I would like to commend you for an excellent video, that explains what is "just right"! I am sure it was time consuming, but glad you painstakingly made the effort.
Wow.. geat and educational.. Thanks for taking the fime . I know this video is very old . But its exactly what i was looking for . Cheers from Melbourne Australia
You sir, are a teacher...:)...Thanks so much for the info...I've been doing concrete work for decades, but we don't get any call for this type, but I can think of some good uses for it...
Yes, pervious concrete and other permeable pavements are great at capturing water and returning it to our continuously diminishing groundwater storage. By keeping our groundwater levels up, we not only get to continue to rely on them for our water usage, but it also keeps the ground from sinking (subsidence) and further contributing to flooding potential. Unfortunately lately there has been more reports of devastating urban flooding in the U.S. and other parts of the world. According to this article from June of 2022, www.theguardian.com/environment/2022/jun/07/slow-water-urban-floods-drought-china-sponge-cities? : "Globally, urban flooding has become particularly acute as the land area covered by cities worldwide has doubled since 1992. Researchers from Johns Hopkins University calculated how impervious surfaces increase flooding: every time a city increases coverage of absorbent soil with roads, pavements or car parks by 1%, runoff boosts the annual flood magnitude in nearby waterways by 3.3%." And according to this article from way back in July 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC1257665/ : "Paving Paradise: The Peril of Impervious Surfaces In the United States alone, pavements and other impervious surfaces cover more than 43,000 square miles-an area nearly the size of Ohio-according to research published in the 15 June 2004 issue of Eos, the newsletter of the American Geophysical Union. According to the nonprofit Center for Watershed Protection, as much as 65% of the total impervious cover over America’s landscape consists of streets, parking lots, and driveways. Another big problem for urban areas is the flash flooding that can occur when heavy rains fall over a city, according to hydrometeorologist Matt Kelsch, an authority on urban flash flooding with The University Corporation for Atmospheric Research in Boulder. Since runoff from an acre of pavement is about 10-20 times greater than the runoff from an acre of grass, Kelsch says impervious surfaces can quickly trigger devastating floods that can produce a host of their own environmental health hazards."
That's a great video, I was thinking about paving my driveway using this technique on my own. However, I'm concerned it might break during winter. I live at a high latitude, and it rains a lot in winter. If some water gets trapped and freezes, the whole thing might crack. Thanks for the info though, very educational
Thank you! Human scale! This makes it useful, helpful to people in their everyday lives. Practical. The opposite is the typical ripoff 'proprietary blend in a special machine' along with a monthly sign-up for more supplies. The collective thanks and honors you! "I don't wanna be a product of my environment, I want my environment to be a product of me!"
I've done these in stepping tiles in my front yard. One thing is since there is a fine amount of cement, I would cover with plastic for a few days so it drys slowly.
Yes, generally covering pervious concrete with plastic as soon as it is placed is a good idea. Please check out a couple of our other videos for more ideas on how to install and cure pervious concrete: 'How to Place a Pervious Concrete Path' th-cam.com/video/y0m0yrG0ghE/w-d-xo.html 'Avoiding Raveling of Pervious Concrete' th-cam.com/video/xkkgTXbYvBI/w-d-xo.html
Thank you, John! Pervious concrete holds up very well in cold climates. It has been used extensively in the northern U.S. and Canada for decades, primarily for parking lots. This topic is on my list to write an in-depth blog about since the question does come up often. There are a couple of caveats like good drainage, typically lots of drain rock, should be provided below the pervious concrete pavement. Also modified snow plows should be utilized and deicing salts not used or at least used with caution. However there is at least some evidence that pervious concrete can actually be safer, cleaner in snowy conditions since ice is less likely to build up on its surface unlike with more ordinary pavements.
A video detailing our results, with closeups and permeability shots, from a few different projects is one we have been wanting to produce for some time now. Hopefully we can get to it soon...
Sand is used I. Conventional concrete to bond the cement. Will the removal of sand not substantially degrade the compressive strength of the final product?
Yes, pervious concrete can have less strength than traditional concrete. However, with the use of admixes, careful mix design and proper installation in the field the strengths of pervious concrete can be close to and similar to traditional concrete pavement, which usually achieves from 2500 psi (17.2 MPa) to 4000 psi (27.5 MPa) compressive. Even without special admixes and a deep understanding of mix designs, pervious concrete as demonstrated in this video, typically will have way more than adequate strengths for most pedestrian and light vehicular applications. Concrete pavement most commonly fails because it cracks and becomes unsightly, which usually has little to do with its strength. One major contributor to concrete cracking is that concrete shrinks, but because pervious concrete tends to shrink considerably less than traditional concrete, it can crack less. Perhaps the most telling example of pervious concrete's more than adequate strength, is that its most common application in the U.S. has been for parking lots. Moving forward we are demonstrating it is even possible for pervious concrete to be stronger than typical concrete pavement. We are achieving compressive strengths sometimes well over 4000 psi with our very fine pervious concrete PerkTop & PerkGrout.
Could you tell what gradation of rock gives a best result ? I need to make driveway in front of my garage that will take 7000kg truck and yet I would like to have smooth surface like on your video.
For really strong pervious concrete, technically higher compressive strengths are attainable with very fine aggregates/ coarse sand. However, the permeability is significantly reduced using very fine aggregates at driveway thicknesses. So, unless you are going to utilize a two step process like with our PerkTop (perviousproducts.com/perktop/), about the finest aggregate you could use would be about 1/4" (6 mm) and possibly a little finer if the design is carefully implemented. Often asphalt plants stock this gradation of aggregate as a manufactured/ crushed rock, which would be fine. Pervious concrete mixes using 1/4" or 3/8" aggregates will provide more than adequate strength for 7000+ kg (15,500+ lbs) trucks. They should be poured at least 5 1/2" to 6" thick over several inches of crushed, coarse aggregate and if there is a lot of this type of traffic, then thicker pavements could be necessary. When engineers, architects and other specifiers reach out to us to see if our PerkTop is suitable for heavy vehicles like yours and fire trucks in particular, we like to reference this work put out by Timothy Lawrence and Monique Myers of the 'California Sea Grant College Program', titled 'Emergency Services and Stormwater Management': "California allows fire engines to have a single axle weight of 23,000 pounds on the steering axle (2 tires/steering axle) and 24,000 on the drive axle. Tandem axles can be up to 48,000 pounds and tridem axles up to 54,000 pounds. All fire engine drive axles have dual tires (4 total/axle), so each steering tire can support up to 13,500 pounds (54,000 ÷ 4). Determining the support capability of any surface is based on the displacement of the weight over the surface area in direct contact with the vehicle tires. The contact surface area can vary by tire size, brand and inflation pressure. An example of the weight distribution of a fire engine in psi for a tire commonly found on fire engines is the Goodyear G286 12R22.5. Inflated to 90 psi, the average surface area of tire contact is 95 in 2(613 cm2). The weight displacement for each tire, if the maximum allowable load on a steering axle is 12,500 pounds or 357.14 psi, gives a 7-fold safety factor for a typical pervious concrete pavement rated at 2,500 psi."
This was an EXCELLENT video, thank you for this. One question, if you end up seeing this - how strong is this material once done? It seems to me it might be subject to cracking if it's too thin, so it would be good for some guidance on how thick I need to make my piece (and how much it might be determined by aggregate size). Thanks!
Thank you for the props! You bring up several good questions. The short answer to how strong pervious concrete is... is that it's compressive strength is typically around 2500 psi (17MPA) to 3000 psi (20 MPa), which can be a little lower than ordinary residential concrete with typical strengths ranging from 2500 psi to 4000 psi. Pervious concrete even at the lower end, at 2500 psi, is still very strong and provides over a 7-fold safety factor for supporting the weight of a firetruck! In regards to how thick the pervious concrete should be... generally it should be at least as thick or a little thicker than ordinary concrete would be in the same application. Typically it should be at least 3 1/2" (90mm) for pedestrian areas and 5 1/2" (140mm) thick for vehicular. Soil type and thickness of the base material play a part as well. However we have successfully placed pervious concrete as thin as 2" with a couple special considerations. If you are using your pervious concrete for some other application, not as a pavement (or perhaps as an overlay on an existing pavement), then a general rule of thumb is to make the thickness of the concrete at least 3 times the size of the aggregate. So for a 3/8" (10mm) pea gravel the thickness should be at least 1 1/8" (30mm). As was pointed out and lightly touched upon in the video, just about any size aggregate could work for making pervious concrete, however generally some loss in strength can be expected the smaller the aggregate gets starting below 1/4" (6mm) in size. Given that very fine aggregate pervious concrete is our specialty, we have developed mix designs that offset this decrease. There are many variables that can affect the ultimate strength of pervious concrete and mitigate potential for cracking. Please keep an eye out for more videos and blogs, on our website, perviousproducts.com/ coming from us shortly that will attempt to address these questions in far greater detail than I can here. Ryan
Wonderful info thanks! My initial project will be really light duty (exit chute for drainage tile into the yard to prevent erosion) but I would love to find more uses for this, so this is good info. Thanks again!
