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Build a Stronger Foundation for Infrastructure Projects with 3D Soil Confinement

It’s no secret that America’s infrastructure is desperately in need of investment. The American Society of Civil Engineers (ASCE) gave the country’s infrastructure an overall grade of D-plus in its 2017 Infrastructure Report Card—dangerously close to an outright failing grade. The ASCE estimates that the U.S. will need to spend nearly $4.5 trillion by 2025 to fix the country’s roads, bridges, dams, and other infrastructure.

Our nation’s roads and bridges—commonly referred to as the “backbone” of the U.S. transportation system—received grades of D and C-plus, respectively. These transportation systems are deteriorating due to advancing age, increasing use, and inadequate funding. This degradation leads to a significant cost to users in terms of time, money, and safety.

There are over 4 million miles of road in the United States, and the cost to maintain these roadways can vary greatly by state. Several factors determine maintenance costs, including the type of pavement surface, its current condition, its geographical location, average precipitation, number of annual freeze/thaw cycles, and frequency of use.

Three-Dimensional Geocells Provide Solutions to Aging Infrastructure

The long-term performance of infrastructure construction projects depends on the strength of the underlying soil. Through an interconnected honeycomb-like network, 3D geocells confine and stabilize soils that would otherwise be unstable under loading. The GEOWEB® 3D Soil Stabilization System is the industry’s most complete geocell system, designed with fully engineered components to withstand the most challenging site conditions. These components are built for strength, durability, speed of installation, and long-term performance.

Extend Pavement Life with the GEOWEB® System

When incorporated into the base layer under asphalt or concrete, the GEOWEB® 3D Soil Stabilization System dramatically reduces the occurrence of rutting, potholes, and pavement degradation. The GEOWEB® system does this by performing as a semi-rigid mattress and distributing loads evenly over soft subbase soils, significantly reducing deflection and settlement.

Three-dimensional soil confinement delivers higher performance and offers adaptability with varying fill materials, subgrades, and loading stresses when compared to two-dimensional geosynthetic solutions. The positive effect on the pavement base layer results in up to a 30% reduction in required pavement thickness and an extended pavement life with lower maintenance requirements and costs.

 

Build Safer, Lower-Maintenance Road Shoulders

Road shoulders play a vital role in the performance of roads and highways. They provide additional structural support for the roadway and a safe area for drivers and emergency responders to maneuver in the event of an emergency. The GEOWEB® system creates stable shoulders that reduce typical maintenance by up to 3 times and protect sealed pavement from deterioration and edge breaks. The GEOWEB® road shoulders can be designed with permeable aggregate or engineered topsoil/aggregate infill to facilitate vegetation.

Stabilize the Surface Around Bridge Abutments

Using the GEOWEB® system, you can design and construct bridge embankments with topsoil/vegetation, aggregate, or hard-armor concrete infills. The flexible nature of the GEOWEB® panels allows it to easily contour to the slope face and around obstacles such as piles and abutments. The GEOWEB® system prevents erosion around the abutments, which reduces lifetime maintenance costs.

Whether it’s a new project or repair work, you can build stronger, lower-maintenance roads and roadway structures with the GEOWEB® system—and with your own road and highway crews.

Presto Geosystems Offers Free Design Support and Tools

The engineering team at Presto Geosystems works closely with civil engineers, offering free project evaluation services and on-site support for roads, embankment or erosion control projects.

Keep Projects Moving Forward With Our Free Design Tools and Project Evaluations

There’s no denying that life looks a lot different than it did a month or two ago. Most of us have been affected by COVID-19 in some way. While the degree to which we are feeling these effects varies by person, population, industry, etc., this situation has changed the way we all live and do business.

Those who are able to work remotely are adjusting to a new normal. With schools closed indefinitely, many of us are now simultaneously trying to manage workloads while homeschooling and meal prepping. People in many industries are working tirelessly on the frontlines ensuring that we have access to essential goods and services, and we are incredibly thankful for them.

Learn From Home and Earn PDH Credit

With shelter-in-place orders still in effect for many regions, we will continue to evaluate how we can better serve our partners in the engineering and construction industries. Over the past month, we have increased our offerings of live webcasts to stay connected and provide colleagues and customers with a direct line to our engineering team. We will continue to offer these webcasts, as well as customized virtual technical presentations for your engineering staff.

