Posts Categorized: Grass Pavers for Porous Paving (GEOBLOCK)

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… Read more »

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… Read more »

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,… Read more »

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… Read more »

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…. Read more »

How Well Do You Know Your Competition? Try Installing Them.

Written by William G Handlos, P.E. Presto Geosystems is the maker of the Genuine GeoBlock® family of rigid vegetated porous pavement products. We’ve been manufacturing porous pavements since 1978 and have been a leader in the industry ever since. It’s safe to say we were pretty comfortable with our understanding of the differences between our products and our competitors in the market….or so we thought.  We knew our products were premium performers offering the best structural modulus (load spreading snowshoe effect), more structural high density polyethylene per square foot than our competitors, load transfer tabs to assure no separation at joints and an industry-leading warranty. Our competitors on the other hand  go with much lighter density product design and some offer their products on rolls like carpet or rolls of sod.   We knew a product that comes on a roll was not a very effective load transfer device. After all, the whole point of vegetated porous pavement is to protect the topsoil (and therefore the root system) from damaging compressive forces and to transfer those forces to the layer below the topsoil – preventing rutting and offering a stable riding surface for fire lanes, overflow parking, or occasional use… Read more »

A Simple Question

Written by: William G. Handlos, P.E. How long does it take to install? It is a question we hear every day. When it comes to cost and installation rates for geosynthetic construction products, there are no simple answers to what seems like simple questions. In fact, beware of those who try to simplify determination of installation costs for their products with quick answers or charts and tables to determine construction rates. Experienced project managers and site supervisors of the crews charged with installation are in the best position to estimate productivity rates. They know best their crew’s capability and the characteristics of the site involved. The variables that need to be considered include: Crew size, talent, work ethic and workday length Temperature, precipitation and length of day (sunlight) Experience with product class Size of the project Site Access Site Conditions (see weather) Crew The optimum crew size is important. Too small and you may lose the benefits of assembly line productivity. Too large and you will find that you fall over each other and pay for extra “inspectors”. All crews are not created equally. The familiarity with tools and techniques vary greatly as does the work ethic both between crews and… Read more »