I think this is a good solution to resurfacing a walkway. Install bricks on the edge of the sidewalk two bricks tall and use an epoxy adhesive to make the bricks stick to the sidewalk and the next brick. Then use an acid etching concrete cleaner to prep surface of concrete. And also an adhesion promotor rolled on lightly with a roller and cut in the edges with a cheap brush. Directly after it dries use this mix to pour a 1-2 inch layer on top of the sidewalk and the bricks on the side will act as a border and a wall too for mulch and grass. The water will drain down and out from in between the bricks. Only use one brick if you don't want a tall edge and pour the mix to the height of the 1st brick evenly without getting a bunch of stuff on the brick but you can wash it off with a brass wire brush and hose easily just try not to wet the wet concrete mix. This is my solution to a sidewalk with flat spots. I should either resurface the sidewalk first before this mix goes on top and make a grade towards the side to let water flow off the edge of the sidewalk in between the bricks and maybe use a concrete blade on my grinder to cut a few squares or circles and install basic plastic drain covers as the stuff under the sidewalk is all sand. I live on the beach and all we have is sand here and we are only 6 feet above the water table. But oh well. I am going to just wing it. I might cut a few circles and install some drains that connect to a small diy French drain underneath the mulch bed on the side of the sidewalk or install a few catch basins and use this around the housing and leave room to put the drain covers on but we will see how far my motivation goes that day. Lol
Pervious concrete holds up very well in cold climates. It has been used extensively in the northern U.S. and Canada for decades, primarily for parking lots. This topic is on my list to write an in-depth blog about since the question does come up often. There are a couple of caveats like good drainage, typically lots of drain rock, should be provided below the pervious concrete pavement. Also modified snow plows should be utilized and deicing salts not used or at least used with caution. However there is at least some evidence that pervious concrete can actually be safer, cleaner in snowy conditions since ice is less likely to build up on its surface unlike with more ordinary pavements.
Hey Steve, thanks for checking out our latest PerkTop pervious concrete installation! A couple of years ago we also installed a driveway around the corner at: 670 Stetson St. Moss Beach, CA 94038. And just down the road a bit a couple of months ago we installed a PerkTop driveway in tan color at: 608 Ruisseau Francais Ave. Half Moon Bay, CA 94019. A little further afield, we installed pervious concrete for significant portions of the large parking lot at the new Cadillac dealership in Colma, CA. Upcoming, at the start of the new year we will begin installing 57,000 square feet of pervious concrete for large portions of the new 'Veterans Memorial Parking Lot' in San Rafael, CA. We have installed countless other PerkTop projects in the San Francisco/ San Jose Bay Area. If you would like to check out any of those, let me know and I can provide a list accordingly. Thank you, Ryan
Adding fibers and/ or mesh to pervious concrete can be beneficial. Just about any type of fiber or synthetic mesh is compatible, except notably, do not use metal in pervious concrete. Metal, whether it is rebar, wire mesh or steel fibers (except stainless) will get exposed to water in pervious concrete and rust, corrode and expand damaging the concrete and becoming ineffective. Basalt rebar, fiberglass and other composite or coated rebar can be used in pervious concrete. We have also used anodized aluminum for doweling with success so far. In regards to the effect that adding fibers or mesh will have on pervious concrete it is difficult to quantify. In general one would want to measure for a higher tensile ductility, but since there aren't even any ASTM or other approved compression strength tests for pervious concrete, any tests will need to be set up and documented very carefully. Anecdotally, I will say pervious concrete samples that we crush for physical strength tests that have fibers notably stay together much better past failure and do not tend to 'explode' as much as samples without fibers. So the right type, combination and dosage of fibers should translate into a pavement that does not crack as much or as noticeably.
Generally it is a good idea to make pervious concrete a little thicker than ordinary concrete. So for vehicular use often 5.5" to 6" (14 to 15 cm) is adequate. Making it thicker helps to offset not being able to use reinforcing mesh. Since wire mesh or rebar would corrode quickly due to all the moisture moving through the concrete it is not recommended for pervious concrete unless it is coated or treated. Alternatively, non-metal fibers can be used for varying amounts of reinforcing. For more discussion of how thick to make pervious concrete for various applications: perviousproducts.com/thick-make-pervious-concrete/
Thank you for your response, I can't believe I didn't recognize the corrosion aspect my self :). Yes I have heard of the fiber additive. Anyway I'll check the link.@@perviousproducts6648
Yes, one can make pervious concrete with just about any size rock. The downsides to using coarser 3/4" (19 mm), or similar large aggregate, are that it can be more difficult to mix and finish, it will generally require more cement to achieve similar strengths, and the finished product is quite rough looking.
Though there are no standardized ASTM or other compressive strength tests for Pervious Concrete, typically when it is installed properly in the field one would expect it to achieve around 2500 to 3000 psi (17 to 21 MPa) compressive strength. This is on the lower end of more traditional concrete, but more than adequate for most vehicular and other applications. However, if the pervious concrete mix was designed very optimally, 4000 psi (27.5 MPa) compressive strengths can be attained. Even higher strengths are attainable with Pervious Concrete utilizing very fine aggregates, but this tends to significantly reduce its permeability at much thickness.
Pervious concrete can be installed using compaction with vibration. However one needs to be careful using this combination as it can very easily lead to over compaction and sealing up of the pervious concrete. Alternately, if the compaction with vibration is delivered a little too late to the fresh placed pervious concrete, it can damage it and lead to raveling (loose rock on the surface). Therefore the timing and compactive force need to be precisely and constantly monitored based on the specific pervious concrete mix and changing site conditions. All that being said, compacted and vibrated pervious concrete can produce the highest compressive strengths.
Yes, typically the cement used in pervious concrete is 'portland cement'. It can be any of the types of portland cement used in the U.S., Types I, II, III & V. However, other types of cement can also be used successfully in in pervious concrete. For instance, our PerkGrout product utilizes CSA (calcium sulfoaluminate) cement or 'rapid set'. The primary reason for its usage in this application is due to CSA cement's low shrinkage and therefore reduced cracking potential.
Pervious concrete can be trickier to place in high temperatures, but once installed high temperatures are not a problem at all. Even in full, intense sun where pavement temperatures can exceed 75 degrees Celcius (170 degrees Fahrenheit) pervious concrete, just like ordinary concrete will do fine. For tips on how to place pervious concrete in high temperatures, check out a couple of our other videos: th-cam.com/video/y0m0yrG0ghE/w-d-xo.html 'How to Place a Pervious Concrete Path' th-cam.com/video/xkkgTXbYvBI/w-d-xo.html 'Avoiding Raveling of Pervious Concrete'
Almost any rocks/ aggregate can be used successfully in pervious concrete. If the aggregate is dirty, dusty or has a lot of fines in it, this will tend to reduce the compressive strength of the pervious concrete, but not typically by an egregious or detrimental amount. If the aggregate is too well-graded, has too broad of a gradation, this can reduce the pervious concrete's permeability. Or using well-graded aggregate in pervious concrete can require less cement to get the desired permeability, thus reducing its compressive strength. We like to use clean, gap or narrow gradation aggregate for most of our pervious concrete in large part because we feel we can get more consistent and reliable results.
While it is possible to achieve those strengths in the lab, I am not aware of pervious concrete achieving compressive strengths of 30 MPa and higher in the field, on installations. It can certainly be used on lower volume roads, and with proper mix design and careful quality control while placing, pervious concrete can consistently achieve 25 to 28 MPa compressive strength. It is also possible to achieve flexural strengths greater than 4 MPa with pervious concrete, so this test could possibly be used instead of compressive. And finally pervious concrete pavement can be poured thicker to also achieve a higher overall 'Structual Number'.