Free Design Support and Tools

As we begin to see a shift from “relief” to “recovery,” we anticipate a surge of new construction projects, and some industry experts have even predicted a forthcoming “construction tsunami.” It is imperative that our industry remains prepared to respond to these opportunities when the time comes. We’re here to help.

The team at Presto Geosystems is here to provide project engineering support from the preliminary stages through installation and follow-up. Use our free online tools to keep your projects moving forward. There is absolutely zero risk and zero cost associated with our online tools.

We are committed to delivering quality products and services when you need them!

Presto Geosystems: Safe, Open, and Ready to Help

Like all of you, Presto Geosystems is closely monitoring COVID-19 events as they unfold, and we will continue to keep the best interest of our employees, partners and customers at the forefront of our operations. While the locations from which we are working and our methods of communication may have changed, our commitment to you has not. Presto Geosystems is still open for business, fulfilling orders and keeping your construction projects moving forward.

With the recent travel restrictions, our team of design engineers, business managers and partners are happy to meet with you virtually to discuss your project needs. If you are working from your home office—we’d love to meet your kids or dogs!

Keep your construction projects on schedule by utilizing our online design/installation tools, customized design support and free online learning courses.

We are committed to delivering quality products and services when you need them!

FHWA Repeals its Proprietary Product Rule, Allows Geosystems’ Products to be Specified

By: William G. Handlos, P.E.

Design engineers received good news on September 23, 2019, when the Federal Highway Administration repealed 23 CFR 635.411(a)-(e).

Colloquially known as the “Proprietary Product Rule”, the long-standing provision made it difficult to use patented or proprietary products or technologies in federally funded projects, unless they first received a seldom-granted Public Interest Finding or classified the project as experimental.

Specialty engineered and innovative systems, such as the GEOWEB® soil stabilization (geocells) lineup of products have at times been difficult to specify because there is simply nothing quite like it in the marketplace. While other geocell manufacturers exist, the Geosystems products have patented innovations making it unique in the products’ ability to perform far better than other “or equal” systems.

Now, engineers will no longer be constrained to the lowest common denominator offerings from the marketplace and instead can use technically advanced materials that reduce costs, speed construction and save money.

According to Federal Highway Administrator Nicole R. Nason, “This final rule promotes innovation by empowering states to choose which state-of-the-art materials, tools, and products best meet their needs for the construction and upkeep of America’s transportation infrastructure.”

 

 

 


GEOWEB® — Most Complete Multicomponent Geocellular Confinement System

For information related to the design advantages offered by GEOWEB® geocells, visit www.prestogeo.com.

The Integration of Pervious & Impervious Pavements to Address Green Infrastructure Needs

Written by: Samantha Justice, P.E.

Green infrastructure incentive programs have become commonplace for new construction and redevelopment regulations. Five of the most common incentives include:

  • Development incentives such as expedited permitting, decreased fees, zoning upgrades and stormwater requirement reductions.
  • Grants
  • Rebates and installation financing
  • Awards and recognition programs
  • Stormwater fee discounts

A subset of green infrastructure, stormwater management usually includes the consideration of pervious and porous pavements. Traditional asphalt and concrete parking lot surfaces create significant stormwater runoff, and in many municipalities, cannot be used in expansion or new build situations.

When the paved area is constructed completely with a porous pavement, stormwater concerns are greatly reduced. Depending upon the choice, pavements that return rainwater to the aquifer not only nearly eliminate stormwater runoff – they also reduce sheet flow and point load erosion problems at the pavement edges, and reduce need for additional stormwater infrastructure to convey the water away from the area. Porous pavement systems can be directly integrated with asphalt and concrete surfaces to reduce such failures and reduce or eliminate the need for stormwater conveyance channels, pipes, and swales. As a result, downstream stormwater pipe systems see less silt and less water which requires less maintenance and less capital expenditure for upsizing stormwater pipes.

Increase Parking Capacity

Expanding parking areas with porous pavement can have a neutral effect upon the existing stormwater loading or in some cases can even decrease existing loading.

  • In cases where existing parking areas drain to internal inlets, additions self drain, but seldom offer any benefit to existing hard surfaces.
  • In cases where parking areas sheet drain in the direction of the parking capacity addition, the new porous surface can go beyond self-draining and can cut off sheet flow and absorb hard surface runoff. Of course, one has to be careful not to overload the new porous system with sediment.

