Concrete With A Drinking Problem Could Reduce Flooding

Concrete – it’s all around you. You probably walk on it, drive on it, and maybe even sit on it! From a civil engineering standpoint, concrete really is a miracle material. But, it does have its downsides, especially in heavily developed urban areas. One of the most glaring of those downsides is the tendency for water to pool and flood on concrete. However, a new concrete formula could dramatically improve that by allowing water to drain quickly through the concrete itself.

While all unsealed concrete technically absorbs water, it does so very inefficiently and quickly becomes saturated. Once that happens, water will pool on the surface. This causes obvious problems for cars, as they become susceptible to hydroplaning. It also creates the potential for flooding in heavily paved areas.

This new concrete formula, called Topmix Permeable, is designed to reduce pooling by letting the water flow through at the rate of 600 liters per minute per square meter! It does this by using larger gravel pieces in the mix, which leaves bigger gaps for the water to drain down into. From there, it can be absorbed by the underlying soil, or routed safely away from roadways and parking lots.

Of course, this formula isn’t perfect. Its ability to pass through water also makes it likely to crack and quickly deteriorate in cold climates, as the water freezing and thawing inside the concrete will easily damage it. But, in warmer climates that receive a lot of rainfall in bursts, it could significantly improve safety.

[via Adafruit]

78 thoughts on “Concrete With A Drinking Problem Could Reduce Flooding

    1. I would expect that depends upon how well the substrate drains (I think the intention is that the water just drains through the top coating) although one wonders how long it lasts given general dirt build-up over time.

    2. In some situations, the freezing cycle is fast enough to defeat this kind of drain. Example, sleet carries a lot of water at near freezing. If the temperature conditions are just right, that water will hit the cold concrete and freeze as it permeats down. Boom, cracks.

      A layer of frost under the concrete is likely going to be slow to thaw during periods of warm days and cold nights (seen during early spring) which will trap the water.

      That’s just two scenarios, I can think of oodles more. All bad.

      Not to mention, what is this going to do to the rebar inside? Iron expands when it turns to rust.

      Then how long is the substrate going to last as well? Last year I had to deal with a road collapse big enough to swallow a truck because the underlying substrate just filtered away.

        1. Yes. Although you see much more used in bridges, rebar(dowel bars) is also used to reinforce the joints between concrete sections. If you ever drive by a freeway construction project, you will see thousands of green coated bars suspended several inches above the ground by wire frames. When you look at the edge of a finished section you can see the short bars sticking out the edge, ready to connect to the next section.

          Although the point is moot, as since normal concrete already absorbs water and salt from the road surface, deterioration of metal reinforcements is already a major problem in existing concrete roadways and bridges.

          As an aside, a search on the topic revealed that my state publishes its research on these topics. Here’s one evaluating newer corrosion resistant bars.
          http://wisdotresearch.wi.gov/wp-content/uploads/wi-03-08dowelbars.pdf

      1. Here in New England our road agents have known about the problems with concrete roadways for decades. The last time I drove on a concrete roadway around here was in the late 1970’s (as a passenger, as I was too young to drive at the time). Even regular concrete doesn’t survive the winters we deal with here, so all of the roads are paved with asphalt, and the newer roads are being built with subsurface drain systems to reduce the damage from frost heaves. This water permeable concrete wouldn’t last through January in this neck of the woods.

  1. I am living in Germany and a 3 km strip of our motorway around my city was renewed with an asphalt which absorbes sounds AND water better. On a rainy day there is no water on it at all. Probably not as good as this product, but it also works in colder climate ;)

    1. You guys are world leaders in flooding defence’s because much of your country is under sea level. Most other places in the world don’t suffer this problem and with all the talk of climate change everyone seems to be looking at Netherlands for idea’s. I live in Scotland so we don’t really have anything to worry about It just keeps raining here but we are high up so we only get localised flooding, But we could use some of that concrete on our roads.