Yes, the technical way to determine the ingredients of a pervious concrete mix: 1. Find the void content of the aggregate that will be used: voids, % = 100 ((S x W) - M) / (S x W) M = bulk density of aggregate lbs / cuft - dry rodded S = dry bulk specific gravity W = density of water (62.3 lbs/cuft) 2. Use the NRMCA pervious concrete mixture formula found at the bottom of this page: www.perviouspavement.org/materials.html Currently there are not any standards set for the minimum permeability of pervious concrete, that I am aware of. Traditional 3/8" (9.5mm) aggregate pervious concrete mixes, with around 20% voids, often drain in excess of 600"/hour (4.2mm/second)! Unless one is using the pervious concrete as a catch basin (not recommended), this degree of permeability is far in excess of what is actually needed to absorb even the most intense rain event. Strength is at least somewhat inversely proportional to permeability in pervious concrete, meaning that generally the lower the permeability, the higher the strength for any given aggregate. Since we often prefer to design our pervious concrete mixes using finer, 1/8" (3mm) and smaller, aggregate (primarily for aesthetic reasons) and these finer mixes can be weaker (though we use admixes to offset this), we like to achieve just enough permeability to even further maximize our strengths. 'Just enough' permeability for pervious concrete we feel like is over 200"/hr (1.4mm/sec), because it still looks impressive when some water is dumped on it. No, it won't immediately absorb the full contents of a ready mix truck filled with water, but it will quickly drink a bottle of water and more importantly infiltrate any type of rain event that may come along.
Nice topic how to get PERVIOUS CONCRETE consistong of cement, water and coarse aggregates. Regarding the open structure of pervious concrete, air and water can penetrate into the subsoil though voids existing with in the concrete. This kind of concrete has various physical and mechanical properties but also pasive green structural site for contributing wat is significant. PLANTY GOOD STRUCTURES we can do with pervious concrete.
Though there are no standardized ASTM or other compressive strength tests for Pervious Concrete, typically when it is installed properly in the field one would expect it to achieve around 2500 to 3000 psi (17 to 21 MPa) compressive strength. This is on the lower end of more traditional concrete, but more than adequate for most vehicular and other applications. However, if the pervious concrete mix was designed very optimally, 4000 psi (27.5 MPa) compressive strengths can be attained. Even higher strengths, 5000+ psi (34+ MPa) are attainable with Pervious Concrete utilizing very fine aggregates, but this tends to significantly reduce its permeability at much thickness. Determining a particular Pervious Concrete's proper water cement ratio (w/c) is tricky and is therefore we feel best finalized by visual confirmation using the descriptions in the video. The main reason for this is the amount of moisture in/ on the aggregate that is used. Inevitably this amount will vary within a pile of aggregate, throughout the course of a day, and from one day to the next. Just a small change in this water in the aggregate pile will make a significant difference in the water needed for the mix. For instance, the amount of water in an aggregate pile following a rain event can sometimes provide practically all the water that is needed for that mix. The types and amounts of admix used in the Pervious Concrete mix design will also have a huge impact on the water cement ratio. Because of this, we have designed mixes with below a .2 and above a .5 w/c, however most often we end up being around a .35 w/c. But please take the time to really dial in your own particular mix's optimal water cement ratio and keep an eye on your aggregate's water content!
Only if you do not have good drainage and water gets trapped in the concrete... other vids show about a 2 ft bed of large aggregate (in freezing climates)...
Yes, pervious concrete can be used in heavy traffic areas, even for large truck and bus use. For more info on this, check out our blog: perviousproducts.com/thick-make-pervious-concrete/
There are four (4) ASTM tests specifically designed for pervious (permeable, porous, thirsty) concrete: ASTM C1701 Standard Test Method for Infiltration Rate of In Place Pervious Concrete ASTM C1688 Standard Test Method for Density and Void Content of Freshly Mixed Pervious Concrete ASTM C1747 Standard Test Method for Determining Potential Resistance to Degradation of Pervious Concrete by Impact and Abrasion ASTM C1754 Standard Test Method for Density and Void Content of Hardened Pervious Concrete Currently there is not an ASTM test directly related to the strength of pervious concrete. Also even though there is a test, C1701, for measuring the permeability of pervious concrete, there is no consensus of what that rate should be. One can test pervious concrete using cylinder and cube molds for compressive, flexural, tensile strengths just like with ordinary concrete. The trick is documenting how the lab tests will accurately reflect the field results. There are so many factors that have an out-sized impact on the field results of pervious concrete, like weather, slight changes in the aggregate gradation or water, degree of compaction, et al. Determining the exact mix ratio for pervious concrete can be a challenge and varies depending on the aggregate used, weather and other onsite factors and what characteristics the installer and/or customer desire. The best approach can be to take our basic formula outlined in the video and start making small samples using your desired aggregate, carefully documenting the process and recording the results. We like to start this process by comparing permeabilities of various mix ratios.
Most Portland Cement are compatible with pervious concrete. All the different Portland Types seem to have the same attributes in pervious concrete as they do in ordinary concrete with no discernible deleterious results. The one factor to be wary of however is ASR (alkali-silica-reactivity) or other issues with the aggregate chosen. Fly ash, slag, silica fume and other pozzolans also seem to be compatible with pervious concrete in approximately the same substitution rates as they are in ordinary concrete. CSA (Calcium Sulfoaluminate) cements and no doubt, many others are also able to be used in pervious concrete.
Pervious concrete can be designed to support about any weight. Its most common application in the U.S. has been on parking lots. If designed and installed properly pervious concrete can also be used for higher and heavier traffic areas like bus stops, semi truck parking and even highways. We go a little deeper into this topic on our blog: perviousproducts.com/thick-make-pervious-concrete/ Pervious concrete will last as long or longer than ordinary concrete, 20 plus years. Pervious concrete has the potential of lasting longer because it tends to shrink less, therefore it generally cracks less than ordinary concrete.
As I mentioned in an earlier post, this important topic, of pervious concrete in cold climates, requires an in-depth blog or even its own video. Typically several inches of open drain rock are used for the base and drainage of pervious concrete. To see how deep this rock layer should be, check out our blog perviousproducts.com/pervious-concrete-base-material-depth/. Suffice it to say, in heavy freeze-thaw environments this drain rock layer should be deep enough to accommodate any rain and/or melted snow. The bottom line is pervious concrete has been installed all across the USA and Canada for over 30 years now with very good results, including in extremely cold climates.
@@perviousproducts6648 There are probably some areas where this type of pavement would not be advisable, or would need a modified base. For instance, where I live, a driveway might freeze 5 feet deep since it is kept clear of snow (which would otherwise act as insulation) and since the weight of traffic has a tendency to drive the frost deeper than usual. Also, the soil is impervious clay which holds water near the surface thruout the winter, effectively bringing the water table up to within 6 inches of the surface. Thus roads and driveways normally heave up several inches during the course of the winter. A typical open-graded base would fill with water and freeze, then the water would freeze within the pavement itself, possibly causing it to break apart. The only way I can think of which might work would be to build a very thick open-graded base, several feet deep, which would be placed entirely above the ground level and thus above the high water level, providing enough room for water to dissipate before it freezes. But even then I wonder if it would work.
@@ethanlamoureux5306 The other thing one could do in this situation is to add perforated drain pipes in the gravel base to redirect excess water away from the pavement. It is also recommended to use air-entrainment and/or other modified mixes in freeze-thaw climates. Again pervious concrete has performed well in heavy freeze thaw and there are even potentially some advantages to it over ordinary pavement. Light amounts of snow can dissipate faster, ice doesn't tend to accumulate on the surface making for safer pavements and less need for deicing salts.
To be on the safe side it is typically best to use aggregates that already have a history of being used in concrete. Sometimes aggregates can have deleterious effects and you'll want to have a minimum hardness. So I wouldn't use a soft stone, like sandstone, for the gravel.