 

 

 

 

 

 

 

 

 

Integrating Permeable with Impervious Pavements

Not all new build parking lots need to be 100% porous. A mix of pervious and impervious surfaces can solve both stormwater concerns and heavy traffic loading expectations. Using asphalt or concrete surfaces in the drive lanes of parking lots alleviates stresses on the system from repetitive passes from vehicles, and ensures that all types of vehicles can use the lot. Joined to these drive lanes can be adjacent porous parking stalls, controlling stormwater runoff and eliminating the need for inlets and conveyance systems. While permeable infill promotes fast infiltration, the base depth may be designed to suit the stormwater needs of the site–allowing for storage and natural percolation.

 

 

 

 

 

 

Semi-rigid resin based porous pavement units may be filled with either aggregate or topsoil, allowing for customization of parking lots for aesthetic appeal while considering intensity and frequency of use. The permeable paver units are easily cut to seamlessly align with hard pavements (permeable pavers, asphalt, concrete), even along curved lines. Impervious surfaces can be painted for centerlines and turning lanes. Porous pavement units offer delineators, allowing parking stall lines and other separation markers. Parking stops and signs can be easily installed over porous pavement units, so there are no limitations when it comes to fully outfitting parking areas for a project’s needs.

The Benefits of Porous Pavements in Pavement Design

Whether porous pavements are included in all or part of a green infrastructure pavement project, the benefits they offer for reducing runoff and stormwater infrastructure size/need, protecting watersheds, and reducing cost are significant.

Presto Geosystems offers the GEOBLOCK® grass and GEOPAVE® gravel porous pavement systems to help control stormwater, meet load requirements and suit landscape plans.

See our Myth Busters Blog Series for how the units eliminate typical concerns about using porous pavements.

For more information on porous pavements, visit our web page: Porous Pavements.

    

 

Are you using the right construction access mat for the job?

By: William G. Handlos, P.E.

Research shows that GEOTERRA® and GEOTERRA® GTO structural mats provide a ground-surface reinforcement layer to support heavy loads over soft subgrades. More cost-effective than other reinforcement mat systems, the GEOTERRA mats can be utilized for either temporary or permanent applications and are reusable. Offering high crush and flexural strength, the GEOTERRA mats have demonstrated the ability to handle the forces from some of the heaviest wheeled and tracked vehicles under severe conditions.

Scope of Test:

Performance testing of the GEOTERRA and GEOTERRA GTO mat systems was conducted at the University of Kansas Geotechnical Laboratory over weak to intermediate subgrades with CBR values ranging from 1% to 4%. A total of twelve tests were conducted to identify threshold and limit conditions, to create a data-set for modeling, and to determine the equivalent crushed aggregate base.

Testing Procedure:

All of the test sections were subjected to 40 kN (9 kip) cyclic loading on a 300 mm (12 in) diameter plate. Earth pressure cells were placed over of the subgrade to measure vertical interface stress distribution. Loading plate displacements were measured by the displacement transducer inside the actuator.

Test Observations:

The following conclusions were determined for the GEOTERRA and GEOTERRA GTO Structural Mat Systems:

  • GEOTERRA mats provide additional support for weak to intermediate subgrade subjected to cyclic loadings by reducing permanent deformations and rate of increase in the permanent deformation of the subgrade.
  • GEOTERRA GTO mats was most effective in cases of larger permanent displacement.
  • The vertical interface stresses between the mat and the subgrade close to the center of the loading plate decreased with an increase of loading cycles. This result is different from that for the aggregate base over the subgrade, in which the vertical interface stresses close to the center increased with the number of loading cycles.
  • Both GEOTERRA mat systems performed similarly to the 12-inch (300 mm) crushed aggregate base over 2% and 4% CBR subgrades.

Test Conclusions:

  • Both GEOTERRA and GEOTERRA GTO mats decreased interface stresses at the load point, which reduces soil movement and ultimately leads to a significant reduction in rutting.
  • Although subjected to rigorous point load testing, the GEOTERRA mats received no significant damage.
  • The testing data proved that the GEOTERRA mat system performed similarly to 12 inches (300 mm) of crushed aggregate base in controlling permanent deformations over 2% and 4% CBR subgrades, with the GEOTERRA GTO mat system performing similarly, but slightly better.

Modular polyethylene construction access mats are lightweight, easy to place without the need for heavy construction equipment, and particularly useful when speed of placement and removal are a factor or when space is at a premium.

To get more information about GEOTERRA mats, go to www.prestogeo.com/products/construction-mats/geoterra-construction-mats/.

