Permeable concrete is interesting
September 29, 2015 5:00 PM Subscribe
(Product video) Topmix Permeable has a claimed average permeability rate of 600 litres, per minute, per square meter. Watch the concrete in a small area of car park soak up 4,000 litres in a minute. An explanation version and a few caveats.
In the same car park, another test, and one at the UNH Stormwater Center. For variety, here's a driveway and here's some porous asphalt.
In the same car park, another test, and one at the UNH Stormwater Center. For variety, here's a driveway and here's some porous asphalt.
They should rebuild New Orleans with this stuff.
posted by valkane at 5:08 PM on September 29, 2015 [5 favorites]
posted by valkane at 5:08 PM on September 29, 2015 [5 favorites]
According to the citylab link it also can't handle "intense traffic" or "heavy vehicle loads." But they mentioned using it for sidewalks which seems like a genius application. Now we just have to get politicians interested in repairing and rebuilding infrastructure.
posted by Neronomius at 5:17 PM on September 29, 2015 [3 favorites]
posted by Neronomius at 5:17 PM on September 29, 2015 [3 favorites]
Watching them lay the driveway without rebar (second to the last link) just seemed odd...
posted by fremen at 5:22 PM on September 29, 2015
posted by fremen at 5:22 PM on September 29, 2015
(probably not intended, but the explanation version has a t= in the URL, causing the player to skip past most of the explanation.)
posted by effbot at 5:23 PM on September 29, 2015
posted by effbot at 5:23 PM on September 29, 2015
1. Doesn't work in freezing areas.
I wondered about that, but '...Lafarge Tarmac says its product has “excellent freeze-thaw resistance.”'
Last year, Milwaukee did at least one "test street" with a more permeable concrete.
posted by drezdn at 5:25 PM on September 29, 2015
I wondered about that, but '...Lafarge Tarmac says its product has “excellent freeze-thaw resistance.”'
Last year, Milwaukee did at least one "test street" with a more permeable concrete.
posted by drezdn at 5:25 PM on September 29, 2015
Some of this was installed around the corner from my house in a stretch of formally traditional concrete sidewalk that was apparently slowly killing several 50+ year old street trees by constricting their roots (it is also more flexible than concrete). I talked to the contractors, and they said the city would be using it selectively because of the expense, but that they had a number of pending jobs connected to a DC plan to reduce impermeable surfaces and the number of times each year that our antiquated storm sewer system is overwhelmed. It's raining here tonight, and it really does suck up the water.
posted by ryanshepard at 5:29 PM on September 29, 2015 [11 favorites]
posted by ryanshepard at 5:29 PM on September 29, 2015 [11 favorites]
The sidewalk in front of my house turns into a river every time it rains hard. It would be nice to have the water just flow through the sidewalk and drain away.
The thing is, if the sidewalk was that permeable, where would that water go once it flowed through into the ground underneath? The soil around here is pure clay. If the water can't soak into the ground under the sidewalk, where will it go once it flows through? I suppose that if the right kind of roadbed was installed underneath it could work, but that's an awful lot of sand that would need to be trucked in.
What's under the parking lot in that video? A storm drain?
posted by elizilla at 5:38 PM on September 29, 2015 [5 favorites]
The thing is, if the sidewalk was that permeable, where would that water go once it flowed through into the ground underneath? The soil around here is pure clay. If the water can't soak into the ground under the sidewalk, where will it go once it flows through? I suppose that if the right kind of roadbed was installed underneath it could work, but that's an awful lot of sand that would need to be trucked in.
What's under the parking lot in that video? A storm drain?
posted by elizilla at 5:38 PM on September 29, 2015 [5 favorites]
absalom: It's super neat stuff, but somewhat impractical for real civil projects because .....
1. Doesn't work in freezing areas.
absalom, you're gonna want to sit down for this shocker:
Sometimes they build civil projects in places that don't freeze.
posted by IAmBroom at 5:40 PM on September 29, 2015 [19 favorites]
1. Doesn't work in freezing areas.
absalom, you're gonna want to sit down for this shocker:
Sometimes they build civil projects in places that don't freeze.
posted by IAmBroom at 5:40 PM on September 29, 2015 [19 favorites]
Watching them lay the driveway without rebar (second to the last link) just seemed odd...
Why on earth would you lay rebar in a driveway? It's only going to be a 100mm thick slab. You put 12mm rebar in there you're not going to have a hell of a lot of concrete at the joins.
posted by Talez at 5:44 PM on September 29, 2015
Why on earth would you lay rebar in a driveway? It's only going to be a 100mm thick slab. You put 12mm rebar in there you're not going to have a hell of a lot of concrete at the joins.
posted by Talez at 5:44 PM on September 29, 2015
Watching them lay the driveway without rebar (second to the last link) just seemed odd...