There are many factors that go into determining the correct w/c (water to cement ratio) for a particular pervious concrete project: the type and size of the aggregate; timing between when it is mixed and placed; the quantities and types of admixes that are used (if any); and even the temperature and humidity make a difference, the warmer and drier it becomes, the slightly more mix water will be needed. It is best to become familiar with your specific mix design, documenting the amount of water needed for a particular amount of cement, to achieve the correct consistency when placed, knowing what too-dry, too-wet and just-right look like. Being familiar with how the consistency of the pervious concrete should look will help overcome the biggest variable for determining the amount of water, which is the moisture content of the aggregate itself. Most w/c recommendations are given off of ssd (saturated surface dry) aggregate, where the minimal aggregate pours are filled with water, but the surface is not visibly wet. This is a mythically impossible condition to achieve for anywhere but the lab. In real life (field conditions) the aggregate is going to vary considerably in wetness, even within the same pile, and the slightest changes in moisture make a big difference in the final consistency of the pervious concrete mix.
Bro please tell how to made the concrete sample because our project is same as you told Please tell me what the components are required and how to mix them Please reply bro
The short answer to how strong pervious concrete is... is that it's compressive strength is typically around 2500 psi (17MPA) to 3000 psi (20 MPa), which can be a little lower than ordinary residential concrete with typical strengths ranging from 2500 psi to 4000 psi (28MPa). Pervious concrete even at the lower end, at 2500 psi, is still very strong and provides over a 7-fold safety factor for supporting the weight of a firetruck! However there currently are not any ASTM or other certified tests for determining the compressive strength of pervious concrete. I believe this is so, in large part because there are just too many variables in the mixing and placing of pervious concrete. Unlike ordinary concrete, just because a certain result is obtained for a specific pervious concrete mix design in the lab does not in any way guarantee the same result in the field. Slight changes in the water content, the weather, timing of the placement and compaction differences are all factors that will significantly influence the final strength of pervious concrete.
Pervious concrete can be made from lighter weight material, but using perlite will not produce a very strong mix. It probably will not be strong enough even to walk on, but might be suitable for some type of pottery or other decorative applications. Some expanded shale/ clay can make suitable pervious concrete pavement.
I found green ant builder create this type of product using plastic waste for mixing material. I really love the idea, I want to bring this idea to my cummunity, but they charge this tech with high price, can you please teach me how to make previous concrete to use for paving road? I would love to discuss this idea
The little bit we experimented with incorporating plastic waste in our pervious concrete, it did not yield promising results. It may be possible to substitute a portion of the aggregate with recycled plastic in pervious concrete without negatively impacting the strength too much. However, since pervious concrete needs to be optimized to be suitable for road traffic, incorporating plastic waste into it would probably bring us further from that goal of using it in high traffic applications.
@@perviousproducts6648 by far greenant product only suitable for side walk or maybe for some park or garden, they also make a interlocking brick with slightly different material mix for home wall, this is really interisting for me
Some plastic could be incorporated into pervious concrete, but it would need to be kept to a somewhat minimal amount. Plastic in too large quantities will lower the strength of the concrete.
There can be many ways to increase the strength of pervious concrete. However before too much effort is invested in optimizing the strength, one needs to ensure the quality control for the entire installation process is really dialed in. Most of the variance in pervious concrete strength being placed today is due to to inconsistent installation, so much of it is not reaching its optimum/ designed-for strength to begin with. Once one has a firm understanding of their current process and mix ingredients, including the aggregate characteristics and its relationship to binder and water ratios, then one can begin further optimizing the strength of the pervious concrete mix. Utilization of some of the same principles of achieving high strength concrete can result in greater compressive strengths in pervious concrete. To increase flexural strength or the modulus of rupture, arguably the most important factor for a pavement, addition of acrylic and/ or certain fibers can yield good results.
One can add a small amount of fine aggregate (sand) to pervious concrete, but obviously the risk is if too much is added and it then becomes impervious. Controlled amounts of fine aggregate are sometimes added to pervious concrete, depending on the coarse aggregate that is used and if a little higher strength or resistance to freeze-thaw damage is desired. On the other hand we usually make our pervious concrete or at least our pervious concrete topping out of all fine aggregate. By using the coarse end of fine aggregate (sand) we make a very smooth, attractive pervious concrete. The best thing is to test different aggregates and combinations with varying amounts of cement and see what works best for your particular application. Compare permeabilities, strengths and aesthetics. Have fun!
Taking the sand, fine aggregate, out of ordinary concrete is generally what produces pervious concrete. However, it is possible to add very small, controlled amounts of sand back to the pervious concrete mix. This may be advantageous to reduce the permeability somewhat and gain strength and durability in mixes containing particularly large coarse aggregate or possessing 'too much' voids.
The 'setting time' is similar to ordinary concrete, typically an hour plus for initial set. However the 'working time', the time one actually has to place and finish, for pervious concrete is much less than ordinary concrete. It can be as low as a few minutes in less than ideal conditions. Please check out a couple of our other videos for an in-depth answer to this: th-cam.com/video/y0m0yrG0ghE/w-d-xo.html ("How to Place a Pervious Concrete Path) and th-cam.com/video/xkkgTXbYvBI/w-d-xo.html ("Avoiding Raveling of Pervious Concrete).
There are a lot of areas that could benefit from using pervious concrete to minimize occurrence of flooding. It is helpful in two ways. To begin with pervious concrete slows down or eliminates entirely rainwater from running off the pavement. Then the water that is absorbed by the pervious concrete slowly makes its way through the subsoil and recharges the groundwater. Keeping the groundwater, which is often relied on for domestic use, full is important because if it drops too low subsidence can occur. Subsidence is when the ground actually sinks and lower ground of course is more prone to flooding. Subsidence is a permanent, irreversible process and if too much occurs the ground can become impermeable and unable to absorb more groundwater. Large portions of the city of San Jose, California in the U.S. have sunk 13 feet (4 meters). Recently Jakarta was named the fastest sinking city in the world, www.bbc.com/news/world-asia-44636934, with parts of it sinking as much as 25 cm a year!
Pervious concrete when installed correctly performs well in very harsh freeze-thaw environments. Please see earlier comments on this thread in this regard.
I just want to tell you that this is an absolutely amazing video. Can't describe how immensely helpful you've been.
Thank you so much! It can take a bit to put these videos together and so it is always gratifying when hearing feedback like yours.
Man, i cannot describe how good is this video. Very instructional, and helped me a lot.
Finally, a video that explains the consistency the mix should have. Well done!
Having all the examples side by side was a great idea and it really helped when actually making it. Great video and editing work!!
I would like to commend you for an excellent video, that explains what is "just right"! I am sure it was time consuming, but glad you painstakingly made the effort.
I’m
Wow.. geat and educational..
Thanks for taking the fime . I know this video is very old . But its exactly what i was looking for .
Cheers from Melbourne Australia
Sir you saved the world
Respect from India
Thank you so much. Was doing a search and landed on this. Much appreciated.
You sir, are a teacher...:)...Thanks so much for the info...I've been doing concrete work for decades, but we don't get any call for this type, but I can think of some good uses for it...
Game changer for water conservation out here in the western states and helpful in reducing flooding! 🙏🏻
Yes, pervious concrete and other permeable pavements are great at capturing water and returning it to our continuously diminishing groundwater storage. By keeping our groundwater levels up, we not only get to continue to rely on them for our water usage, but it also keeps the ground from sinking (subsidence) and further contributing to flooding potential.
Unfortunately lately there has been more reports of devastating urban flooding in the U.S. and other parts of the world. According to this article from June of 2022, www.theguardian.com/environment/2022/jun/07/slow-water-urban-floods-drought-china-sponge-cities? :
"Globally, urban flooding has become particularly acute as the land area covered by cities worldwide has doubled since 1992. Researchers from Johns Hopkins University calculated how impervious surfaces increase flooding: every time a city increases coverage of absorbent soil with roads, pavements or car parks by 1%, runoff boosts the annual flood magnitude in nearby waterways by 3.3%."
And according to this article from way back in July 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC1257665/ :
"Paving Paradise: The Peril of Impervious Surfaces
In the United States alone, pavements and other impervious surfaces cover more than 43,000 square miles-an area nearly the size of Ohio-according to research published in the 15 June 2004 issue of Eos, the newsletter of the American Geophysical Union.
According to the nonprofit Center for Watershed Protection, as much as 65% of the total impervious cover over America’s landscape consists of streets, parking lots, and driveways.