Porous Pavements Myth Busters: Cost

Written By: William G Handlos, P.E.

Does a porous pavement solution cost more?

Porous pavements actually are less expensive to install than impervious concrete or asphalt when total project costs are considered. When evaluating parking lot construction costs for porous vs. impervious alternatives, the following cost “buckets” must be considered.


Traditional pavements such as bituminous asphalt or Portland cement concrete enjoy low cost and ubiquitous installation contractors. This may lead one to think that choosing a porous pavement would lead to higher overall project costs… But that is a myth.

 

Most everything else about traditional parking lot construction is far more expensive than the porous pavement alternative. Traditional hard-surface pavements require inlet structures, castings and covers for inlets and manholes, underground pipe, outfall structures, and detention ponds.

Costs & Maintenance of Stormwater Ponds

Detention ponds have three major cost drivers. Land costs to locate a pond can vary wildly depending upon commercial real estate values, but it is not unusual for land to be upwards of $250,000/acre even in small markets. But the impact of the land utilized for detention ponds doesn’t end there. There is the lost opportunity cost for the unrealized rental or income value lost when a commercial building cannot be located where a pond is required. This represents a continual annual and growing cost. Finally, there is the detention pond construction cost and higher liability costs.

An additional consideration is safety and aesthetics. The word pond emotes a pleasant image of fish jumping and ducks paddling. But there are two types of ponds for stormwater purposes and neither is all that attractive from a safety and aesthetic standpoint.

A retention pond retains water with most of the water expected to percolate into the soil below. Retention ponds are an attractive nuisance to children and can be dangerous in wet conditions as the slopes make it very difficult in rain and snow to escape once a child slides down the pitch. It is difficult to mow close to the edge and as a result tall grass and weeds end up collecting blowing trash. Fences placed for safety create garbage traps too—and the cyclone fence does not make for a very positive aesthetic.

A detention pond primarily slows water down from leaving the site and has similar challenges. Either type of pond is as likely to host floating garbage as floating wildlife and sedimentation quickly builds on the bottom of the pond reducing capacity and choking off infiltration.

Plenty of research and analysis has been done with porous pavements to prove the overall reduction in expense, as well as the danger reduction and improved aesthetics. With porous pavements, stormwater detention is built right into the open-graded base course to a depth required for the site—so runoff is captured at the source. The University of New Hampshire stormwater center has put together a case study showing the economic advantage of porous pavements. The concepts in this case study are valid for a wide range of porous pavements including modular pavers such as GEOPAVE aggregate pavers and GEOBLOCK grass pavers.

So when you are comparing porous pavements to traditional pavements, make sure you are considering all of the costs and safety implications that come with traditional pavement.

Choosing a green solution doesn’t have to cost more.

For more information on porous pavements, visit our web page: Porous Pavements.

    

 

Porous Pavements Myth Busters: Snow Removal

Written By: Samantha Justice, P.E.

What You Need to Know About Removing Snow from Porous Pavements

Vehicle and pedestrian use on porous pavements don’t stop because it’s winter. Roads need to be plowed, parking lots need to be cleared, and walking paths need to be snow and ice-free for safe use. This is true for all surface types: concrete, asphalt, and porous pavements—however, it is a common misconception that snow removal is more challenging with porous pavement systems.


Myth Busted: Snow removal on a Porous Pavement System (PPS) is easy!
Get the answers below to the frequently asked questions about removing snow from plastic, modular type porous pavers.

 

Can I Apply Salt to Porous Pavements?

Applying salt or ice melt chemicals to gravel-filled PPS surfaces encourages snow and ice to melt, the same as it would on a concrete road.

Most porous paver units are made with High Density Polyethylene (HDPE), a strong plastic that has a high resistance to environmental factors and is chemically inert. Cold temperatures and freezing and melting snow or ice will not cause damage or deformation to the paver material. Most importantly, HDPE is chemically stable, so it will not react to applied deicers, including road salt.

The added benefit to using a PPS is that the melting snow will infiltrate through the infill material and into the sub-base, minimizing the amount of surface water that could refreeze over time. With the ice at the surface removed or reduced, the insulating effect is gone, reducing the need for deicing salts by up to 70%. And you don’t need to worry about freeze-thaw issues in the base of the PPS either, because of how the open-graded aggregate’s high void space gives the water room to expand as it forms to ice. See More on Freeze-Thaw >>

Of course, deicers should only be used on aggregate infilled PPS as they would do damage to vegetated paver systems.

