Porous Paving: Open Cell Concrete Block
by Lloyd Alter, Toronto on 07.25.06
One only has to step outside onto any parking lot to understand the meaning of "heat island" as pavement across the continent becomes too hot to touch. Asphalt is a fossil fuel product, it retains heat and is impermeable- a little rain and all the dirt, pesticides oil and dog crap wash into the storm sewers and waterways. Porous pavements let air and water pass through, filtering pollutants on the spot. Right now, their best feature is that they are cool. Azure Magazine's Material World section recently covered a series of options for paving that beat the heat and don't hold water. Open Cell Concrete Block is one solution- concrete paving systems designed to take the load of vehicles yet with enough open space that water can drain and grass can grow.
The Hastings Checker Block shown above is 70% grass.
Hanover Architectural Products makes Eco-Grid (39% open)
Belgard makes Turfstone. All of these permit drainage to the underlying soil, reducing stormwater runoff, and permit grass to grow through. And, all are cool underfoot. ::Azure
This company makes a similar paver, for low-traffic areas, such as parking lots.
http://www.invisiblestructures.com/
They did the ginormous parking lot for Reliant Stadium in Texas, and now they can actually use the parking lot for summer fairs, which were not possible on the old Astrodome lot.
http://64.207.55.3/FMPro?-db=project%20profiles&-format=record%5fdetail.htm&-lay=layout%20%231&-sortfield=project%20name&-sortfield=product&-sortfield=state&-sortfield=Application&-op=eq&project%20name=reliant&-lop=or&-max=20&-recid=32780&-find=
LA: this is a series, watch for tomorrow!!!
I've seen these lots used in a few places. Another nice aspect is that if and when the pavement develops a few buckles or if the design isn't quite right, instead of getting huge puddles of standing water, the open space allows the water to drain (slowly). This is especially good in winter, when standing water means slick ice patches in the parking lot.
Being in a rural area, I am also familiar with another, more humble permeable paver: gravel.
Can you snow-plow it in the winter?
LA: I have seen it plowed and shovelled here in Toronto.
Developers may object to use of permeable pavement on the basis of future cost liability; should the permeation feature diminish, re-paving after a short design life would be required at a higher future cost. When I have heard this arguement it sounded specious. My suspicion was that the real reason to oppose was that the total amount of runoff detention per acre per 25 year storm was under zoning spec with permeable lots alone, meaning that the developer also had to foot the bill for a smaller detention basin. That translates to higher total cost in labor/materials than for just a big whomping basin.
Hi,
Sorry, it is not the solution. The braking distance sare getting longer, women can't walk on high heels, it is awful to ride to push a bike on it....
I don't think braking distance is a great concern in a parking lot.
There are _so_ many places where a permeable solution could be used, although I do wonder about the effects of under-car pollutants (oil and various fluids). I suppose it would be easy enough to plant with pollutant-eating plants.
Recycled plastic would be better.Stone is heavy and takes lots of energy to make and transport and install.
http://www.permaturf.com/advant.htm
Zoning laws should limit parking and retail should charge to park,money can be spent for better lots.Will there be gas to go to the mall anyway?Gas pumps will stop working when they go past $9.99.
Braking distances shouldn't be a big deal in a parking lot - just post a speed limit.
As for high-heels - oh brother, cry me a river!
Never had a problem with a bike on 'em - you just glide right over.
I work for a company who just built a new office building (we outgrew our old one) with an eco-friendly design. We used three different types of pervious pavement systems, among other things, to see how they work in relation to one another. We didn't use the grasscrete system shown, but we did use pavers with 10% void space filled with open-graded gravel. They work great so far, we haven't had problems with women in high heels, and you can plow them. (You can plow the gravelpave product as well, but only if the ground is frozen.) We've documented all of our design techniques and are setting up monitoring this summer- if anyone's interested in the info, you can e-mail me at jb385(at)cornell.edu.
Dave- in response to your second point, don't forget that the alternative is to have the pollutants sheet flow to a concrete channel directly to our streams. Giving it time to bind to the underlying soils helps the water quality downstream.
Thanks Lloyd!
This is one of my favorite subjects!
Ok, I love this stuff, but a devil's advocate question comes to mind:
How does the environmental impact of paving a lot or alley once every 20 years, weigh against the impact of now having to mow your parking lot/alley 2-3 times a month?
This is the same beef we have against golf courses and giant 'lawn-parks', right?
Clearly these companies should also provide a type of sedam or grass that requires little or no mowing.
How friendly is this for handicap people? Wheel chairs, canes, crutches, etc. I can imagine not so safe for the latter two. Why not half a parking lot 'normal' and have it drian into one like above?