Another big problem for urban areas is the flash flooding that can occur when heavy rains fall over a city, according to hydrometeorologist Matt Kelsch, an authority on urban flash flooding with The University Corporation for Atmospheric Research in Boulder. Since runoff from an acre of pavement is about 10-20 times greater than the runoff from an acre of grass, Kelsch says impervious surfaces can quickly trigger devastating floods that can produce a host of their own environmental health hazards."
That's a great video, I was thinking about paving my driveway using this technique on my own. However, I'm concerned it might break during winter. I live at a high latitude, and it rains a lot in winter. If some water gets trapped and freezes, the whole thing might crack. Thanks for the info though, very educational
Thankyou very very much, this will be useful for my big patio in Guanajuato 🙋🏻♀️🙏
Thank you! Human scale! This makes it useful, helpful to people in their everyday lives. Practical. The opposite is the typical ripoff 'proprietary blend in a special machine' along with a monthly sign-up for more supplies. The collective thanks and honors you! "I don't wanna be a product of my environment, I want my environment to be a product of me!"
Excellent!!! Clear, concise information!!! Thank you!!!🤔
The best explanation!
Good job! This video is exactly what i need!
I've done these in stepping tiles in my front yard. One thing is since there is a fine amount of cement, I would cover with plastic for a few days so it drys slowly.
Yes, generally covering pervious concrete with plastic as soon as it is placed is a good idea. Please check out a couple of our other videos for more ideas on how to install and cure pervious concrete:
'How to Place a Pervious Concrete Path' th-cam.com/video/y0m0yrG0ghE/w-d-xo.html
'Avoiding Raveling of Pervious Concrete' th-cam.com/video/xkkgTXbYvBI/w-d-xo.html
Very useful video, Thanks. How does this product hold up to freezing though? Wouldn't it crack?
Thank you, John! Pervious concrete holds up very well in cold climates. It has been used extensively in the northern U.S. and Canada for decades, primarily for parking lots. This topic is on my list to write an in-depth blog about since the question does come up often. There are a couple of caveats like good drainage, typically lots of drain rock, should be provided below the pervious concrete pavement. Also modified snow plows should be utilized and deicing salts not used or at least used with caution. However there is at least some evidence that pervious concrete can actually be safer, cleaner in snowy conditions since ice is less likely to build up on its surface unlike with more ordinary pavements.
Great video! What’s the best way to cure?
Interesting.
Any result videos?
I like to make a driveway using this method
A video detailing our results, with closeups and permeability shots, from a few different projects is one we have been wanting to produce for some time now. Hopefully we can get to it soon...
Hi! I am researching into flexi pave. The concrete pavement by Michelin at Yellowstone. Can you help if you have information about it?
Sand is used I. Conventional concrete to bond the cement. Will the removal of sand not substantially degrade the compressive strength of the final product?
Yes, pervious concrete can have less strength than traditional concrete. However, with the use of admixes, careful mix design and proper installation in the field the strengths of pervious concrete can be close to and similar to traditional concrete pavement, which usually achieves from 2500 psi (17.2 MPa) to 4000 psi (27.5 MPa) compressive.
Even without special admixes and a deep understanding of mix designs, pervious concrete as demonstrated in this video, typically will have way more than adequate strengths for most pedestrian and light vehicular applications. Concrete pavement most commonly fails because it cracks and becomes unsightly, which usually has little to do with its strength. One major contributor to concrete cracking is that concrete shrinks, but because pervious concrete tends to shrink considerably less than traditional concrete, it can crack less.
Perhaps the most telling example of pervious concrete's more than adequate strength, is that its most common application in the U.S. has been for parking lots. Moving forward we are demonstrating it is even possible for pervious concrete to be stronger than typical concrete pavement. We are achieving compressive strengths sometimes well over 4000 psi with our very fine pervious concrete PerkTop & PerkGrout.
Do you have a journal about this?
Could you tell what gradation of rock gives a best result ? I need to make driveway in front of my garage that will take 7000kg truck and yet I would like to have smooth surface like on your video.
For really strong pervious concrete, technically higher compressive strengths are attainable with very fine aggregates/ coarse sand. However, the permeability is significantly reduced using very fine aggregates at driveway thicknesses. So, unless you are going to utilize a two step process like with our PerkTop (perviousproducts.com/perktop/), about the finest aggregate you could use would be about 1/4" (6 mm) and possibly a little finer if the design is carefully implemented. Often asphalt plants stock this gradation of aggregate as a manufactured/ crushed rock, which would be fine.
Pervious concrete mixes using 1/4" or 3/8" aggregates will provide more than adequate strength for 7000+ kg (15,500+ lbs) trucks. They should be poured at least 5 1/2" to 6" thick over several inches of crushed, coarse aggregate and if there is a lot of this type of traffic, then thicker pavements could be necessary.
When engineers, architects and other specifiers reach out to us to see if our PerkTop is suitable for heavy vehicles like yours and fire trucks in particular, we like to reference this work put out by Timothy Lawrence and Monique Myers of the 'California Sea Grant College Program', titled 'Emergency Services and Stormwater Management':
"California allows fire engines to have a single axle weight of 23,000 pounds on the steering axle (2 tires/steering axle) and 24,000 on the drive axle. Tandem axles can be up to 48,000 pounds and tridem axles up to 54,000 pounds. All fire engine drive axles have dual tires (4 total/axle), so each
steering tire can support up to 13,500 pounds (54,000 ÷ 4).
Determining the support capability of any surface is based on the displacement of the weight over the surface area in direct contact with the vehicle tires. The contact surface area can vary by tire size, brand and inflation pressure. An example of the weight distribution of a fire engine in psi for a tire commonly found on fire engines is the Goodyear G286 12R22.5. Inflated to 90 psi, the average surface area of tire contact is 95 in
2(613 cm2). The weight displacement for each tire, if the maximum allowable load on a steering axle is 12,500 pounds or 357.14 psi, gives a 7-fold safety factor for a typical pervious concrete pavement rated at 2,500 psi."
This was an EXCELLENT video, thank you for this. One question, if you end up seeing this - how strong is this material once done? It seems to me it might be subject to cracking if it's too thin, so it would be good for some guidance on how thick I need to make my piece (and how much it might be determined by aggregate size). Thanks!
Thank you for the props! You bring up several good questions. The short answer to how strong pervious concrete is... is that it's compressive strength is typically around 2500 psi (17MPA) to 3000 psi (20 MPa), which can be a little lower than ordinary residential concrete with typical strengths ranging from 2500 psi to 4000 psi. Pervious concrete even at the lower end, at 2500 psi, is still very strong and provides over a 7-fold safety factor for supporting the weight of a firetruck!
In regards to how thick the pervious concrete should be... generally it should be at least as thick or a little thicker than ordinary concrete would be in the same application. Typically it should be at least 3 1/2" (90mm) for pedestrian areas and 5 1/2" (140mm) thick for vehicular. Soil type and thickness of the base material play a part as well. However we have successfully placed pervious concrete as thin as 2" with a couple special considerations.
If you are using your pervious concrete for some other application, not as a pavement (or perhaps as an overlay on an existing pavement), then a general rule of thumb is to make the thickness of the concrete at least 3 times the size of the aggregate. So for a 3/8" (10mm) pea gravel the thickness should be at least 1 1/8" (30mm). As was pointed out and lightly touched upon in the video, just about any size aggregate could work for making pervious concrete, however generally some loss in strength can be expected the smaller the aggregate gets starting below 1/4" (6mm) in size. Given that very fine aggregate pervious concrete is our specialty, we have developed mix designs that offset this decrease.
There are many variables that can affect the ultimate strength of pervious concrete and mitigate potential for cracking. Please keep an eye out for more videos and blogs, on our website, perviousproducts.com/ coming from us shortly that will attempt to address these questions in far greater detail than I can here.
Ryan
Wonderful info thanks! My initial project will be really light duty (exit chute for drainage tile into the yard to prevent erosion) but I would love to find more uses for this, so this is good info. Thanks again!
Can you please explain the drainage of this road?
Hello, can i know your ratio for previous concrete? Thank you
I think this is a good solution to resurfacing a walkway. Install bricks on the edge of the sidewalk two bricks tall and use an epoxy adhesive to make the bricks stick to the sidewalk and the next brick. Then use an acid etching concrete cleaner to prep surface of concrete. And also an adhesion promotor rolled on lightly with a roller and cut in the edges with a cheap brush. Directly after it dries use this mix to pour a 1-2 inch layer on top of the sidewalk and the bricks on the side will act as a border and a wall too for mulch and grass. The water will drain down and out from in between the bricks. Only use one brick if you don't want a tall edge and pour the mix to the height of the 1st brick evenly without getting a bunch of stuff on the brick but you can wash it off with a brass wire brush and hose easily just try not to wet the wet concrete mix.