Well, any rebar would effectively be exposed to the elements, wouldn't it?
posted by ChurchHatesTucker at 5:44 PM on September 29, 2015 [1 favorite]
Well, any rebar would effectively be exposed to the elements, wouldn't it?
posted by ChurchHatesTucker at 5:44 PM on September 29, 2015 [1 favorite]
elizilla: water can't soak into the ground under the sidewalk, where will it go once it flows through? I suppose that if the right kind of roadbed was installed underneath it could work, but that's an awful lot of sand that would need to be trucked in.
What's under the parking lot in that video? A storm drain?
It requires a high-drainage substrate, which is part of the entire design package.
It really won't work for New Orleans, I'm betting, because the water won't leave the area after permeating the asphalt, and so the water level would quickly build up to saturation. Hard-top runoff to sewers is probably a better plan for moving excess water in lowland areas.
But I'm just guessing. My point is that this moves water from above the road to just below it very quickly, but since the substrate won't let that water move as quickly as if it were all on top, it's actually making the problem worse.
Areas with good runoff capacity (ditches near the roadway, or inclines in the road) would benefit much more.
posted by IAmBroom at 5:45 PM on September 29, 2015 [1 favorite]
What's under the parking lot in that video? A storm drain?
It requires a high-drainage substrate, which is part of the entire design package.
It really won't work for New Orleans, I'm betting, because the water won't leave the area after permeating the asphalt, and so the water level would quickly build up to saturation. Hard-top runoff to sewers is probably a better plan for moving excess water in lowland areas.
But I'm just guessing. My point is that this moves water from above the road to just below it very quickly, but since the substrate won't let that water move as quickly as if it were all on top, it's actually making the problem worse.
Areas with good runoff capacity (ditches near the roadway, or inclines in the road) would benefit much more.
posted by IAmBroom at 5:45 PM on September 29, 2015 [1 favorite]
Sometimes they build civil projects in places that don't freeze.
You'd be surprised where it freezes. NOLA was mentioned upthread. Last year we had two ice storms which shut down the entire city because every single bridge and a lot of ground-contact paved surfaces were frozen over with as much as an inch of ice. I had to spend two nights in hotels because I couldn't get home. It stayed below freezing for over 48 hours during the second storm, and the general manager of the Lake Pontchartrain Causeway was almost literally in tears; they could not get to the middle third of the bridge at all to inspect it because neither of the high humps at the 1/3 intervals were passable even with 4WD.
posted by Bringer Tom at 5:45 PM on September 29, 2015 [8 favorites]
You'd be surprised where it freezes. NOLA was mentioned upthread. Last year we had two ice storms which shut down the entire city because every single bridge and a lot of ground-contact paved surfaces were frozen over with as much as an inch of ice. I had to spend two nights in hotels because I couldn't get home. It stayed below freezing for over 48 hours during the second storm, and the general manager of the Lake Pontchartrain Causeway was almost literally in tears; they could not get to the middle third of the bridge at all to inspect it because neither of the high humps at the 1/3 intervals were passable even with 4WD.
posted by Bringer Tom at 5:45 PM on September 29, 2015 [8 favorites]
It's hypnotic watching them pour water on that stuff. Violates your intuitive expectations about how water and concrete work.
posted by gusandrews at 5:46 PM on September 29, 2015 [11 favorites]
posted by gusandrews at 5:46 PM on September 29, 2015 [11 favorites]
...its ability to absorb water can be compromised by dirt and other particulate waste, such as sawdust or silt.
Waiting in line at City Hall last week, I overheard two contractors discussing an installation in my area. One mentioned the particulate clogging up the concrete, and that the installation site has scheduled service to "vacuum" the concrete as a kind of reverse pressure washing.
posted by ElGuapo at 5:49 PM on September 29, 2015 [3 favorites]
Waiting in line at City Hall last week, I overheard two contractors discussing an installation in my area. One mentioned the particulate clogging up the concrete, and that the installation site has scheduled service to "vacuum" the concrete as a kind of reverse pressure washing.
posted by ElGuapo at 5:49 PM on September 29, 2015 [3 favorites]
It stayed below freezing for over 48 hours during the second storm, and the general manager of the Lake Pontchartrain Causeway was almost literally in tears; they could not get to the middle third of the bridge at all to inspect it because neither of the high humps at the 1/3 intervals were passable even with 4WD.
I actually had to read this twice, and then think about it. The Lake Ponchartrain causeway is at a mean latitude of 30.1997 N.
posted by cromagnon at 5:56 PM on September 29, 2015
I actually had to read this twice, and then think about it. The Lake Ponchartrain causeway is at a mean latitude of 30.1997 N.
posted by cromagnon at 5:56 PM on September 29, 2015
Oh my god that video. Now I'm wondering if that stuff could've mitigated the flooding here on Long Island from Hurricane Sandy. The thing that causes flooding isn't excessive rainfall, it's storm surge.