    1. They won’t care. In California, it’s not the fire department’s problem to clean up that kind of mess during or after a fire. That responsibility goes to the tow truck operator. Other states and countries will differ of course.

  2. Maybe with asphalt the ice crystals don’t cause as much fracking. I remember hearing on Purdue radio that they were doing research into quiet surfaces for roads. The porous surface was the quietest. We have bad freeze-thaw conditions here though.

    1. Quiet cars, quiet roads…
      How many people/animals will die because they didn’t hear anything coming?
      Didn’t some automobile manufacturer deliberately allow some sounds to not be muffled on their electric(hybid?) vehicles because they were too quiet?

      1. Electric cars and buses sometimes have noise makers. That said, cars are currently up to 90 dbA. There’s plenty of room for that to come down and still be audible to pedestrians and animals.

        1. Tires do play a major role in travel noise, especially at highway speeds. I recently put new, better quality tires on my car, and even with its fairly loud (by sedan standards) engine noise, it drastically reduced highway road noise overall.

  3. If only the guy who designed the Formula 1 track in South Korea had used this. I watched the first Gran Prix on that track (live on late night TV in the USA) and it was a disaster. The week prior to the race was sunny and dry but on race day it poured down rain.

    The track designer apparently neglected to ask if it rains, ever, in South Korea. The track was completely flat everywhere and had very insufficient drainage. It was so bad that even with rain tires on the race cars the safety cars were lapping the course faster. Aside from the big derp on not designing the track to handle any amount of rain, he put the pit entrance behind a blind corner, making slowing down to enter a dangerous dance with cars coming up behind and not slowing down to go into the pits. At least he put in very large, paved run-off areas on many of the corners. They got used by nearly every driver that day.

    1. That’s funny and a little sad. Everybody has bad days, but it baffles me when a construction project of that magnitude gets bungled that badly. You’d think with those stakes it’d be worth paying somebody to put together a virtual version of the track for test-driving, or something like that. Slap the map into Live for Speed or something. That wouldn’t solve the drainage, but it’d at least find the usability concerns.

      1. The new hospital in the town where I grew up (if I ever REALLY grew up B^) had overhead doors for the ER two small for modern ambulances! IIRC, also the doors to the patient rooms were too narrow to allow a gurney to pass through as well!

    2. I live in South Korea, and this is typical of the general lack of joined-up thinking displayed here. It pervades all aspects of life here.

      You may have read that South Korea has the fastest internet in the world. Well, it’s true. It’s everywhere, even fibre in tiny rural towns, and it’s cheap. But they run Windows everywhere with bloated activeX objects, flash, and blocks of text rendered as jpegs. This chokes up the network with massive overheads so the general public gets a ‘normal’ (i.e. not fast) internet.

      So, the Grand Prix track screwup is just another manifestation of South Korean incompetence. Don’t believe the hype.

      Oh, and it does rain here occasionally. :)

    3. How about the Japan F1 track? You know, where one corner last year resulted in an accident in two consecutive laps, with the second accident being fatal; just because it started raining heavily rather suddenly?

      That said, I haven’t seen the South Korea track. I don’t get all of the Grand Prix races, FIA F1 just barely shows up on Comcast Sports Network. And F1 dropped the Korea track this year because of all of those issues.

  4. Here in the UK, we don’t generally use concrete for roads or car parks, due to how easily it cracks with the regular freeze/thaw cycles we have here. Instead we have tarmac – a mixture of gravel and tar. That’s what this product is, not concrete.

    1. It certainly looks like tarmac but the safety data sheet says it is a readymix cement concrete with a colouring agent. Also it is no good for high speeds and heavy breaking – so it is really for car parks.

      1. LaFarge makes a huge range of cement and asphalt products, and will customise them for the job. If you see any video of the running track in Glasgow used for the Commonwealth games, that was a self draining asphalt top like this with a permeable subsurface. I’ve seen a variant of this in use in car parks with permeable on the parking areas and impermeable on the driving lanes. The surface geometry was such that they didn’t need the traditional sort of drainage.

