Interlocking Pave Stones in Cold Climates

By Alva D. Logsdon

The interlock of the paving stones allows for three kinds of load transfers: vertical, horizontal and rotational interlock. Vertical interlock is achieved by shear transfera of loads to surrounding pavers. Horizontal is achieved through laying patterns such as herringbone. This disperses forces from vehicle breaking and accelerating. Pavestones provide rotational interlock when installed with an edge restraint.

Interlocking concrete pave stones continue to grow in popularity for pavement solutions. They offer unlimited design, structural stability and a low life-cycle cost. But for long-term landscape maintenance, they offer one of the more cost-effective alternatives due to their low-maintenance needs.

The interlock design of pave stones provides flexibility not available in other paving materials. The interlock provides many benefits, but one of the greatest is the ability to flex with the ground movement underneath. Extreme climates, such as more than 100 degrees of the Nevada desert mountain region and sub-zero temperatures in the rocky mountain areas, can play havoc with poured or stamped concrete causing them to crack and buckle. Interlocking pave stones are installed on a compacted base and bedding sand; spacer bars on the pavers allow for a uniform joint separation between pavers. The joints are filled with sand and compacted upon completion. The interlock design of pave stones provides flexibility not available in other paving materials. The interlock provides many benefits, but one of the greatest is the ability to flex with the ground movement underneath. Extreme climates, such as more than 100 degrees of the Nevada desert mountain region and sub-zero temperatures in the rocky mountain areas, can play havoc with poured or stamped concrete causing them to crack and buckle. Interlocking pave stones are installed on a compacted base and bedding sand; spacer bars on the pavers allow for a uniform joint separation between pavers. The joints are filled with sand and compacted upon completion. Pave stones should be installed in the proper thickness necessary for the application selected, either vertical, horizontal or rotational.

Tumbled interlocking concrete pavestones in earth tone blends enhance the ambience of the natural mountain beauty at these Colorado ski resorts. The interlocking design and installation base provide a greater resistance to freeze/thaw than monolithic paving systems.

Locations dominated by heavy clay soils have a high shrink/swell. In cold climates, the frost action or the constant freezing and thawing of moisture in pavement materials is an important factor in long-term maintenance. The accumulation of ice in the underlying soil which causes the pavement surface to rise or buckle is called frost heave. A pavement area is susceptible to freeze/thaw when water soaks into the pavement. When water is trapped in the pavement, the rise and drop of the temperature results in a freeze/thaw effect as it contracts and expands with the concrete. The freeze/thaw effect on cast-in-place (CIP) results in cracks and pavement heave, while asphalt forms potholes. Because concrete pave stones are installed on a bed of sand without mortar, and have a low absorption rate, they can expand and contract with the freeze/thaw cycles without cracking or heaving.

?EUR??,,????'??Sealing of pavers in cold weather areas provides added protection against de-icing salts, thus extending the life of the paver,?EUR??,,????'?? Midyett said. ?EUR??,,????'??Sealers may also reduce efflorescence. However, sealed systems must be maintained, increasing the overall cost of the system. Long-term benefits must be weighed against both up-front and maintenance costs.?EUR??,,????'??

This kind of paving is perfect for a snow bound environment. Because of warming temperatures and traffic, the snow melts and the water gets trapped in the pavement. When temperatures drop, the water freezes and expands. Other kinds of surfacing would heave, crack and form potholes.

Snow melting systems can reduce accidents, liability and snow removal expenses, according to the Interlocking Concrete Pavement Institute (ICPI). The use of de-icing salts is eliminated which keeps interior floor materials cleaner from pedestrian traffic. There are two kinds of systems that can be installed in-ground underneath pave stones. Electric systems use wires to radiate heat. Generally, electric systems have a lower initial cost, but a substantial operating cost. They involve a series of control switches, thermostats, and snow-sensors. Liquid systems use a mix of hot water and ethylene or propylene glycol mix in flexible pipes. They have a higher initial cost, but a lower operating cost. Hot water systems consist of flexible pipes, pipe manifolds, pumps, switches, a water heater, thermostats, and snow sensors. They typically rely on a boiler that is also used to heat a building. Snow melting systems can be part of new construction or added later. Snow melt systems turn on automatically when a snowstorm starts, eliminating plowing, ice hazards, and the need for de-icing salts.

Underground repairs to utilities, irrigation systems and/or snow melting systems is inevitable. Concrete pave stones provide a virtual pavement zipper allowing for easy underground access and lower repair costs. Paving stones can be removed and palletized for space efficiencies while repairs are underway. Upon completion of underground repairs, the pave stones can be replaced without a scar to the pavement. The original pavement design is intact and no additional costs are incurred for material removal or pavement replacement. The process of using the same paving stones is called reinstatement. Unlike asphalt or CIP, interlocking pavements can be opened without a jackhammer. The first paver can be removed with a screwdriver or paving stone extractor. Subsequent pavers can be removed manually or mechanically. The need for street resurfacing caused by repeated utility cuts is eliminated because concrete pave stones are not damaged in the reinstatement process. A good installation crew can comprise a trained foreman and three good installers. A good four-person crew should be able to lay an average of 800 to1000 square feet per day. Some crews can lay up to 2,000 square feet per day. Since pave stones require no time to cure, pavement is immediately accessible by pedestrian or vehicular traffic. Today, paved areas are factored into the overall landscape design providing aesthetic beauty. Attractive pave stone streets and walks without ugly patches positively enhance landscape design and property value.

The interlock of the paving stones allows for three kinds of load transfers: vertical, horizontal and rotational interlock. Vertical interlock is achieved by shear transfer of loads to surrounding pavers. Horizontal is achieved through laying patterns such as herringbone. This disperses forces from vehicle breaking and accelerating. Pavestones provide rotational interlock when installed with an edge restraint.

When properly installed, interlocking paving stones require virtually no maintenance. As with any pavement, they can become soiled over time depending on the amount and type of use. However, paving stones can be cleaned and for stubborn stains, individual pavers can be replaced with no disruption to pavement design. Interlocking pave stones can be used for a variety of applications including pedestrian, light and heavy vehicular traffic. They are also available in permeable pavers which decrease stormwater runoff due to their infiltration, detectable warning for crosswalk safety, and turfstone for areas requiring vegetation. Interlocking concrete paving stones successfully weather freeze/thaw and shrink/swell conditions while offering an unlimited pallet of pavement design options. Landscape design expressions are enhanced through a wide variety of paver colors, shapes and textures.