Jilt,
Actually, I've walked on it with my mom and her friends in chairs, on crutches, and with canes.
We were in a disability parade, and no one even noticed, because the soil was level with the bricks, so everything was basically even. People had more trouble once we moved into a normal grassy field.
Aigars Bruvelis: if you are going to have a reason to oppose a future technology, it might be wise to think before you act. As far as I know, in the US, there is a speed limit of no more than 15mph in any parking lot. Maybe it's a state law, but I see no need to worry about breaking insanely suddenly. If your worried about breaking distance because people are driving fast, then fix the speeding. Last time I checked bikes ride pretty good on flat surfaces.
Carl: answer me this Carl. What's the cost of an un-inhabitable Earth. Does it outweigh the cost of paying an illegal immigrant to mow your parking lot at night? (Well I guess it could be someone at minimum wage huh...)
I never understood why there is so much opposition to eco-friendly technology.
What are the specific environmental tradeoffs of using this surface over asphalt or concrete? True, the heat island effect is greatly mitigated, as is the stress upon nearby streams and water treatment plants.
However, the watering requirements of a large parking lot would be huge, with a large irrigation system to match. And doing maintainance on pipes buried under heavy concrete is going to require a backhoe, right? What about the huge cloud of ozone that gets released when the surface is mowed? What about the labor costs involved in mowing that surface? Of course, if we can make a robotic vacuum cleaner, then a robotic lawn mower can't be too far off...
Carl,
Don't forget that there are more environmental impacts from paving than just the act of paving itself. The runoff from impervious surfaces is both a higher volume and faster than runoff from a grassed surface. This higher-energy water causes stream erosion, which degrades habitat (both in- and out-of-stream) and increases sedimentation downstream. One of the biggest problems facing many of our water resources (besides having too many demands on them) is sedimentation/water quality.
Webs,
We can't be certain a technology is more eco-friendly until all the factors have been considered. Sustainability requires evaluating as many costs as possible.
Simply jumping from one paradigm to another without lookng very well, may land us in more hot water than before.
We can see this playing out already in the rush to biofuels.
These sites, if designed well, actually don't require irrigation, as they'll catch runoff from surrounding parking areas and buildings. In addition, the sites allow for groundwater infiltration, which keeps the groundwater table where it should be, and surrounding areas may require less irrigation due to this.
they've been using this all over china for years and years. i was really depressed when i came home and did't see it anywhere.
Why assume it has to be mowed? There are many types of plants that are low-growing. Many of these can be seen at your favorite home store sold as "ground cover."
Webs...
"I never understood why there is so much opposition to eco-friendly technology.
Carl stated that he was taking a 'Devil's Advoccate' position.
One takes such a postion in order to refine one's own real position.
You can basically ignore water costs or use - the point is you don't water this - it get's soaked by rain. In a dry climate it dries up until needed, you use appropriate turf.
I think the "high heels" and "cane" problem is greatly exaggerated, these things are not pits, they are very stable...
I saw a driveway made of this, but I wonder about a) the long-term effect of car droppings (fuel, oil, etc.) on the earth beneath and as a motorcyclist I have the more mundane question of my kickstand.
The house I saw had it in the front--instant front yard where there was none before. Very nice!
well, its not too late. we can still save our planet by starting to make your own pavement, others will follow once they had seen you pavement.
I say we should be more forthcoming to companies that are trying to develop ways to offset our destruction of the planet. Cause lord knows there still aren't a lot of people lifting their fingers.
Another question is around here all new development requires a catch basin for run off. You know a usually fenced in area that all the surface run off goes and forms a pond. How is that any different than something like this?
It isn't, except that most commercial building are going to have a parking lot anyways. So with using this technology, that basin for catching run-off is not needed, or at least the companies won't have to build as big of a run-off basin. And those run-off basin's are a cost that companies have to take when constructing a new building. So in that respect companies can save money implementing this.
Does anyone else find it interesting that two of the topics with the most discussion are related to grass? First mowing and chemical use on lawns, and now grassy parking/driving surfaces. Something about the itchy green stuff trips peoples triggers here on TH!
Permiable Pavers - the pavers are produced from products originally from the earth. Concrete for that matter is considered clean fill. The manufacturers created the permiable paver to help remedy the water runoff problem. We install pavers in New England, one of the toughest areas due to the changes in climate. In New England, new homes along the waterfront are limited to such products due to the environmental restrictions. Choices exsist other than the turfstone type that allow grass to grow through. A normal interlocking paver install will allow rainwater to permiate and not create the runoff issues mentioned. It will never be least expensive, it is in fact stone setting, but pavers make for seamless additions and minor repairs due to frost and heaving are invisable. Asphalt or solid cement will wear and crack with time. Concrete pavers are usually warrantied for life through the manufacturer and if installed correctly should be virtually maintenance free. There are also solvent free sealers available to protect from oil and fluid stains in driveway areas. It is truely an avenue to be considered by the consumer. ICPI has extensive information on their site.