I'm also wondering whether this creates a long-term problem with erosion of soil around the paved areas? It seems like it intuitively would, but it does not behave like an intuitive material.
posted by Andrhia at 5:58 PM on September 29, 2015
I'm also wondering whether this creates a long-term problem with erosion of soil around the paved areas? It seems like it intuitively would, but it does not behave like an intuitive material.
posted by Andrhia at 5:58 PM on September 29, 2015
Why on earth would you lay rebar in a driveway? It's only going to be a 100mm thick slab. You put 12mm rebar in there you're not going to have a hell of a lot of concrete at the joins.
Rebar in this stuff would be a disaster. It'd rust out, rust expands, and that'll shatter the concrete. That's a big enough problem in the snow belt as is, with impervious concrete cracking and letting water in, with this stuff, which explicitly does so, I suspect rebar would seriously reduce the lifetime of the slab.
posted by eriko at 6:08 PM on September 29, 2015 [1 favorite]
Rebar in this stuff would be a disaster. It'd rust out, rust expands, and that'll shatter the concrete. That's a big enough problem in the snow belt as is, with impervious concrete cracking and letting water in, with this stuff, which explicitly does so, I suspect rebar would seriously reduce the lifetime of the slab.
posted by eriko at 6:08 PM on September 29, 2015 [1 favorite]
Last year we had two ice storms which shut down the entire city because every single bridge and a lot of ground-contact paved surfaces were frozen over with as much as an inch of ice.
That's not the sort of freezing that destroys concrete, though. What happens in places with real freezing is that water gets under the road, into the road bed (via cracks or potholes or whatever) and then as the ground freezes, it heaves up.
It's worse if there is a diurnal freeze thaw cycle - and roads are great for that, because they heat up in sunlight and cool off at night.
Permeable concrete would be particularly susceptible to this, especially in places where drainage was poor or had otherwise failed.
posted by Pogo_Fuzzybutt at 6:12 PM on September 29, 2015 [1 favorite]
That's not the sort of freezing that destroys concrete, though. What happens in places with real freezing is that water gets under the road, into the road bed (via cracks or potholes or whatever) and then as the ground freezes, it heaves up.
It's worse if there is a diurnal freeze thaw cycle - and roads are great for that, because they heat up in sunlight and cool off at night.
Permeable concrete would be particularly susceptible to this, especially in places where drainage was poor or had otherwise failed.
posted by Pogo_Fuzzybutt at 6:12 PM on September 29, 2015 [1 favorite]
This, or a similar material, was used for a new parking lot at work a few years ago. I was reminded of this recently when I spilled a bunch of water and it disappeared rather than ran off. This is in New York and it works just fine below freezing, though the lot does need to be vacuumed every so often.
posted by plastic_animals at 6:15 PM on September 29, 2015 [1 favorite]
posted by plastic_animals at 6:15 PM on September 29, 2015 [1 favorite]
Seems like that much water flowing through would make it much more difficult to build a roadbed that would not erode. Erosion of the base is the main cause of potholes, after all.
That said, the vast majority of the impermeable surfaces in suburban areas are the vast parking lots, not the roads themselves, so I can definitely see a good use for this stuff there.
If the base erosion can be controlled, I definitely wouldn't mind seeing some of this stuff in South Florida. Most of the highways are built with better drainage than is found in most of the country, but the tropical rains come down hard enough that an excessive amount of water remains on top of the road surface. Not standing water, mind you, water that is actually flowing into the drainage system. It just can't flow quickly enough at any reasonable grade.
posted by wierdo at 6:19 PM on September 29, 2015 [1 favorite]
That said, the vast majority of the impermeable surfaces in suburban areas are the vast parking lots, not the roads themselves, so I can definitely see a good use for this stuff there.
If the base erosion can be controlled, I definitely wouldn't mind seeing some of this stuff in South Florida. Most of the highways are built with better drainage than is found in most of the country, but the tropical rains come down hard enough that an excessive amount of water remains on top of the road surface. Not standing water, mind you, water that is actually flowing into the drainage system. It just can't flow quickly enough at any reasonable grade.
posted by wierdo at 6:19 PM on September 29, 2015 [1 favorite]
I actually had to read this twice, and then think about it. The Lake Ponchartrain causeway is at a mean latitude of 30.1997 N.
That meandering polar jet stream is a bitch.
posted by Talez at 6:38 PM on September 29, 2015 [3 favorites]
That meandering polar jet stream is a bitch.
posted by Talez at 6:38 PM on September 29, 2015 [3 favorites]
They've been using a couple versions of the permeable concrete around me ... in parking lots and on small residential streets, usually older streets in neighborhoods that date prior to 1900 that are about a lane and a half wide, often without sidewalks and usually with lawns. (Because they need repaving and there are grants for older neighborhoods upgrading roads while experimenting with newer paving technology.) I haven't seen any notable winter heaving yet on the experimental projects, which have been slowly expanding. The VAST MAJORITY of urban streets here in Peoria are quiet urban streets that only handle local resident traffic and a few FedEx trucks. Peoria's under an EPA storm sewer remediation order, and "From a single rainstorm, Peoria needs to be able to capture about 60 Olympic-sized swimming pools of water, or about 37 million gallons." "The city’s strategy is to narrow streets within an 8 square mile section of the city that contains some of its oldest streets and sewers. Approximately one-third of streets within that section would be redesigned with permeable pavers and native plants or trees integrated into the landscaping on public property."