Can I Apply Sand to Porous Pavements?

Using sand, saw dust, kitty litter, or other abrasive materials on the surface of fallen snow can create traction to prevent slips, but doesn’t promote melting. More importantly, sand is only effective when it is on top–if it is buried or when the snow melts, the sand is ineffective.

Sand should not be used on PPS because it will eventually seep into the open-graded aggregate base underneath the paver units, causing it to clog. A clogged system will not work properly, leading to excessive maintenance requirements in the spring. Avoiding sand and other fine-grained materials will help keep the PPS in ready-mode for the next snowfall.

Can I Use a Snowplow on Porous Pavers?

When heavy snowfalls occur, you cannot rely on deicing alone. For residential or small porous pavement areas, using a hand shovel is perfect for clearing away the snow; but for larger areas, snowplows are the way to go. When plowing over any gravel areas—especially gravel-filled porous pavers–snow blade shoes are recommended. The snow blade shoes will protect the paver units, while avoiding excess wear or movement of the gravel material. When using the blade shoes, snowplows have no special requirements. Simply run the plow according to standard use.

If a blade shoe is not available, the plow’s blade should remain 1 to 2 inches above the paver system to avoid damaging the units or catching on the system. Typically, there isn’t a need for deicers as the warmth of the ground permeates through the open-graded base course and melts the thin layer of unplowed snow—but if desired, deicers can be applied to melt the remaining snow.

How Do I Remove Snow from Grass Pavers?

If the porous pavement system has topsoil infill and sprouts vegetation, then snow removal is typically not required. The grassed area should look and act like a regular lawn, so snow can accumulate and melt naturally. When the snow melts in the spring, maintain the vegetated porous pavement area in accordance with regular landscaping plans.

In the case where snow removal is required—such as an emergency lane—simply leave the blade up 2 inches and allow the remaining snow to melt off naturally. It may be necessary to have visibility poles marking the boundaries of the porous pavement area.

Making Winter Surfaces Safer

As you can see, snow removal on porous pavement systems is easy. Roads, parking lots and walking trails will not only be safer, but with a porous pavement system, drainage and runoff during the spring melt will not be an issue either.

Presto Geosystems offers the GEOBLOCK® grass and GEOPAVE® gravel porous pavement systems to help control stormwater, meet load requirements and suit landscape plans.

Watch this video to learn more about our PPS and start building green today.

For more information on porous pavements, visit our web page: Porous Pavements.

    

Porous Pavements Myth Buster: Clogging

Written By: Bill Handlos, P.E.

All Porous Pavements Do Not Clog

Well-designed porous pavement systems resist clogging

While it is important to design porous pavement systems (PPS) to resist the effects of silt, grit, sand and other fine material that can slow or stop infiltration of water – It is a common myth that all porous pavement systems eventually clog. On the contrary, a good PPS system design, simple but effective site design and careful construction inspection and field guidance can all but eliminate the clogging threat.

System design do’s and don’ts.

Cross-sections will vary according to the porous pavement systems selected, but there are some common concepts that need to be followed for successful, long-lasting percolation.

 

 

Never place filter fabric immediately below the porous pavement surface. Whether using pervious concrete, porous asphalt, polyethylene injection molded paving block (such as GEOBLOCK vegetated or GEOPAVE non-vegetated PPS) or concrete paving stone, your cross-section should allow free flow from the paving layer to the base and storage layers. The last thing you want is to trap water in your pavement layer. Surprisingly, at least one aggregate PPS manufacturer sells their product with a filter fabric attached to the bottom of the units.

Always use a filter fabric or other separator at the bottom of the base layer if the subbase contains fines that can move up into the open graded base course when saturated.

Choose wisely when specifying choker course and base gradation. A choker course is not necessary for polyethylene molded block products, since they ride on the surface of the open graded base course. It is necessary for brick pavers, pervious concrete and porous asphalt. You should select choker course materials carefully so as not to have them migrate into the base and create settlement problems. Choose too fine a material and you have settlement; choose too coarse and your paving surface will not place properly.

 

Common site design errors.


Drainage
is still important, but for different reasons. For impervious surfaces, positive drainage to avoid puddling is standard. For pervious surfaces, one has to consider drainage below the surface. The design needs to consider water moving through the base to the low spot of the pavement area. Be cautious not to discharge from the base up through the surface of the pavement course. Consider a 50-foot long pervious pavement driveway at a 4% slope. There would be 2 feet of fall from the high-end to the low-end and in a heavy rain event, water could become transient and flow out of the pavement at the low side. This horizontal transportation of water brings with it silt and sand that would become concentrated at the low-end of the pavement structure.