    2. In the uk concrete is used for concrete wear pads for its improved ability to resist abrasion over tarmac, its not used defacto because its more expensive than regular asphalt , a sod to repair and noisier for the traffic passing over it but in braking zones on motorways, near exit ramps etc, you will notice pads of concrete to cope with the wear. Lots of other places use it for its differing mechanical properties also, station forecourts because its more resistant to fuel spillage, bus stops etc.
      Cracking is dealt with by having the pad off level, its called “superelevation” in technical terms and uk motorways and roads are designed with a crown which falls away to the gutters on the edge.
      What is pretty noticeable to me is that when I drive in france, the super elevation is much lower on the autoroutes, and they tend to pool in wet weather, making driving more dangerous. Not sure why this but probably connected to cost of construction is but its a definite effect.

  5. I live in northern Germany. Here are at least two highways with a similar type of concrete. Most talked about problems occur in summer during hot periods not in winter. The used type of concrete throws large (30cm) bubbles due to encapsulated water evaporating. I’m no road expert, but to me it seams it behaves as good as normal concrete in cold conditions, which also has its problems with ice.

    1. Moin! I also live in northern Germany. And it barely snows here. But the water quantity we get here (from raining) is huge (being close to the north sea) but I have NEVER seen a road that had water on it, or for that matter, any accidents caused by water buildup on roads/highways. Also the days that it really is summer are very limited, at almost two weeks of hot days per year. So the temperatures are mostly constant during the year, ranging from -2 to 10 degrees C in the winter, and from 15 to 25 in the summer.

    1. My thoughts exactly. The water isn’t disappearing into thin air – it’s just under the concrete now. Unless there’s some pretty hefty drainage systems (the same type needed to keep a normal concrete parking lot from flooding) it’s just going to build up underneath, and cause sinkholes.

    1. Obviously you have a more traditional substrate that doesn’t erode away like bare earth. This kind of thing is usually installed as a top layer over traditional, non-permeable concrete.

  6. If you know the term “pervious concrete”, then you know it’s been in use for decades, and you recognize that this is nothing more than a PR coup for the Topmix company. A well-executed one, to be sure, but I’m sorry to say you fell for it, HAD.

    1. You’re exactly right! This stuff is pretty old hat. Most people just don’t use it unless forced by local environmental regulations (runoff mitigation) because it is decidedly less durable.

  7. All the parking lots at my church are done with permeable asphalt. It’s neat but it isn’t as durable as standard asphalt, so the main entry driveway and traffic paths had to be done with standard stuff. We did a dump test like this video and the results are way more impressive to see in person than this video even shows. There are still standard drains in the lot as well in case of a particularly prodigious rainfall or degradation of the system over time.

    I’ll be interested to see how it holds up over time, and how quickly it clogs up due to small dirt particles washing into the cracks and plugging it.

  8. Permeable paving is used extensively in the Pacific Northwest as part of the stormwater system. Permeable concrete and asphalt is used mainly in parking areas and not main traffic lanes as it is not as durable as regular paving. It is the visible part of the stormwater system that collects the stormwater, stores it, infiltrates some of it into the ground, and treats it through biological action. Systems such as this decreases the runoff, spreads the duration of the runoff over a longer period of time, and treats the runoff to remove the oils that cars leaks. An extensive underground drainage system is placed below the paving consisting of thick layer (9 to 12 inches) of gravel. This system does require maintenance as it dirt clogs it up.

  9. Why are so many people commenting on how poorly this will work in cold climates? The article CLEARLY states it is not recommended for cold climates! The office of redundant redundancy needs to be called it seems ….

  10. The concrete foundation of my 100-year-old house was made with something similar (I call it “rubblecrete”). So, my basement always flooded and the walls were falling apart. I replaced it.