So a pretty small amount of permeable paving -- 1/3 of 8 square miles -- combined with rain gardening should basically eliminate one of the worst combined sewer overflow problems in the country. Even if it only does half of that, it seems like a pretty good deal.
posted by Eyebrows McGee at 6:39 PM on September 29, 2015 [2 favorites]
So a pretty small amount of permeable paving -- 1/3 of 8 square miles -- combined with rain gardening should basically eliminate one of the worst combined sewer overflow problems in the country. Even if it only does half of that, it seems like a pretty good deal.
posted by Eyebrows McGee at 6:39 PM on September 29, 2015 [2 favorites]
Applying this to all the places it makes sense would solve a huge ecological problem with flooding and runoff from urban developments.
posted by Annika Cicada at 6:59 PM on September 29, 2015
posted by Annika Cicada at 6:59 PM on September 29, 2015
Do they have to use a biocide to keep algae from colonizing it?
And considering the effects of light, I wonder whether you could put some TiO2 in the top 1/4" to make it 'burn' some of the oil and other hydrocarbons that get deposited on it before they can soak into the ground and pollute the water table -- and maybe even deal with algae.
posted by jamjam at 7:08 PM on September 29, 2015 [1 favorite]
And considering the effects of light, I wonder whether you could put some TiO2 in the top 1/4" to make it 'burn' some of the oil and other hydrocarbons that get deposited on it before they can soak into the ground and pollute the water table -- and maybe even deal with algae.
posted by jamjam at 7:08 PM on September 29, 2015 [1 favorite]
regardless of caveats both explicit and speculative, this is a pretty incredible achievement. Stuff like this didn't used to exist. Now it does, and it looks useful. Something new under the sun.
posted by Anticipation Of A New Lover's Arrival, The at 7:40 PM on September 29, 2015 [7 favorites]
posted by Anticipation Of A New Lover's Arrival, The at 7:40 PM on September 29, 2015 [7 favorites]
My guess is that dirt and dust would be the biggest problem; I bet it would be totally clogged within a season if it wasn't constantly vacuumed (as plastic_animals mentioned upthread).
posted by Greg_Ace at 7:43 PM on September 29, 2015
posted by Greg_Ace at 7:43 PM on September 29, 2015
I think I first read about this in testing in Europe about fifteen years ago, maybe a bit more recently. I'm glad to hear that it is starting to get used more in the US. There are a lot of unnecessary impervious surfaces that could be replaced with a variety of permeable surfaces; this has the huge advantage of being both permeable and ADA compliant, so ideal for parking lots and other high-use areas.
posted by Dip Flash at 7:51 PM on September 29, 2015 [1 favorite]
posted by Dip Flash at 7:51 PM on September 29, 2015 [1 favorite]
Someone should combine this with LitraCon to make water-permeable, translucent city streets. We can grow gardens under them!
posted by oulipian at 7:55 PM on September 29, 2015 [1 favorite]
posted by oulipian at 7:55 PM on September 29, 2015 [1 favorite]
It's too bad that this stuff isn't good for cold climates, we could use something like that here. It's been pouring rain here all day which means that all that rainwater will flow to the sewage plant which will get overloaded and have to dump raw sewage into the Ohio once again. We're supposed to get separate storm and septic systems some day but that won't be for decades at the rate things move here. More permeable surfaces would make for a great stop-gap strategy until the sewer system is finally modernized.
posted by octothorpe at 7:57 PM on September 29, 2015
posted by octothorpe at 7:57 PM on September 29, 2015
Sometimes they build civil projects in places that don't freeze.
I agree, and the states that could most benefit from it are the ones most averse to the taxes it would take pay for the stuff. I was just lamenting that fact.
posted by absalom at 8:20 PM on September 29, 2015
I agree, and the states that could most benefit from it are the ones most averse to the taxes it would take pay for the stuff. I was just lamenting that fact.
posted by absalom at 8:20 PM on September 29, 2015
"I bet it would be totally clogged within a season if it wasn't constantly vacuumed"
AFAIK they clean the similar surfaces here with the regular street sweeper twice a year on the same schedule as the rest of the city but I will see if I can ask a friend in the city manager's office if they do anything special to maintain it.
posted by Eyebrows McGee at 8:24 PM on September 29, 2015 [1 favorite]
AFAIK they clean the similar surfaces here with the regular street sweeper twice a year on the same schedule as the rest of the city but I will see if I can ask a friend in the city manager's office if they do anything special to maintain it.
posted by Eyebrows McGee at 8:24 PM on September 29, 2015 [1 favorite]
Applying this to all the places it makes sense would solve a huge ecological problem with flooding and runoff from urban developments.