This is my solution to a sidewalk with flat spots. I should either resurface the sidewalk first before this mix goes on top and make a grade towards the side to let water flow off the edge of the sidewalk in between the bricks and maybe use a concrete blade on my grinder to cut a few squares or circles and install basic plastic drain covers as the stuff under the sidewalk is all sand. I live on the beach and all we have is sand here and we are only 6 feet above the water table. But oh well. I am going to just wing it. I might cut a few circles and install some drains that connect to a small diy French drain underneath the mulch bed on the side of the sidewalk or install a few catch basins and use this around the housing and leave room to put the drain covers on but we will see how far my motivation goes that day. Lol
Will frost cause any problems with this product? We don't get very cold temperatures here -5 Celsius is about the limit but 0 to -1 more commonly.
Pervious concrete holds up very well in cold climates. It has been used extensively in the northern U.S. and Canada for decades, primarily for parking lots. This topic is on my list to write an in-depth blog about since the question does come up often. There are a couple of caveats like good drainage, typically lots of drain rock, should be provided below the pervious concrete pavement. Also modified snow plows should be utilized and deicing salts not used or at least used with caution. However there is at least some evidence that pervious concrete can actually be safer, cleaner in snowy conditions since ice is less likely to build up on its surface unlike with more ordinary pavements.
We're doing a school project with earth force this really helped thanks
Had a great time today in Moss Beach.
Hey Steve, thanks for checking out our latest PerkTop pervious concrete installation! A couple of years ago we also installed a driveway around the corner at: 670 Stetson St. Moss Beach, CA 94038. And just down the road a bit a couple of months ago we installed a PerkTop driveway in tan color at: 608 Ruisseau Francais Ave. Half Moon Bay, CA 94019.
A little further afield, we installed pervious concrete for significant portions of the large parking lot at the new Cadillac dealership in Colma, CA. Upcoming, at the start of the new year we will begin installing 57,000 square feet of pervious concrete for large portions of the new 'Veterans Memorial Parking Lot' in San Rafael, CA.
We have installed countless other PerkTop projects in the San Francisco/ San Jose Bay Area. If you would like to check out any of those, let me know and I can provide a list accordingly. Thank you, Ryan
can we replace cement and use melted plastic and stone removing stand and cement
Curios about the effect of adding a mesh or loose fibres (metal or synthetic)
Adding fibers and/ or mesh to pervious concrete can be beneficial. Just about any type of fiber or synthetic mesh is compatible, except notably, do not use metal in pervious concrete. Metal, whether it is rebar, wire mesh or steel fibers (except stainless) will get exposed to water in pervious concrete and rust, corrode and expand damaging the concrete and becoming ineffective. Basalt rebar, fiberglass and other composite or coated rebar can be used in pervious concrete. We have also used anodized aluminum for doweling with success so far.
In regards to the effect that adding fibers or mesh will have on pervious concrete it is difficult to quantify. In general one would want to measure for a higher tensile ductility, but since there aren't even any ASTM or other approved compression strength tests for pervious concrete, any tests will need to be set up and documented very carefully. Anecdotally, I will say pervious concrete samples that we crush for physical strength tests that have fibers notably stay together much better past failure and do not tend to 'explode' as much as samples without fibers. So the right type, combination and dosage of fibers should translate into a pavement that does not crack as much or as noticeably.
Seems like a lot of work? Can these pavers be purchased somewhere?
They cannot yet, but we do hope to be able to provide them shortly.
Does it heat up much?
What additional considerations for Driveways? I.e. for vehicular traffic. Can you use reinforcing mesh?
Generally it is a good idea to make pervious concrete a little thicker than ordinary concrete. So for vehicular use often 5.5" to 6" (14 to 15 cm) is adequate. Making it thicker helps to offset not being able to use reinforcing mesh. Since wire mesh or rebar would corrode quickly due to all the moisture moving through the concrete it is not recommended for pervious concrete unless it is coated or treated. Alternatively, non-metal fibers can be used for varying amounts of reinforcing.
For more discussion of how thick to make pervious concrete for various applications:
perviousproducts.com/thick-make-pervious-concrete/
Thank you for your response, I can't believe I didn't recognize the corrosion aspect my self :). Yes I have heard of the fiber additive. Anyway I'll check the link.@@perviousproducts6648
Have you tried making hollow blocks out of these?
We have not tried making hollow blocks out of pervious concrete yet. I assume with vibration it could be done.
Thank you so much! This was incredible helpful!
Do you think I can use rock bigger than 3/8 "? Suppose 3/4 "
Yes, one can make pervious concrete with just about any size rock. The downsides to using coarser 3/4" (19 mm), or similar large aggregate, are that it can be more difficult to mix and finish, it will generally require more cement to achieve similar strengths, and the finished product is quite rough looking.
What is the highest psi per square foot that has been most successful?
Though there are no standardized ASTM or other compressive strength tests for Pervious Concrete, typically when it is installed properly in the field one would expect it to achieve around 2500 to 3000 psi (17 to 21 MPa) compressive strength. This is on the lower end of more traditional concrete, but more than adequate for most vehicular and other applications. However, if the pervious concrete mix was designed very optimally, 4000 psi (27.5 MPa) compressive strengths can be attained. Even higher strengths are attainable with Pervious Concrete utilizing very fine aggregates, but this tends to significantly reduce its permeability at much thickness.
When applying the product can it compact with vibration?
Pervious concrete can be installed using compaction with vibration. However one needs to be careful using this combination as it can very easily lead to over compaction and sealing up of the pervious concrete. Alternately, if the compaction with vibration is delivered a little too late to the fresh placed pervious concrete, it can damage it and lead to raveling (loose rock on the surface). Therefore the timing and compactive force need to be precisely and constantly monitored based on the specific pervious concrete mix and changing site conditions. All that being said, compacted and vibrated pervious concrete can produce the highest compressive strengths.
@@perviousproducts6648. Thank you.
'cement powder'? is that whats called portland, in texas?
Yes, typically the cement used in pervious concrete is 'portland cement'. It can be any of the types of portland cement used in the U.S., Types I, II, III & V. However, other types of cement can also be used successfully in in pervious concrete. For instance, our PerkGrout product utilizes CSA (calcium sulfoaluminate) cement or 'rapid set'. The primary reason for its usage in this application is due to CSA cement's low shrinkage and therefore reduced cracking potential.
Can be used in high temperature area ?..
Like 50 degree Celiac's?
Pervious concrete can be trickier to place in high temperatures, but once installed high temperatures are not a problem at all. Even in full, intense sun where pavement temperatures can exceed 75 degrees Celcius (170 degrees Fahrenheit) pervious concrete, just like ordinary concrete will do fine.
For tips on how to place pervious concrete in high temperatures, check out a couple of our other videos:
th-cam.com/video/y0m0yrG0ghE/w-d-xo.html 'How to Place a Pervious Concrete Path'
th-cam.com/video/xkkgTXbYvBI/w-d-xo.html 'Avoiding Raveling of Pervious Concrete'
Might use this for a base for pervious bound resin finish.
Yes, pervious concrete can be used as a base for many products, including resin bound.
Sir can we use the rocks that are used for road and building construction 👌👌
Almost any rocks/ aggregate can be used successfully in pervious concrete. If the aggregate is dirty, dusty or has a lot of fines in it, this will tend to reduce the compressive strength of the pervious concrete, but not typically by an egregious or detrimental amount.
If the aggregate is too well-graded, has too broad of a gradation, this can reduce the pervious concrete's permeability. Or using well-graded aggregate in pervious concrete can require less cement to get the desired permeability, thus reducing its compressive strength.
We like to use clean, gap or narrow gradation aggregate for most of our pervious concrete in large part because we feel we can get more consistent and reliable results.
Can the same be used as road pavement with required strength as desirable to be M40 / M30 concrete or so ?
