The Paver System
How It Works
St. Petersburg, Russia
Snow. Ice. Freeze. Thaw.
300 years and counting.
Talk about a durable system. Over 2,000 years ago the Romans built a 50,000-mile network of segmental paver roads that supported heavy traffic under harsh conditions. They used a three layer system similar to what we use today. Some of those ancient roads are still in use!
Most European cities have miles and miles of paver roadways. Operating in climates similar to Minnesota and Wisconsin, these paver systems have withstood hundreds of freeze/thaw cycles and heavy vehicular traffic.
The reason interlocking concrete pavers are your best pavement choice can be attributed to the proper installation of a time-tested, integrated system. There are several components to the system.
The existing soil under your driveway is excavated up to 12 inches deep and 12 inches wider than the driveway footprint, then compacted.
A woven fabric is placed between existing sub-soils and the aggregate base to provide long-term soil separation and stabilization to the base and to prevent the silt and other contaminating soil fines from seeping up into the aggregate. This confining action maintains the thickness and load-bearing capacity of the aggregate base, and also reduces localized stress by redistributing traffic loads over a wider sub-grade area. Fabric is widely used in our region due to prevailing soil and climatic conditions
The key to the long term performance of any paved surface is the base preparation. The thickness of the base is determined by traffic loads, soil strength, sub-grade soil drainage and climate. A general base thickness guideline for residential driveways in our region is 8-9 inches. Base material (crushed limestone, class 2) is placed, graded and thoroughly compacted. The base layer is slightly sloped to allow for water drainage away from buildings.
An edge restraint system around the perimeter of the pavers contains the bedding sand and holds the pavers tightly together to prevent spreading due to horizontal forces on the surface.
A one-inch thick layer of course washed sand is laid on top of the base and leveled. The sand provides a setting bed for the pavers. It also moves upward into the joints between the pavers and causes the pavers to interlock. Sand is also applied from the surface to fill the joints.
Interlocking Concrete Pavers
Pavers are laid in the sand bed with care taken to maintain straight bond lines and proper color mix according to the design you have selected. After all the pavers are laid, the surface is swept clean and a vibratory compacter is used on top of the pavers to set them into the sand bed. Additional sand is swept and vibrated into the paver joints. This process is what causes the surface to lock together.
Permeable paver installations use a deeper excavation, non-woven geotextile and modified base and joint filling system.