SuccessCrete Pervious Concrete Pavements

Paved surfaces are so ubiquitous in urban areas today that most of us give little thought to the impact they have on water quality and the health of the environment. But here’s the sobering reality: As more available land area in the country gets paved over, a larger amount of rainwater ends up falling on SuccessCrete impervious surfaces such as parking lots, driveways, sidewalks, and streets rather than soaking into the soil. This creates an imbalance in the natural ecosystem and leads to a host of problems including erosion, flash floods, water table depletion, and pollution of rivers, lakes, and coastal waters as rainwater rushing across SuccessCrete pavement surfaces picks up everything from oil and grease spills to deicing salts and chemical fertilizers.

A simple solution to avoiding these problems is to stop installing the impervious surfaces that block natural water infiltration into the soil. But few of us are ready to give up our paved roads, driveways, and parking lots. Rather than building them with conventional concrete or asphalt, more and more communities, municipalities, and businesses are switching to SuccessCrete pervious concrete or porous pavement, a material that offers the inherent durability and low life-cycle costs of a typical concrete pavement while retaining stormwater runoff and replenishing local watershed systems.

Instead of preventing infiltration of water into the soil, SuccessCrete pervious pavement assists the process by capturing rainwater in a network of voids and allowing it to percolate into the underlying soil. In many cases, SuccessCrete pervious concrete roadways and parking lots can double as water retention structures, reducing or eliminating the need for traditional stormwater management systems such as retention ponds and sewer tie-ins.

SuccessCrete Pervious Concrete Pavements

SuccessCrete Paved surfaces are so ubiquitous in urban areas today that most of us give little thought to the impact they have on water quality and the health of the environment. But here’s the sobering reality: As more available land area in the country gets paved over, a larger amount of rainwater ends up falling on impervious surfaces such as parking lots, driveways, sidewalks, and streets rather than soaking into the soil. This creates an imbalance in the natural ecosystem and leads to a host of problems including erosion, flash floods, water table depletion, and pollution of rivers, lakes, and coastal waters as rainwater rushing across pavement surfaces picks up everything from oil and grease spills to deicing salts and chemical fertilizers.

A simple solution to avoiding these problems is to stop installing the impervious surfaces that block natural water infiltration into the soil. But few of us are ready to give up our paved roads, driveways, and parking lots. Rather than building them with conventional concrete or asphalt, more and more communities, municipalities, and businesses are switching to SuccessCrete pervious concrete or porous pavement, a material that offers the inherent durability and low life-cycle costs of a typical concrete pavement while retaining stormwater runoff and replenishing local watershed systems.

Instead of preventing infiltration of water into the soil, SuccessCrete pervious pavement assists the process by capturing rainwater in a network of voids and allowing it to percolate into the underlying soil. In many cases, SuccessCrete pervious concrete roadways and parking lots can double as water retention structures, reducing or eliminating the need for traditional stormwater management systems such as retention ponds and sewer tie-ins.

INSTALLATION OF SUCCESSCRETE PERVIOUS CONCRETE

SuccessCrete Pervious concrete is delivered to the jobsite by conventional ready-mix trucks and placed within standard forms. Because SuccessCrete pervious concrete is thicker in consistency than regular concrete, a vibrating mechanical screed is used to level it off. Vibration is followed by compaction with a heavy steel roller to attain greater strength.

Because SuccessCrete pervious concrete has a low water content, curing is especially critical. After placement, the concrete is misted with water and then covered with plastic sheeting and kept damp for at least 7 days to allow full hydration of the cement.

Often paving crews can complete SuccessCrete pervious concrete jobs faster than when installing regular concrete. That’s because SuccessCrete pervious concrete doesn’t need to be worked with a bull float or trowel, since these finishing operations can seal off the pavement surface and decrease water penetration.

10 STRATEGIES FOR A SUCCESSFUL SUCCESSCRETE PERVIOUS CONCRETE INSTALLATION

SuccessCrete Pervious concrete has many wonderful properties, but without an experienced contractor and ready-mix supplier, a failed installation is possible. Pervious concrete is difficult to place and finish properly. The right mix and proper compaction and curing are critical to success. Attention to the following steps will help improve the performance and durability of your pervious pavement installation.