Another way that site design could create clogging is lack of consideration for off-pavement sheet flow. Whether it’s leaves, grass clippings, or silt and topsoil – pavement adjacent drainage can transport contaminants in heavy loading conditions. Cut off swales and site contouring can prevent this from happening.

Common installation errors.


Pervious concrete
should be a very stiff and dry mix. Adding water to the mix for workability at the site leads to the paste being pulled down by gravity and settling at the bottom of the concrete lift. With that thin layer of paste hardening, the high-volume water flow gets caught like a perched water table within the pervious concrete. This is not only bad for volume flow, but in cold-weather climates can create a standing water layer.

Gradations with a high degree of fines should be avoided for both aggregate polyethylene block style pavement as well as for open graded base course material. While there is no need for washed material, delivering material with high fines content essentially pre-contaminates your porous pavement system.

In some areas, river rock or brownstone is plentiful and inexpensive. The specifier should fight the urge to accept such stone as a substitute for crushed aggregate base course. Good porous pavement locks up and carries load well.

Some resin based block style products specify sand bases. While initially a coarse sand can drain adequately, it will quickly become clogged, water will saturate, pore pressures will rise and saturated conditions will lead to running.

How do you guarantee success?

Intelligent design by experienced manufacturers and engineers placed by seasoned contractors who understand that the details of the solution matter.

For more information on porous pavements, visit our web page: Porous Pavements.

    

 

Porous Pavements Myth Buster: Winter Durability

Written By: Bill Handlos, P.E.

Properly designed porous pavement systems do not get damaged by the dynamics of freeze-thaw cycles.

For decades, civil engineering roadway designers have been trained to use positive drainage, crack sealing, and sealcoating to keep the area under pavement dry. The prevailing mentality was to use well-graded, tightly compacted base under impervious concrete or asphalt wearing surfaces. When water gets between the well-graded base and the impervious surface—frost conditions would lift pavements, weaken base structure, create potholes and in general, wreak havoc with the life of the pavement.

  

So, it is not surprising that age-old tenets related to moisture, seepage and freeze-thaw cycles get mistakenly applied to porous pavement systems.

What makes well-designed porous pavement cross-sections so resistant to the power of freezing and expanding water? The answer is space. Poorly-graded crushed aggregate offers up to 40% void ratio which gives water a place to move, a place to expand into upon freezing, and a network of pathways to drain.

High void ratio systems allow the Earth’s natural warmth to move up from below the frost line into and through the open-air system just as water and ice-melt moves down and through the system. If the water can’t permeate into the ground and is trapped in the open-graded base system, the voids allow expansion of the water as it forms to ice to harmlessly expand into the void areas.

How Freeze-Thaw Affects Porous Pavement

There are more than one freeze types. There is the dry freeze and the hard dry freeze condition that describes regions with low precipitation and multiple freeze thaw cycles or only one or two freeze cycles, respectively. Neither of these freeze types challenge porous pavement systems, because they lack moisture.

There are wet freeze regions having 15+ freeze thaw cycles that require 6 to 12 inches of open-graded base course to safely allow expansion of the water that percolates and drains through the pavement and base throughout the cycles.

Then there is the more challenging hard wet freeze. This is the condition described by areas that have moderate to high precipitation combined with a frost depth that develops over the course of several months. The National Ready Mixed Concrete Association offers a solid set of recommendations defining open-graded base course depth and the porous pavement depth, based on 65% of the maximum frost depth for the area. So, an area that gets 24 inches of frost depth should design for a 16-inch total pervious cross-section. The 16 inches includes the porous pavement, the open-graded base course and any pervious subbase.

 

Concerns with freeze-thaw having negative effects on the performance of porous pavements is understandable, but simply a myth. Because of their high void space and ability to allow expansion of water to ice, freeze-thaw cycles have very little effect on porous pavements.

 

So, you can have all of the benefits of porous pavements—reduce detention pond system expenses, reduce land utilization for stormwater purposes, return water to the aquifer below and cut stormwater conveyance and structure costs—with the comfort of knowing that freeze thaw cycles will not damage your porous pavement.

For more information on porous pavements, visit our web page: Porous Pavements.