  11. where using sumting simulair to that in the netherlands
    its called open asphalt concrete
    it allso reduces noize from tires and engine giving more comfort to the people living near these roads
    downsides salt doesnt work on the stuff when it snows they need to use some sort of anti freese gell
    longer distance traveled when emergency braking either wet or dry
    and yes it does crack when frozen and thawing leaving potholes
    it basicly crumbles so you need to realy prevent it from freesing up in te first place
    over time the open structure fills with sand and dirt so it requires more regular replacement to keep it working

  12. Think about this – water reclamation in urban areas. There could be a sheet underneath the concrete that drains into a water recollection system. The water could be filtered and used for urban horticulture!

  13. Bit of a problem that due to climate change we can’t really tell where it’s going to freeze next.
    Not so long ago (last year) I saw snow on TV weather reports in places where there isn’t suppose to be snow.

  14. What I see when looking at the daily mail graphic of comparing all 3 systems. I see is the topmix sitting atop what is essentially one big ass flat box culvert that will fill up flooding the surface of the pavement. That box culvert is going to have to empty to ground surface at some point, still creating down stream flooding problems. Even if the box culvert is made deep enought to hold a season’s worth of precipitation, and depending on evaporation to help drain it out, tit’s goinf to be pretty big mosquito nursery. No doubt it has it’s application, but universal application probably not.

  15. Freezing isn’t a problem because high rainfall isn’t a problem where it freezes. You may think you’ve seen heavy rain, but you have not. I was driving at night once in my old hometown of Cairns (tropical north Queensland, Australia) during a monsoon storm. The rain suddenly thickened until there was about 1 meter of visibility. No fog, no mist, just rain. I slowed to 5km/h, but then I heard a crunch sound, got out and found myself on a roundabout. From inside the car I couldn’t even see a kerb directly in front of me.

    The point of this road surface is not to make it safer where it constantly rains, but to make it safer where the entire annual rainfall occurs in 6 hours.

    1. Here in Maryland usa we have hurricane rains worse than that and random times where it drops below freezing in the early spring and late fall that can follow heavy rains … This would be a big problem

  16. As Tom said above: we have this stuff in The Netherlands.

    When it rains, you get much less spray from the cars in front of you. It’s safer that way. When it rains, the surface often remains mostly dry. The lack of a layer of water on the tarmac means you get better braking action. It is safer than normal tarmac that way.

    The downside is that it doesn’t last as long as the normal stuff. Quite strongly because of the freezing in winter. And, as I understand things, it requires a minimum amount of cars passing to remain permeable. It clogs up if there are less than the minimum amount of cars.

  17. I am really baffled as to why this is suddenly a “new” concept when it has clearly been around for ages in one form or another. While I understand that this is a different mix design, pervious concrete if cleaned and operating normally and designed with the proper mindset can withstand freeze-thaw cycles.
    http://www.nrmca.org/aboutconcrete/pervious%20concrete%20-%20-%20freeze-thaw%20durability%20per%20nrmca.pdf

  18. Even if this doesn’t work for roads, it could still have applications in drainage.

    Where traditional edging drains fill with leaves, this could act as a filter layer and provide a more aesthetically pleasing solution. The silt that makes it through should be easy enough to flush as part of routine maintenance.

  19. interestingly you can buy pavers that are made like this, but with epoxy and more attractive stones, however they’re cost prohibitive. like thirty bucks a square foot i think. maybe they were 14″x14″ but still, too spendy unless it’s next to a pond or something, with adequate drainage underneath.

  20. and I see some other problems there too:
    If you dont put an apropriate foundation under that stuff, the water will likely wash big “bubles” into the soil underneath it,
    so happy “oh there is another pothole”-day ;)

    And if you do the drainage stuff you`ld need to prevent that, you could also put an apropriate drainage system directly into the surface like the one which worked quite well the last decades…

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