And that's basically the entire intent. You route runoff from the actual hard, solid driving surfaces of your project towards areas of permeable concrete (I've generally just seen it used for small car parking areas, not drive aisles), and that keeps chemicals and oil that aggregates on the parking lot from getting into the storm drains and then flowing out to whatever body of water your municipality routes its stormwater toward. Not to mention fertilizer or pesticide runoff from landscape areas. You used to be able to get a LEED point for having permeable surfaces for a certain percentage of your parking areas, which is kind of how this stuff came about. I saw similar stuff demonstrated 10 years ago in California.
posted by LionIndex at 8:27 PM on September 29, 2015 [1 favorite]
And that's basically the entire intent. You route runoff from the actual hard, solid driving surfaces of your project towards areas of permeable concrete (I've generally just seen it used for small car parking areas, not drive aisles), and that keeps chemicals and oil that aggregates on the parking lot from getting into the storm drains and then flowing out to whatever body of water your municipality routes its stormwater toward. Not to mention fertilizer or pesticide runoff from landscape areas. You used to be able to get a LEED point for having permeable surfaces for a certain percentage of your parking areas, which is kind of how this stuff came about. I saw similar stuff demonstrated 10 years ago in California.
posted by LionIndex at 8:27 PM on September 29, 2015 [1 favorite]
We use this stuff where I work. More the asphalt, for various reasons I don't remember. This is in Philadelphia, so it very much does freeze here. It's an ongoing experiment to determine the best assembly, and there are some things it's not suited to. The water department here is very focused on meeting EPA requirements through managing run-off with strategies like this, so it's becoming a lot more common.
In the early stages of the projects I generally work on, the civil engineer will determine what the stormwater mitigation requirements are for the site and come up with a strategy. If soaking into the ground is part of the strategy, they'll do a perc[olation] test to see how quickly the ground on site will absorb water, and size the area accordingly. If it doesn't absorb quickly enough, we can dig out an area and fill it with stone to act as a large dry well.
Anyway, so then the porous asphalt may go on top of that, with the amount and type of stone under it determined by how much weight you want to drive over it. It doesn't hold up to weight well, which can be a problem if you want to use a bucket truck to change the light bulbs at your porous asphalt basketball court. If you can work that out, though, it's great on courts because they become playable very quickly after rain. For parking lots they usually put it only in the parking spaces. It's been tried on a street or two here, but these were tiny streets no wider than a single car if I remember correctly. Getting the binder right can be a problem and we had a couple of installations that were far too mushy and had to be redone. Others have held up well for years now, and I think it's becoming a little less unusual an order at the couple of asphalt plants that make it, so it's more consistent. I think there's now a standard Superpave mix for the asphalt.
You are supposed to vacuum it. I don't know how often this actually happens. It's fine in the cold, but you're supposed to only use brine to salt it, not straight salt, which also probably doesn't happen very often. It's tricky to plow, too.
Short version - it has some constraints but is in pretty regular and successful use now.
posted by sepviva at 8:54 PM on September 29, 2015 [11 favorites]
In the early stages of the projects I generally work on, the civil engineer will determine what the stormwater mitigation requirements are for the site and come up with a strategy. If soaking into the ground is part of the strategy, they'll do a perc[olation] test to see how quickly the ground on site will absorb water, and size the area accordingly. If it doesn't absorb quickly enough, we can dig out an area and fill it with stone to act as a large dry well.
Anyway, so then the porous asphalt may go on top of that, with the amount and type of stone under it determined by how much weight you want to drive over it. It doesn't hold up to weight well, which can be a problem if you want to use a bucket truck to change the light bulbs at your porous asphalt basketball court. If you can work that out, though, it's great on courts because they become playable very quickly after rain. For parking lots they usually put it only in the parking spaces. It's been tried on a street or two here, but these were tiny streets no wider than a single car if I remember correctly. Getting the binder right can be a problem and we had a couple of installations that were far too mushy and had to be redone. Others have held up well for years now, and I think it's becoming a little less unusual an order at the couple of asphalt plants that make it, so it's more consistent. I think there's now a standard Superpave mix for the asphalt.
You are supposed to vacuum it. I don't know how often this actually happens. It's fine in the cold, but you're supposed to only use brine to salt it, not straight salt, which also probably doesn't happen very often. It's tricky to plow, too.
Short version - it has some constraints but is in pretty regular and successful use now.
posted by sepviva at 8:54 PM on September 29, 2015 [11 favorites]
This might be good in Los Angeles, where rain is rushed out to sea, not allowed to fill wells and aquifers underground because of surface structures.
posted by Brian B. at 10:43 PM on September 29, 2015 [1 favorite]
posted by Brian B. at 10:43 PM on September 29, 2015 [1 favorite]
When I saw this, I freaked out, because now we are pulling drinking water from our groundwater in California. Install here first please, we never freeze!
posted by yueliang at 12:14 AM on September 30, 2015
posted by yueliang at 12:14 AM on September 30, 2015
where would that water go once it flowed through into the ground underneath? The soil around here is pure clay.
