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Quick Repair of Track Subgrade & Railroad Right-of-Way

Posted by Katie Bocskor

GEOWEB® Geocells — Quick Fix, Long Term Protection

Be prepared to repair washouts and track issues quickly and economically with one solution. The GEOWEB® 3D Soil Stabilization System is a proven 40-year solution, delivering emergency repair for track and railroad right-of-way embankments, bridges and channels.

Stock readily available allows for fast deployment by local railroad crews. Contact us for more information about our GEOWEB Emergency Repair Kit Stocking Program.

  • Wash Out Repair & Armoring:
    Right-of-Way Embankments | Earthen Berms | Bridge Protection | Drainage Channels
  • Variable Infill Options:
    Soil/Vegetation | Aggregate | Concrete

Economical Solution:

  • Less Down Time: GEOWEB material is quickly installed to repair any size emergency and minimize track disruptions.
  • Installation Benefit: Railroads can install the GEOWEB material with their own crews.
  • Reduce Rock Size: Rock confined in the GEOWEB structure replaces expensive rip-rap, reducing aggregate size up to 10 times.

Fast Deployment:

Strong, yet light-weight GEOWEB sections are easy to transport and quick to deploy, even in difficult site access areas. Most repairs do not require large construction equipment.

The GEOWEB structure with select infill stabilizes track ballast, and right-of-way embankments, earthen berms, drainage channels and earth retention structures.

 

Construction & Repair Versatility

The GEOWEB Soil Stabilization System has been successfully employed for railroad construction and repair for over 40 years.

  • GEOWEB sections are packaged in collapsed, easy-to-handle sections and are expanded into place on site.
  • Each GEOWEB section is 8.5 ft. wide x 27 ft. long and covers 230 sq ft.
  • Ideal for constructing and repairing track ballast, access roads, embankments, earthen berms, bridges, channels and right-of-way areas.
  • Low cost, locally available infill may be used instead of more costly imported infill.

GEOWEB STOCK COVERAGE:

  • 1 Pallet = 2,700 sq ft
  • 1 Truckload = 120,000 sq ft

ATRA® Key Connection Device:

  • Connects the GEOWEB sections quickly, easily and safely. Learn more >>


Track Ballast Support for New Track or Repair:
The GEOWEB System stabilizes the ballast material, reducing differential settlement and aggregate thickness by 50% or more.

 

 

 

 

 

 

 

 

Right-of-Way Repair Examples

Washout Repair: Right-of-way draining channel repair. GEOWEB sections are installed quickly in tiers, and may utilize local infill. Vegetated fascia is attractive and eco-friendly.

 

 

 

 

Eroded Shoreline Repair: Track derailment repair. GEOWEB System created a stable platform and tiered retaining wall to stabilize the right-of-way embankment.

 

 

 

 

 

 

 

Slide Repair: Track right-of-way repair. The GEOWEB system stabilizes embankments prone to slides from saturated or unstable soils. Aggregate infill allows drainage and minimizes maintenance.

 

 

 

 

 

 

Get a Quote | Request a Free Project Evaluation | Visit Railroad Website

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

Posted by Ashley Beyer

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

Posted by Ashley Beyer

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

Posted by Katie Bocskor

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

Posted by Katie Bocskor

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

Posted by Katie Bocskor

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/porous pavements. Traditional asphalt and concrete parking lot surfaces create significant stormwater runoff, and many municipalities do not allow them in expansion or new build situations.

When the entire parking area is constructed using a porous pavement system, stormwater concerns are greatly reduced. Depending on the type chosen, pavements that return rainwater to the aquifer nearly eliminate stormwater runoff and reduce sheet flow and point load erosion problems at the pavement edges. They also reduce the need for additional stormwater infrastructure to convey the water away from the area. Integrating porous pavement systems with asphalt and concrete surfaces can 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 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 on 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 drains 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, you must 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 combination of pervious and impervious surfaces can solve 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-surface 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?

Posted by Katie Bocskor

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 used for 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:

The University of Kansas Geotechnical Laboratory tested the performance of the GEOTERRA and GEOTERRA mat systems over weak to intermediate subgrades with CBR values ranging from 1% to 4%. They conducted a total of 12 tests to identify threshold and limit conditions, create a data-set for modeling, and determine the equivalent crushed aggregate base.

Testing Procedure:

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:

  • The 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.
  • The 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

Posted by Katie Bocskor

Written By: William G Handlos, P.E.

Does a porous pavement solution cost more?

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

Traditional pavements such as bituminous asphalt or Portland cement concrete enjoy low cost and ubiquitous installation contractors. This information may lead one to think that choosing a porous pavement would lead to higher overall project costs, but that is a myth because almost 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 pipes, 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. The impact of the land utilized for detention ponds does not end there.

Lost rental or income value is another cost consideration. Ponds take up valuable commercial or residential real estate, representing 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” often calls to mind pleasant images of fish jumping and ducks paddling; however, ponds constructed for stormwater management purposes are rarely attractive from a safety perspective or aesthetics standpoint.

A retention pond retains water as it percolates into the soil below. Retention ponds pose a safety concern to children and can be especially dangerous in wet conditions because 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. Additionally, the cyclone fence does not make for a very appealing aesthetic.

A detention pond’s primary purpose is to slow the water down from leaving the site, and these structures experience similar challenges. Both types of stormwater ponds are prone to collecting floating garbage and wildlife. This excess of organic matter causes sedimentation to build up at the bottom of the pond, reducing capacity and choking off infiltration.

A wealth of research proves that porous pavements contribute to an overall reduction in project cost and hazard mitigation while meeting aesthetic requirements. 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 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 the GEOPAVE® Gravel Pavers and GEOBLOCK® Grass Pavers.

When comparing porous pavements to traditional pavements, make sure you consider all of the costs and safety implications that come with traditional pavements.

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

Posted by Katie Bocskor

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

Posted by Katie Bocskor

Written By: Bill Handlos, P.E.

Not All Porous Pavements Clog

Well-designed porous pavement systems resist clogging

When designing porous pavement systems, it is important to consider the effects of silt, grit, sand, and other fine material that can slow or stop water from infiltrating. However, it is a common myth that all porous pavement systems eventually clog. 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 selected, but following some simple practices can ensure a successful system with long-lasting percolation.

Never place filter fabric immediately below the porous pavement surface. Whether you are using pervious concrete, porous asphalt, polyethylene injection-molded paving block (such as GEOBLOCK vegetated or GEOPAVE aggregate 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 but is necessary for brick pavers, pervious concrete, and porous asphalt. You should select choker course materials carefully to prevent them from migrating into the base and creating settlement problems. Choosing a material that is too fine may cause settlement, and choosing one that is too coarse will prevent your paving surface from placing 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 carries silt and sand that would become concentrated at the low-end of the pavement structure.

 

Another way that site design could create clogging is a 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 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, 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 to Guarantee Success

Intelligent design by experienced manufacturers and engineers and installation by seasoned contractors will ensure success.

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