While it is possible to achieve those strengths in the lab, I am not aware of pervious concrete achieving compressive strengths of 30 MPa and higher in the field, on installations. It can certainly be used on lower volume roads, and with proper mix design and careful quality control while placing, pervious concrete can consistently achieve 25 to 28 MPa compressive strength. It is also possible to achieve flexural strengths greater than 4 MPa with pervious concrete, so this test could possibly be used instead of compressive. And finally pervious concrete pavement can be poured thicker to also achieve a higher overall 'Structual Number'.
Does it allow light?
Though pervious concrete allows air and water through it does not allow light. It is not translucent in any way.
@@perviousproducts6648 Thank you so much
Excellent video. Thank you!
Excellent video ando very useful information! Thanks for sharing. Greentings from Mexico.
is there any code which should be followed to obtain the particular ratio and should be nominal porosity of pervious concrete?
Yes, the technical way to determine the ingredients of a pervious concrete mix:
1. Find the void content of the aggregate that will be used:
voids, % = 100 ((S x W) - M) / (S x W)
M = bulk density of aggregate lbs / cuft - dry rodded
S = dry bulk specific gravity
W = density of water (62.3 lbs/cuft)
2. Use the NRMCA pervious concrete mixture formula found at the bottom of this page:
www.perviouspavement.org/materials.html
Currently there are not any standards set for the minimum permeability of pervious concrete, that I am aware of. Traditional 3/8" (9.5mm) aggregate pervious concrete mixes, with around 20% voids, often drain in excess of 600"/hour (4.2mm/second)! Unless one is using the pervious concrete as a catch basin (not recommended), this degree of permeability is far in excess of what is actually needed to absorb even the most intense rain event.
Strength is at least somewhat inversely proportional to permeability in pervious concrete, meaning that generally the lower the permeability, the higher the strength for any given aggregate. Since we often prefer to design our pervious concrete mixes using finer, 1/8" (3mm) and smaller, aggregate (primarily for aesthetic reasons) and these finer mixes can be weaker (though we use admixes to offset this), we like to achieve just enough permeability to even further maximize our strengths. 'Just enough' permeability for pervious concrete we feel like is over 200"/hr (1.4mm/sec), because it still looks impressive when some water is dumped on it. No, it won't immediately absorb the full contents of a ready mix truck filled with water, but it will quickly drink a bottle of water and more importantly infiltrate any type of rain event that may come along.
Nice topic how to get PERVIOUS CONCRETE consistong of cement, water and coarse aggregates. Regarding the open structure of pervious concrete, air and water can penetrate into the subsoil though voids existing with in the concrete. This kind of concrete has various physical and mechanical properties but also pasive green structural site for contributing wat is significant. PLANTY GOOD STRUCTURES we can do with pervious concrete.
My question is what is the max compressive strength and the right water cement ratio
Though there are no standardized ASTM or other compressive strength tests for Pervious Concrete, typically when it is installed properly in the field one would expect it to achieve around 2500 to 3000 psi (17 to 21 MPa) compressive strength. This is on the lower end of more traditional concrete, but more than adequate for most vehicular and other applications. However, if the pervious concrete mix was designed very optimally, 4000 psi (27.5 MPa) compressive strengths can be attained. Even higher strengths, 5000+ psi (34+ MPa) are attainable with Pervious Concrete utilizing very fine aggregates, but this tends to significantly reduce its permeability at much thickness.
Determining a particular Pervious Concrete's proper water cement ratio (w/c) is tricky and is therefore we feel best finalized by visual confirmation using the descriptions in the video. The main reason for this is the amount of moisture in/ on the aggregate that is used. Inevitably this amount will vary within a pile of aggregate, throughout the course of a day, and from one day to the next. Just a small change in this water in the aggregate pile will make a significant difference in the water needed for the mix. For instance, the amount of water in an aggregate pile following a rain event can sometimes provide practically all the water that is needed for that mix.
The types and amounts of admix used in the Pervious Concrete mix design will also have a huge impact on the water cement ratio. Because of this, we have designed mixes with below a .2 and above a .5 w/c, however most often we end up being around a .35 w/c. But please take the time to really dial in your own particular mix's optimal water cement ratio and keep an eye on your aggregate's water content!
Thanks for posting this video. Simple easy information.
what about in winter. Wouldn't ice destroy it?
Only if you do not have good drainage and water gets trapped in the concrete... other vids show about a 2 ft bed of large aggregate (in freezing climates)...
Can be use in heavy traffic area?
Yes, pervious concrete can be used in heavy traffic areas, even for large truck and bus use. For more info on this, check out our blog:
perviousproducts.com/thick-make-pervious-concrete/
how about porous asphalt?
Fantastic explanation.
could anyone kindly tell the amount of materials I need for a school project?
can you please tell me what are test to conducted on this type of concrete and mix ratio???
There are four (4) ASTM tests specifically designed for pervious (permeable, porous, thirsty) concrete:
ASTM C1701 Standard Test Method for Infiltration Rate of In Place Pervious Concrete
ASTM C1688 Standard Test Method for Density and Void Content of Freshly Mixed Pervious Concrete
ASTM C1747 Standard Test Method for Determining Potential Resistance to Degradation of Pervious Concrete by Impact and Abrasion
ASTM C1754 Standard Test Method for Density and Void Content of Hardened Pervious Concrete
Currently there is not an ASTM test directly related to the strength of pervious concrete. Also even though there is a test, C1701, for measuring the permeability of pervious concrete, there is no consensus of what that rate should be.
One can test pervious concrete using cylinder and cube molds for compressive, flexural, tensile strengths just like with ordinary concrete. The trick is documenting how the lab tests will accurately reflect the field results. There are so many factors that have an out-sized impact on the field results of pervious concrete, like weather, slight changes in the aggregate gradation or water, degree of compaction, et al.
Determining the exact mix ratio for pervious concrete can be a challenge and varies depending on the aggregate used, weather and other onsite factors and what characteristics the installer and/or customer desire. The best approach can be to take our basic formula outlined in the video and start making small samples using your desired aggregate, carefully documenting the process and recording the results. We like to start this process by comparing permeabilities of various mix ratios.
Sir and the cement can we use any type of cement🕰🕰🕰
Most Portland Cement are compatible with pervious concrete. All the different Portland Types seem to have the same attributes in pervious concrete as they do in ordinary concrete with no discernible deleterious results.
The one factor to be wary of however is ASR (alkali-silica-reactivity) or other issues with the aggregate chosen.
Fly ash, slag, silica fume and other pozzolans also seem to be compatible with pervious concrete in approximately the same substitution rates as they are in ordinary concrete.
CSA (Calcium Sulfoaluminate) cements and no doubt, many others are also able to be used in pervious concrete.
What weight can it bear? And it's life?
Pervious concrete can be designed to support about any weight. Its most common application in the U.S. has been on parking lots. If designed and installed properly pervious concrete can also be used for higher and heavier traffic areas like bus stops, semi truck parking and even highways. We go a little deeper into this topic on our blog:
perviousproducts.com/thick-make-pervious-concrete/
Pervious concrete will last as long or longer than ordinary concrete, 20 plus years. Pervious concrete has the potential of lasting longer because it tends to shrink less, therefore it generally cracks less than ordinary concrete.
Thank you so much! I didn't found this explications in my language.
But where does the water go? Is there no drainage under the concrete? If it just lies under the slab, and it freezes, you have a heaving problem.
As I mentioned in an earlier post, this important topic, of pervious concrete in cold climates, requires an in-depth blog or even its own video. Typically several inches of open drain rock are used for the base and drainage of pervious concrete. To see how deep this rock layer should be, check out our blog perviousproducts.com/pervious-concrete-base-material-depth/.
Suffice it to say, in heavy freeze-thaw environments this drain rock layer should be deep enough to accommodate any rain and/or melted snow. The bottom line is pervious concrete has been installed all across the USA and Canada for over 30 years now with very good results, including in extremely cold climates.
@@perviousproducts6648 There are probably some areas where this type of pavement would not be advisable, or would need a modified base. For instance, where I live, a driveway might freeze 5 feet deep since it is kept clear of snow (which would otherwise act as insulation) and since the weight of traffic has a tendency to drive the frost deeper than usual. Also, the soil is impervious clay which holds water near the surface thruout the winter, effectively bringing the water table up to within 6 inches of the surface. Thus roads and driveways normally heave up several inches during the course of the winter. A typical open-graded base would fill with water and freeze, then the water would freeze within the pavement itself, possibly causing it to break apart. The only way I can think of which might work would be to build a very thick open-graded base, several feet deep, which would be placed entirely above the ground level and thus above the high water level, providing enough room for water to dissipate before it freezes. But even then I wonder if it would work.