Valid point, urban soils can get compacted denser than concrete. It sounds like this tech would work really well on top of engineered soil mixes for street trees and such
posted by BinGregory at 1:20 AM on September 30, 2015
Valid point, urban soils can get compacted denser than concrete. It sounds like this tech would work really well on top of engineered soil mixes for street trees and such
posted by BinGregory at 1:20 AM on September 30, 2015
Some discussion of structural/engineered soils for stormwater management and tree health, from American Society of Landscape Architects (pdf).
posted by BinGregory at 1:27 AM on September 30, 2015
posted by BinGregory at 1:27 AM on September 30, 2015
At least one of the freeways where I live was paved with permeable asphalt (280 in the Bay Area). It's pretty great for visibility when it's raining because the cars don't throw up any spray.
posted by ryanrs at 2:42 AM on September 30, 2015
posted by ryanrs at 2:42 AM on September 30, 2015
You don't have to make the entire area use this stuff. A grid of permeable surface could be used for storm drains that won't clog, or raised-table cycle paths, or other features. This could be an increase to drainage surface without necessarily needing to take over all the motorways.
I'd be interested in a breakdown of the sources of the increased cost. If it's all known materials that cause it, such as the aggregate, then it's not likely to improve. But if it's tools and methods, then that's the kind of thing we're good at driving down over time.
posted by rum-soaked space hobo at 3:45 AM on September 30, 2015 [3 favorites]
I'd be interested in a breakdown of the sources of the increased cost. If it's all known materials that cause it, such as the aggregate, then it's not likely to improve. But if it's tools and methods, then that's the kind of thing we're good at driving down over time.
posted by rum-soaked space hobo at 3:45 AM on September 30, 2015 [3 favorites]
sepviva: in the explanation video, it says that the advance here is that they've finally worked out a formula that can withstand the weight of vehicles (hence the cement mixer pouring water on the demo car park)
posted by rum-soaked space hobo at 4:13 AM on September 30, 2015
posted by rum-soaked space hobo at 4:13 AM on September 30, 2015
One thing that really confuses me is that I just realised that USAmericans use asphalt and concrete as synonyms. Wait a minute, they're not. Concrete is a mixture of cement, sand and aggregates, asphalt is a mixture of heavy hydrocarbons (pitch) and aggregates. Quite different products in Australian English.
posted by wilful at 4:30 AM on September 30, 2015
posted by wilful at 4:30 AM on September 30, 2015
Asphalt and concrete are very different things, they're in no way synonyms.
posted by octothorpe at 4:49 AM on September 30, 2015
posted by octothorpe at 4:49 AM on September 30, 2015
Asphalt and concrete are very different things, they're in no way synonyms.
Indeed. But the second video uses the terms interchangeably.
posted by wilful at 4:54 AM on September 30, 2015
Indeed. But the second video uses the terms interchangeably.
posted by wilful at 4:54 AM on September 30, 2015
Americans don't synonymize asphalt and concrete, that I've ever noticed. I suppose some people here might do that, but if I heard it I would interpret it as confusing and/or incorrect. Asphalt is the black stuff, concrete is the gray stuff.
Sometimes people call asphalt "tar" instead, which isn't strictly correct but which works in the right context. Also a lot of folks seem unclear on the difference between concrete and cement and will use the two terms interchangeably. Nobody uses concrete and asphalt interchangeably though, or at least it's not generally accepted usage.
posted by Anticipation Of A New Lover's Arrival, The at 4:58 AM on September 30, 2015
Sometimes people call asphalt "tar" instead, which isn't strictly correct but which works in the right context. Also a lot of folks seem unclear on the difference between concrete and cement and will use the two terms interchangeably. Nobody uses concrete and asphalt interchangeably though, or at least it's not generally accepted usage.
posted by Anticipation Of A New Lover's Arrival, The at 4:58 AM on September 30, 2015
We don't use them as synonyms, usually. When you get technical though, asphalt is a binder in the type of concrete we call "asphalt." So ¯\_(ツ)_/¯
posted by zennie at 5:00 AM on September 30, 2015 [1 favorite]
posted by zennie at 5:00 AM on September 30, 2015 [1 favorite]
OK, I accept it's not USAmericans, it's the dumb video producer. It's not important. Glad we cleared that up.
In the inner urban areas of Melbourne, a pebble mix with resin coating is used around the base of the large street trees, so that water can infiltrate but it's not dusty or muddy. Always thought that was clever engineering, to get just the right mix to keep the spaces for water while still keeping structure.
posted by wilful at 5:02 AM on September 30, 2015
In the inner urban areas of Melbourne, a pebble mix with resin coating is used around the base of the large street trees, so that water can infiltrate but it's not dusty or muddy. Always thought that was clever engineering, to get just the right mix to keep the spaces for water while still keeping structure.
posted by wilful at 5:02 AM on September 30, 2015
One of my (UK university researcher) friends watched the video and replied:
"Like gin encountering the stomach lining of a beleaguered academic."
posted by Wordshore at 6:01 AM on September 30, 2015 [3 favorites]
"Like gin encountering the stomach lining of a beleaguered academic."
posted by Wordshore at 6:01 AM on September 30, 2015 [3 favorites]
Asphalt and concrete are very different things, they're in no way synonyms.