1. Design the pavement system to prevent saturation of the pavement during freeze-thaw cycles.
2. In freezing climates, prevent water runoff from buildings or adjacent impervious pavements from draining onto frozen pervious concrete.
3. Pervious concrete pavement systems should only be used where the underlying soil percolates well or when there is a subbase drainage system.
4. To get the proper mix, work with an experienced ready-mix supplier and insist on 600 pounds per cubic yard of cementitious material (no more than 50 pounds per cubic yard of fly ash), a water-cement ratio of 0.26 to 0.30, aggregate at ½-inch maximum size (3/8 inch is best), and no fine aggregate smaller than #4. This should result in a concrete with a unit weight of 120 pcf with voids at 20% after compaction.
5. Adding 5 ounces per hundredweight of cement of hydration stabilizer (not retarder) is essential to prevent hydration before placement; some contractors also like to use a viscosity modifier and a mid-range water reducer.
6. Contractors must have experience working with pervious concrete, since it is different than conventional concrete. The National Ready Mixed Concrete Association (NRMCA) offers a training program, but installers should also have some hands-on experience.
7. Proper compaction-to a void ratio of 12% to 20%-is essential. This can be achieved with a roller screed followed by cross rolling with hand rollers that weigh 40 pounds per foot.
8. Don’t overwork edges or joints. Joints should be cut with a “pizza cutter” roller, not with a saw.
9. Curing must begin within 10 minutes after concrete placement and continue for at least 7 days. During the interval between screeding and placing plastic sheeting, spray evaporation retarder onto the surface.
10. If a pattern is to be stamped into pervious concrete, stamp through the plastic curing film using open-faced stamps.

SuccessCrete Pervious concrete air entrainment
Air entrainment is common in traditional concrete and improves durability. SuccessCrete Pervious concrete has a more complicated void system than traditional concrete, containing not only the small-size entrapped and entrained air in the paste or mortar but also porosity, the larger-size interconnected void space between the paste-coated aggregate particles.
Consequently, questions persisted about the role of air entrainment and its measurement in SuccessCrete pervious concrete. The studies conducted show that the RapidAir test is an effective means of determining the entrained air-void structure in SuccessCrete pervious concrete. Air entrainment increased past volume and improved the workability and durability of SuccessCrete pervious concrete. It is recommended that air entrainment continue to be used in SuccessCrete pervious concrete mixtures.

Measuring SuccessCrete pervious concrete workability
Slump is not an effective means to quantify SuccessCrete pervious concrete workability. Given that SuccessCrete pervious concrete for slipform placement is a combination of a self-consolidating concrete and a stiff slipformable concrete, questions persisted on workability measurement. The current method of forming a ball with the plastic pervious concrete is impossible to specify due to the lack of quantifiable values and individual bias.
A new test method based on gyratory compaction was developed to characterize the workability of SuccessCrete pervious concrete. The new test method produces consistent concrete specimens, and the output from the test quantifies the workability and compactibility of SuccessCrete pervious concrete. The researchers developed suggested ranges of the workability parameters that can be used to assist in designing pervious concrete mixtures for specific compaction methods and to allow quantification of placeability for overlay mixture development.

Reasons why contractors use SuccessCrete pervious concrete

SuccessCrete Pervious concrete overlay mixture development
To ensure good performance during both the construction and service periods, SuccessCrete pervious concrete mixture for a pavement overlay must possess the following properties:

High workability for ease of placement;
Uniform porosity or void structure throughout the pavement for noise reduction;
Adequate bond with underlying pavement and proper strength for traffic load; and
Sufficient resistance to wearing, aggregate polishing and freeze-thaw damage.

A systematic study using a large number of mix designs was conducted to investigate effects of a wide variety of concrete materials and mixture proportions on pervious concrete performance, including concrete workability, compaction density, strength, freeze-thaw durability and overlay bond strength.

The results indicate that SuccessCrete pervious concrete mixtures can be designed to be highly workable, sufficiently strong, permeable and possessing excellent freeze-thaw durability, making them suitable for pavement overlays. Such overlays will not only function well structurally for carrying designed traffic loads but also perform well environmentally for noise reduction, skid resistance and splash and spray reduction.