painfully lacking ability to... Patrol and enforce speed limits) there were near fatal wrecks daily with cars in the rain exceeding the 55mph work zone speeds and careening over the concrete barriers. NCDOT helped develop a porous asphalt that worked brilliantly to move the water down away from the travel surface, increasing tire grip, but as shown in your presentation, i was no match for the truck traffic(15-30/min), add to that our freezing winter weather, as awesome as the porous pavement was in engineering, it wasnt enough because: Speeds Heavy weight traffic Lack of maintenance Any thoughts on porous pavement incorporating recycled plastics or rubber to dissipate the weight impacts? Perhaps metallic "hairs" to create stronger bonding?

[@izimiger8924]

I dunno how you do it Grady, you're able to convey enthusiasm and professionalism in your videos without being obnoxious or over the top. Stay awsome Sir, and keep up the good work!

[@Timsturbs]

0:24 krymsky bridge near gorky park 3:12 lugniki

[@guymoreau609]

0:36 Chaudière bridge between Ontario and Quebec, Canada during the 2019 spring floods. Overflow from very close hydro dam.

[@solderist]

0:52 With a pink hotel, a boutique, and a swingin' hot spot

[@eugenioluiz9645]

Nice video! I'm graduating in Civil Engineering in Brazil and my conclusion project aims to optimaze pervious concrete - less cement consume with his substituiton and the get around the same strong. I love to see more and more videos about that! However, it's sad how underrated is his application... but I hope that could change in the years

[@charlesviner1565]

Just found your channel and I love it! Like 👍 all your videos and I have subscribed. Thanks. Greetings from Davenport Iowa. Next to and sometimes in the Mississippi River

[@Hypercube9]

"Tell me when you want me to start recording." LOL Your wife's awesome! 😂

[@itsukarine]

having just watched your sinkhole video, im trying to figure out why permeable concrete wouldnt lead to an increase in major issues like sinkholes or lesser issues like potholes (though you did mention it, briefly) would the water not really erode much since it's "trickling" into the ground instead of running like it would from a pipe, and thus removing a lot of its erosive qualities?

[@makeitwork583]

Was that a Lee Valley ‘Peasants Knife’ I saw in the kitchen? Great tool, use it all the time, even gave one to my best friend! Absolutely love your channel! Be well.

[@videogalore]

I don't know if you use them in the US, but here in the UK we use a lot of stormwater 'crates'. It's a modular underground reservoir system to protect against flooding. Some extensions and most new houses have these in some form and they can be a helpful way to manage the volumes needed. It's sometimes tricky to work out the volumes needed however! Congratulations on the Kitchen helper too! As for choosing Vegetarian, it's a great idea to not think of it as a 'hard' line, so if you eat meat then just try to eat less and buy good quality.

[@MrAwesomeSquad]

Shut up everyone, I need to learn about permeable pavement.

[@harveykyle3690]

Lol

[@stefanx8344]

Lol this video is more of a serious education then i ever experienced before.

[@alexanderx33]

You covered several of them but there is one more MAJOR limitation of permeable pavement. It wears really really fast. Even just foot traffic can turn it back into gravel in a visible way in a few months. The problem is that by removing the sand from the concrete mix you remove the vast majority of the contact area between the rock particles resulting in concentration of load on the teeny portland cement bridges. As a result it isn't a long term civil solution, ie not a civil solution, lol.

[@jacktjong1266]

*looks at the entire country of the Netherlands* Here in NL all our public roads are made from permeable asphalt and the road surface is near flawless wherever you go. And this is despite us enduring constant rain and freezing temperatures in the winter.

[@Rampman]

I love watching your videos. I am not an engineer but I learned a lot of engineering stuff, how materials work and many more

[@GMan-yv8cb]

Really enjoy ALL of your videos- including the ones that I THOUGHT I had NO interest in! HERE'S an idea- I visited the city of Spokane, Washington a few years back, and they have QUITE the interesting story that I would LOVE to hear your perspective of !! The range of topics would really be interesting! City drainage, how / why it failed, their work-around solution, how they pulled it off, was it successful?, how did it affect the city- then, now, challenges faced, etc, etc. It was a remarkable engineering feat!

[@soberhippie]

0:24 Hey, that's the Gorky Park in Moscow! Weird how much stock footage is from Russia

[@jimmysgameclips]

Me: 'Not sure how much I'll be into this one- oooh'

[@56independent42]

0:33 Here in Spain, some parking areas are just a bare field. This allows water in whilst also allowing parking. Since you don't drive at speed on the ground, it does not matter if it is just bare. Everything else is dense, villages connected by small roads and towns connected by slightly larger roads.