Pervious Paving Materials

Safari Thatch and Bamboo Wynand Odendaal PO Box 91286 Austin, TX 78709 (512) 448-2000 (512) 448-2319 fax

Pervious Paving Materials Contents:

CSI NUMBERS
DEFINITION
CONSIDERATIONS
COMMERCIAL STATUS
IMPLEMENTATION ISSUES
GUIDELINES

1) Installation
2) Grass Requirements
2) Use and Maintenance

RESOURCES

PROFESSIONAL ASSISTANCE
COMPONENTS / MATERIALS / SYSTEMS
GENERAL ASSISTANCE

025 100

Water-pervious materials such as gravel, crushed stone, open paving blocks or pervious paving blocks for driveways, parking areas, walkways, and patios minimize runoff from those areas, as well as increase infiltration. Some pervious paving options can retain turf and carry autos and trucks evenly without creating tracks or other heavy traffic wear signs. Many pervious surfaces that receive auto traffic require a clay-type roadbase subgrade. The roadbase material could slow water percolation in heavy rains and cause over-saturation above it, leading to puddles or runoff. It is best to select a pervious paving material that can use the most porous subbase. Care should be taken during installation to minimize excessive soil compaction.

A turf covered pervious surface can be problematic for certain types of footwear, and can stay wetter after rains due to the height of the grass. A compromise approach is to retain a small impervious walkway to accommodate the areas that provide access to vehicle loading and unloading.

Pervious materials will cost more than asphalt surfaces with some systems costing as much as 40% more. If used in areas with underground utilities needing repair, pervious paving materials can easily be removed from only the repair area. Pavement replacement is simplified and expensive measures such as asphalt cutting are eliminated.

	Commercial Status				Implementation Issues
Pervious Paving

Legend
	Satisfactory
	Satisfactory in most conditions
	Satisfactory in Limited Conditions
	Unsatisfactory or Difficult

TECHNOLOGY:

SUPPLIERS:

COST:

FINANCING:

PUBLIC ACCEPTANCE:

REGULATORY:

1.0 Installation

Pervious paving will function best with a similarly porous subgrade. This can be difficult given the clay soils in our area, and compaction which may occur during the construction process.

Contractors will need to take special precautions to prevent excessive compaction of the soil during the installation process.

Sediment should be prevented from entering the pore spaces of the paving blocks during and after installation. If the pore spaces of pervious paving become filled with sediment, the pervious nature of the finished product will be diminished.

Some pervious paved areas which will receive auto traffic may use interlocking pavers that have open spaces which allow grass to grow in the openings. This creates a surface combining good load-bearing capacity and large pervious openings.

A subbase consisting only of sand and gravel will have less ability to support grass roots growing into it. This restricts the grass root zone primarily to the topsoil directly above the subbase, and thereby can be subject to more rapid drying out in drought conditions. It is preferable to use a subbase that includes soil in the mixture of sand and/or gravel. This will permit better growing conditions for the grass.

Cultivation of grass in interlocking pavers will be most successful in medium to low traffic areas.

Paving systems that have distinct ridges above the soil level can prevent the crown of the plants from being crushed.

Certain systems interlock and thereby avoid ruts, cracking, or settling occurring in heavily traveled spots. Very heavy loads can be displaced by the interlocking feature.

Pervious paving areas can be used to facilitate groundwater recharge. Pervious paving can accept runoff from roofs and adjacent parking areas and allow it to infiltrate the ground. It can also reduce the need for curbs and gutters as drainage features.

Proper maintenance of permeable paving includes periodic vacuuming of the paving to remove sediment buildup. Vacuum-type street sweeping equipment, as opposed to equipment which sweeps only, is the most effective.

See "Engineers - Civil" in Yellow Pages

see "Paving Materials" in Yellow Pages

Presto Products Inc., Geosystems Divs.
P. O. Box 2399
Appleton, WI 54913-2399
(800) 558-3525

Geoblock(R) (interlock recycled plastic)
Caldwell Culverts (regional distributor)
PO Box 1248
Taylor, TX 76574
(800) 252-3737

Hastings Pavement Co.
30 Commercial St.
Freeport, NY 11520
(516) 379-3500
Checker Block(R) (concrete)

D'Hanis Brick
11931 Radium
San Antonio, TX 78216
(210) 525-8142
Corporate Office in San Antonio
Plant in D'Hanis, West of SA
Interlock pavers

Pavex Concrete Pavers
P. O. Box 1237
Round Rock TX 78680
(512) 244-7788
(concrete interlock pavers)

Uni-Group USA
4362 Northlake Blvd., Suite 109
Palm Beach Gardens, FL 33410
(800) 872-1864

Grid Paver (concrete)
Pavestone (regional manufacturer)
Katy, TX
(713) 391-7283

Pavestone Co. (regional manufacturer)
Grapevine , TX
(817) 481-5802

Invisible Structures
14704-d, E. 33rd Place
Aurora, CO 80011
(800) 428-1333
Grasspave 2(plastic rings from recycled plastic)

Concrete Grid Pavers
Interlocking Concrete Pavement Institute (ICPI)
1323 Shepard Drive
Suite D
Sterling, VA 20164
(703) 450-4998
(703) 450-1482 fax
icipi@mail.wdn.com

Concrete Grid Pavers
National Concrete Masonry Association
2302 Horse Pen Rd.
Herndon, VA 22071
(703) 713-1900

City of Austin ECSD Water Conservation Program
206 E. 9th St., Suite 17.102
Austin, TX 78701
(512) 499-2199

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