In general use, yes. Engineers, as they are wont to do, sometimes refer to them as "bituminous concrete" (asphalt) and "portland cement concrete" (concrete). I spent a summer as a PennDOT inspector many years ago and that was only one of the many quirks of the PennDOT manuals.
posted by dforemsky at 7:05 AM on September 30, 2015
In general use, yes. Engineers, as they are wont to do, sometimes refer to them as "bituminous concrete" (asphalt) and "portland cement concrete" (concrete). I spent a summer as a PennDOT inspector many years ago and that was only one of the many quirks of the PennDOT manuals.
posted by dforemsky at 7:05 AM on September 30, 2015
*looks around*
Still not the post about non-edible uses of cheese. I had high hopes for this one.
posted by clavicle at 7:43 AM on September 30, 2015 [2 favorites]
Still not the post about non-edible uses of cheese. I had high hopes for this one.
posted by clavicle at 7:43 AM on September 30, 2015 [2 favorites]
(Maybe this will help a bit, clavicle.)
posted by moonmilk at 8:44 AM on September 30, 2015 [1 favorite]
posted by moonmilk at 8:44 AM on September 30, 2015 [1 favorite]
The common usage of the words asphalt, cement, and concrete is inexact. The exact usage is that a concrete is a material consisting of graded rocks selected to minimize the space between them held together by a binding agent which fills that space. Asphalt and (portland) cement are both binding agents. Popularly we tend to use the shortcut of calling the concrete by the name of its binding agent, but that's not really correct. There are also other exotic types of concrete which tend to be expensive because they use exotic binding agents that are a lot more expensive than asphalt and portland cement. (The OP may fall into this category once you learn how it's made.) And there are natural minerals called concretions which consist of pebbles fused together by geological processes.
posted by Bringer Tom at 10:24 AM on September 30, 2015 [1 favorite]
posted by Bringer Tom at 10:24 AM on September 30, 2015 [1 favorite]
this video is pretty awesome.
Ball Aerospace, as part of their stormwater capture strategy (they're located very close to Boulder Creek) installed a large test lot of permeable concrete in the office park near where I work. They dug out a giant dry well / drainage cache underneath it, and they must vacuum it regularly as it's pretty sandy/dusty/dry here and when I ride through that lot on my way to work, it's always spotless.
They installed it three years ago. It still looks as new as the day they installed it, and doesn't even have any cracks or signs of developing heave or potholes.
It regularly gets down to -25° C here in winter, and we have a vicious freeze/thaw cycle.
posted by lonefrontranger at 1:16 PM on September 30, 2015
Ball Aerospace, as part of their stormwater capture strategy (they're located very close to Boulder Creek) installed a large test lot of permeable concrete in the office park near where I work. They dug out a giant dry well / drainage cache underneath it, and they must vacuum it regularly as it's pretty sandy/dusty/dry here and when I ride through that lot on my way to work, it's always spotless.
They installed it three years ago. It still looks as new as the day they installed it, and doesn't even have any cracks or signs of developing heave or potholes.
It regularly gets down to -25° C here in winter, and we have a vicious freeze/thaw cycle.
posted by lonefrontranger at 1:16 PM on September 30, 2015
Bringer Tom:You'd be surprised where it freezes. NOLA was mentioned upthread. Last year we had two ice storms which shut down the entire city because every single bridge and a lot of ground-contact paved surfaces were frozen over with as much as an inch of ice.
1. No, I wouldn't be.
2. An inch of ice on top of the road still doesn't mean that the temperature 1" below the road surface is below freezing. In fact, it's fairly likely to be unfrozen. Ground temperatures are always higher than surface temperatures in winter.
3. The world doesn't end at the US' southern border, no matter what your pappy told you.
4. This stuff is used successfully in places that have occasional freezing temperatures. It's prolonged freezing temperatures that are a threat. I can tell you, as someone who's lived outside of NOLA: two whole days of ice in a decade or so doesn't really make NOLA the planet Hoth.
posted by IAmBroom at 4:39 PM on September 30, 2015
1. No, I wouldn't be.
2. An inch of ice on top of the road still doesn't mean that the temperature 1" below the road surface is below freezing. In fact, it's fairly likely to be unfrozen. Ground temperatures are always higher than surface temperatures in winter.
3. The world doesn't end at the US' southern border, no matter what your pappy told you.
4. This stuff is used successfully in places that have occasional freezing temperatures. It's prolonged freezing temperatures that are a threat. I can tell you, as someone who's lived outside of NOLA: two whole days of ice in a decade or so doesn't really make NOLA the planet Hoth.
posted by IAmBroom at 4:39 PM on September 30, 2015
Seems like this could be great for bike lanes since it would keep the surface dry, water could run off the main road onto the sides, and final drainage could be into drains along the side of the road - possibly you could get rid of the big surface storm drains entirely.
posted by RustyBrooks at 5:44 PM on September 30, 2015 [2 favorites]
posted by RustyBrooks at 5:44 PM on September 30, 2015 [2 favorites]
The world doesn't end at the US' southern border, no matter what your pappy told you.