I'm planning to use this porious paving for my diveway because I like the look with the grass. Can anyone give me any input on the plus and cons compared to traditional asphalt?
Thanks
Pervious Concrete Pavements would provide solutions to many of the problems associated with an open-cell concrete block. I am a Concrete Contractor in Tampa Fl, and I have seen many demos at trade shows and conventions.
Contact me via www.renoconcreteconstruction.com if you have a project within 100 miles of Tampa FL; and are interested in using Pervious Concrete.
hi.
is there a way to compute the volume of rain water that'll be collected/pass through the paving? or does it depends on the paving that im going to get..?
if there is a way to know.. how?
reply, emai or post comment. thanks.
Hi,
I am currently doing a deisgn project relating to stormwater management on our university campus. Alternate paving materials, especially for areas such as parking lots will make a big difference in the amount of runoff. I have a few questions and am wondering if anyone has any tips:
1) I think someone already mentioned this, but: Would speical considerations have to be taken with reguards to the material under your parking lot, for decontamination purposes? Will all the oil, gas, etc, just sit in the soil, or does it break down eventually?
2) Does anyone know of (preferably) Canadian companies who would do things like this? I am looking for hard numbers to compare with costs of traditional paving.
Thanks
lol
I completely agree with all that here is told
So you can find the information on it on my search resource
I completely agree with all that here is told
So you can find the information on it on my search resource
you can be even more eco-friendly by using reclaimed bricks (the kind with 3 holes in them) placed sideways, so that the holes run vertically allowing water through.
Since all my neighbours have now laid waterproof landscape fabric or solid paving I have all their runoff flooding me. I'm planning to replace the small areas of paving I have around my boundaries with bricks. I'm going to use reclaimed gravel to create a drainage are a few feet below, topped with bad soil, then water permeable fabric to stop weeds taking a deep hold. Then I plan a 1inch base of sand (reclaimed from the existing paving base) top with another inch of 50/50 sand and garden soil to bed the bricks into. I'll put the 50/50 mix in the brick holes to encourage succulents and native herbs to grow through as far as the weed membrane below..
I realise that a parking area would most likely need a more stable base but for my own lighter use purposes it is ideal and should prevent localised flooding during heavy rains, as well as capturing precious water during dry periods. Well, that's my theory, but I make no scientific claims. I'd love to hear of others who have had success with similar techniques :)
ps. people keep talking about mowing the grass but if the area is used frequently, by cars or people, the action of being squished tends to keep many of these areas short anyway. I guess it depends where you live and the type of grasses you have. I will be pulling up any grass that grows in mine and encouraging things like moss, herbs, succulents... whatever will take hold really.
Centiped grass grows very close to the ground and needs little to no mowing where light traffic is present. I mow mine once a year in Hawaii. The seed is not cheap, but it saves a lot of mowing.
The feedback here is enlightening on logical pavements. When constructed properly, permeable pavement systems also prevent the raising of water temperatures in aquatic habitats. Rain water run off from hot impervious pavements can enter streams and raise water temperatures. On the other hand, permeable pavement systems allow rain water to filter through its base structure, cooling it well before reaching the aquatic habitats. Elevated water temperatures from impervious pavement run off can kill aquatic life.
Then too, permeable pavement systems can reflect heat and cool faster over night. Also, Developers are now building in the space once alotted for an onsite detention pond, thus increase lease space. Cisterns with sump pumps are being installed as part of the system to store rain water to be used as irregation.
Trees do grow well in these systems and are being used to shade parking lots.
These are just a few more of the benefits of this environmentally logical way to pave.
These are just a few more
I completely agree with all that here is told.
How would each of you feel about making a pervious concrete block (which prevents the need for retention ponds and helps filter rain water) that uses recycled crushed materials (block, concrete, aggregates,etc.) with white cement (to reduce the amount of lighting needed), with fly ash (to help get rid of some coal burning plants' wastes), that would be easier to install rather than pouring concrete from mixer trucks? Would this be of interest to any of you? I am currently designing a block including all of this material to help make a very "green" product and any feedback is appreciated. Thanks
In response to Drew, I came across a company that is already manufacturing and installing pervious concrete. http://www.envirocreteinc.com/about%20us.htm
It's an interesting concept and one I hope takes off and replaces all the impervious asphalt parking lots and other paved surfaces.