@@ethanlamoureux5306 The other thing one could do in this situation is to add perforated drain pipes in the gravel base to redirect excess water away from the pavement. It is also recommended to use air-entrainment and/or other modified mixes in freeze-thaw climates. Again pervious concrete has performed well in heavy freeze thaw and there are even potentially some advantages to it over ordinary pavement. Light amounts of snow can dissipate faster, ice doesn't tend to accumulate on the surface making for safer pavements and less need for deicing salts.
Can we use natural stone gravel
To be on the safe side it is typically best to use aggregates that already have a history of being used in concrete. Sometimes aggregates can have deleterious effects and you'll want to have a minimum hardness. So I wouldn't use a soft stone, like sandstone, for the gravel.
Could you share us the water-cement ratio to get the correct amount of water?
There are many factors that go into determining the correct w/c (water to cement ratio) for a particular pervious concrete project: the type and size of the aggregate; timing between when it is mixed and placed; the quantities and types of admixes that are used (if any); and even the temperature and humidity make a difference, the warmer and drier it becomes, the slightly more mix water will be needed. It is best to become familiar with your specific mix design, documenting the amount of water needed for a particular amount of cement, to achieve the correct consistency when placed, knowing what too-dry, too-wet and just-right look like.
Being familiar with how the consistency of the pervious concrete should look will help overcome the biggest variable for determining the amount of water, which is the moisture content of the aggregate itself. Most w/c recommendations are given off of ssd (saturated surface dry) aggregate, where the minimal aggregate pours are filled with water, but the surface is not visibly wet. This is a mythically impossible condition to achieve for anywhere but the lab. In real life (field conditions) the aggregate is going to vary considerably in wetness, even within the same pile, and the slightest changes in moisture make a big difference in the final consistency of the pervious concrete mix.
Ao aplicar o produto pode compactar com vibração?
Bom dia,pode passar veículo
Bro please tell how to made the concrete sample because our project is same as you told
Please tell me what the components are required and how to mix them
Please reply bro
Which strength occured in the material
The short answer to how strong pervious concrete is... is that it's compressive strength is typically around 2500 psi (17MPA) to 3000 psi (20 MPa), which can be a little lower than ordinary residential concrete with typical strengths ranging from 2500 psi to 4000 psi (28MPa). Pervious concrete even at the lower end, at 2500 psi, is still very strong and provides over a 7-fold safety factor for supporting the weight of a firetruck!
However there currently are not any ASTM or other certified tests for determining the compressive strength of pervious concrete. I believe this is so, in large part because there are just too many variables in the mixing and placing of pervious concrete. Unlike ordinary concrete, just because a certain result is obtained for a specific pervious concrete mix design in the lab does not in any way guarantee the same result in the field. Slight changes in the water content, the weather, timing of the placement and compaction differences are all factors that will significantly influence the final strength of pervious concrete.
How do mix design for pervious concrete sir.
Where to find pea gravel
Thank You Helped a Lot
Can pervious concrete be made with perlite as the aggregate instead of solid rocks?
Pervious concrete can be made from lighter weight material, but using perlite will not produce a very strong mix. It probably will not be strong enough even to walk on, but might be suitable for some type of pottery or other decorative applications. Some expanded shale/ clay can make suitable pervious concrete pavement.
I found green ant builder create this type of product using plastic waste for mixing material. I really love the idea, I want to bring this idea to my cummunity, but they charge this tech with high price, can you please teach me how to make previous concrete to use for paving road? I would love to discuss this idea
The little bit we experimented with incorporating plastic waste in our pervious concrete, it did not yield promising results. It may be possible to substitute a portion of the aggregate with recycled plastic in pervious concrete without negatively impacting the strength too much. However, since pervious concrete needs to be optimized to be suitable for road traffic, incorporating plastic waste into it would probably bring us further from that goal of using it in high traffic applications.
@@perviousproducts6648 by far greenant product only suitable for side walk or maybe for some park or garden, they also make a interlocking brick with slightly different material mix for home wall, this is really interisting for me
Sir can you please answer my questions
I was wondering if this type of road can be made of plastic waste and e waste as my final year project 😅
Some plastic could be incorporated into pervious concrete, but it would need to be kept to a somewhat minimal amount. Plastic in too large quantities will lower the strength of the concrete.
Do you suggest some topics for final year project
Can you plzz.. tell the materials that are been used
Didn't you watch the video? Everything you need is there
very good guide.
How to increase strength ?
There can be many ways to increase the strength of pervious concrete. However before too much effort is invested in optimizing the strength, one needs to ensure the quality control for the entire installation process is really dialed in. Most of the variance in pervious concrete strength being placed today is due to to inconsistent installation, so much of it is not reaching its optimum/ designed-for strength to begin with.
Once one has a firm understanding of their current process and mix ingredients, including the aggregate characteristics and its relationship to binder and water ratios, then one can begin further optimizing the strength of the pervious concrete mix. Utilization of some of the same principles of achieving high strength concrete can result in greater compressive strengths in pervious concrete. To increase flexural strength or the modulus of rupture, arguably the most important factor for a pavement, addition of acrylic and/ or certain fibers can yield good results.
Why don't u use fine aggregate. ?
One can add a small amount of fine aggregate (sand) to pervious concrete, but obviously the risk is if too much is added and it then becomes impervious. Controlled amounts of fine aggregate are sometimes added to pervious concrete, depending on the coarse aggregate that is used and if a little higher strength or resistance to freeze-thaw damage is desired.
On the other hand we usually make our pervious concrete or at least our pervious concrete topping out of all fine aggregate. By using the coarse end of fine aggregate (sand) we make a very smooth, attractive pervious concrete.
The best thing is to test different aggregates and combinations with varying amounts of cement and see what works best for your particular application. Compare permeabilities, strengths and aesthetics. Have fun!
Really nice how to. I hope I will try making one for fun.
Great tutorial...thks
no sand??
Taking the sand, fine aggregate, out of ordinary concrete is generally what produces pervious concrete. However, it is possible to add very small, controlled amounts of sand back to the pervious concrete mix. This may be advantageous to reduce the permeability somewhat and gain strength and durability in mixes containing particularly large coarse aggregate or possessing 'too much' voids.
How to arrive material quantity for concrete
Excellent!
This material will be good for absorbing rain
Great Job !!
Thank so much for this video
Thank you for participating!
Wat is the setting time
The 'setting time' is similar to ordinary concrete, typically an hour plus for initial set. However the 'working time', the time one actually has to place and finish, for pervious concrete is much less than ordinary concrete. It can be as low as a few minutes in less than ideal conditions. Please check out a couple of our other videos for an in-depth answer to this: th-cam.com/video/y0m0yrG0ghE/w-d-xo.html ("How to Place a Pervious Concrete Path) and th-cam.com/video/xkkgTXbYvBI/w-d-xo.html ("Avoiding Raveling of Pervious Concrete).
@@perviousproducts6648 tq so much
I've tried it 3 times but It doesn't work
So helpful, great video, make more videos like this one
Thanks ❤
Too good sir.
Bangladesh need this for flood management
There are a lot of areas that could benefit from using pervious concrete to minimize occurrence of flooding. It is helpful in two ways. To begin with pervious concrete slows down or eliminates entirely rainwater from running off the pavement. Then the water that is absorbed by the pervious concrete slowly makes its way through the subsoil and recharges the groundwater. Keeping the groundwater, which is often relied on for domestic use, full is important because if it drops too low subsidence can occur. Subsidence is when the ground actually sinks and lower ground of course is more prone to flooding. Subsidence is a permanent, irreversible process and if too much occurs the ground can become impermeable and unable to absorb more groundwater.
Large portions of the city of San Jose, California in the U.S. have sunk 13 feet (4 meters). Recently Jakarta was named the fastest sinking city in the world, www.bbc.com/news/world-asia-44636934, with parts of it sinking as much as 25 cm a year!
Have fun after winter ...
Pervious concrete when installed correctly performs well in very harsh freeze-thaw environments. Please see earlier comments on this thread in this regard.
excelente gracias
self healing concrete is good thanks
Excellent well made video
Thanks for this
Thank you sir
why ?
gracias !!!!!!!