Um, what? Last time I looked Louisiana was above the US' southern border.
posted by Bringer Tom at 6:10 PM on September 30, 2015
Um, what? Last time I looked Louisiana was above the US' southern border.
posted by Bringer Tom at 6:10 PM on September 30, 2015
THE CONSTITUTION IN THE 100-MILE BORDER ZONE
posted by ChurchHatesTucker at 6:35 PM on September 30, 2015
posted by ChurchHatesTucker at 6:35 PM on September 30, 2015
So the constitution, does it cause or prevent freezing?
posted by Bringer Tom at 6:38 PM on September 30, 2015
posted by Bringer Tom at 6:38 PM on September 30, 2015
Bringer Tom: "The world doesn't end at the US' southern border, no matter what your pappy told you.
Um, what? Last time I looked Louisiana was above the US' southern border."
I think that was the point.
posted by RobotHero at 7:21 PM on September 30, 2015 [1 favorite]
Um, what? Last time I looked Louisiana was above the US' southern border."
I think that was the point.
posted by RobotHero at 7:21 PM on September 30, 2015 [1 favorite]
Conservatives say it causes it, Liberals say it prevents it. (In the USA. YMMV. HTH.)
posted by ChurchHatesTucker at 7:22 PM on September 30, 2015
posted by ChurchHatesTucker at 7:22 PM on September 30, 2015
I think that was the point.
In that case the point makes no sense whatsoever, since I said nothing about being inside or outside of the US. Obviously NOLA is part of the US, so how does observing that it sometimes freezes here demonstrate an assumption that nothing exists even further south?
posted by Bringer Tom at 5:32 AM on October 1, 2015
In that case the point makes no sense whatsoever, since I said nothing about being inside or outside of the US. Obviously NOLA is part of the US, so how does observing that it sometimes freezes here demonstrate an assumption that nothing exists even further south?
posted by Bringer Tom at 5:32 AM on October 1, 2015
You replied to this:
IAmBroom: "Sometimes they build civil projects in places that don't freeze."
With this:
Bringer Tom: "You'd be surprised where it freezes."
And that's where you provided your example of a place that we're supposed to be surprised that it froze. Because it was in direct response to his claim, IAmBroom took your examples as an attempt to prove that it would be impossible to build a civil project in a place that doesn't freeze.
posted by RobotHero at 8:22 AM on October 1, 2015 [1 favorite]
IAmBroom: "Sometimes they build civil projects in places that don't freeze."
With this:
Bringer Tom: "You'd be surprised where it freezes."
And that's where you provided your example of a place that we're supposed to be surprised that it froze. Because it was in direct response to his claim, IAmBroom took your examples as an attempt to prove that it would be impossible to build a civil project in a place that doesn't freeze.
posted by RobotHero at 8:22 AM on October 1, 2015 [1 favorite]
You forgot the other comments specifically speculating about the usefulness of this concrete in New Orleans, which is why I pointed out that it does freeze in New Orleans. I was making no judgement at all about whether the product would work in New Orleans, or even whether there are other places (like HEY OUTSIDE THE USA, USA, USA!!!) where it might really not freeze, only that in New Orleans, a place most people think it doesn't freeze, it does sometimes actually freeze. I do not see how that justifies a snide suggestion that I think the world ends at the US border maybe because that's what my Pappy told me.
posted by Bringer Tom at 9:20 AM on October 1, 2015
posted by Bringer Tom at 9:20 AM on October 1, 2015
So the constitution, does it cause or prevent freezing?
It will freeze peaches of the 1%, but that's about it.
posted by jamjam at 9:27 AM on October 1, 2015
It will freeze peaches of the 1%, but that's about it.
posted by jamjam at 9:27 AM on October 1, 2015
Bringer Tom: "You forgot the other comments specifically speculating about the usefulness of this concrete in New Orleans, which is why I pointed out that it does freeze in New Orleans."
I didn't forget them, I ignored them, because they weren't relevant to explaining why IAmBroom interpreted your response the way that he did.
posted by RobotHero at 11:01 AM on October 1, 2015 [1 favorite]
I didn't forget them, I ignored them, because they weren't relevant to explaining why IAmBroom interpreted your response the way that he did.
posted by RobotHero at 11:01 AM on October 1, 2015 [1 favorite]
Mod note: Folks, please drop it, over the parsing of that one comment.
posted by LobsterMitten (staff) at 11:09 AM on October 1, 2015
posted by LobsterMitten (staff) at 11:09 AM on October 1, 2015
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1. Doesn't work in freezing areas.
2. Costs 2-3x what normal asphalt does.
3. We can't apparently be assed to spend 1x current asphalt costs.
posted by absalom at 5:05 PM on September 29, 2015 [22 favorites]