Numerous examples of concrete pavers outperforming life span projections can be found in the U.S. These projects have an assortment of different dimensions and paver types, base materials and subgrade characteristics, all of which are working above and beyond the specifier's initial expectations. About 130,000 square feet of concrete paver parking areas and roadways in this Inverness, Ill., office development have required no maintenance through 33 years of harsh winters.

An estimated 3-4 billion square feet of concrete pavers are installed worldwide every year. On a per capita basis, the United States lags behind many other developed countries in concrete paver usage.

Throughout Europe, for example, concrete pavers are primarily used for vehicular parking and municipal streets. In the U.S., however, pavers are primarily used for pedestrian applications and residential driveways. Why are pavers used so much more in the U.S. for pedestrian and light vehicular applications instead of streets and parking lots?

The Port of Tampa, Fla., installed 500,000 square feet of pavers in 1996, which continue to support heavy loads from steel products storage and the trucks that move them. Millions of square feet of concrete pavers in the U.S. and across the globe are used in major urban street arterials, heavy material handling yards and in port facilities, supporting critical load applications.

Design & Durability
Concrete and asphalt pavements have been used since the 19th century. Concrete pavers originated in the Netherlands and have been used since the 1950s.

Segmental paving, due to its higher aesthetic standard, is often held to a higher standard of performance. For instance, when a rut appears in a paver lot or street, the pavers are considered inefficient or substandard, despite the ease of replacement that comes from an interlocking paver system. When "D" cracks appear in concrete and "alligator cracks" appear in asphalt, however, the failure of the surfacing considered commonplace, if not likely. "Well, that's just concrete and asphalt," an installer might say, while arranging for repairs and replacements more demanding than fixing a loose or lost paver.

With over 5 million square feet of interlocking concrete pavement in service since 2004, the surfacing at the Port of Oakland, Calif., supports wheel loads 5 to 10 times heavier than highway trucks.

As a result, classical architecture and engineering constantly struggle for supremacy in final pavement design. Architects and landscape architects are generally in favor of visually interesting site amenities, and like to push the envelope; engineers tend to design within established systems, particularly when their training is in a narrow area of discipline. Both trades, however, seek positive and proven performance.

From a site designer's perspective, selecting hardscape boils down to a balance of scale, color and a congruent perspective of the various materials used on site. Segmental paving – specifically concrete unit pavers – can accommodate many elements, including multiple shapes, solid colors, blended colors and surface textures that can stand alone or be combined to meet a designer's intent. The selection and ability to combine these concrete paver shapes, colors and textures are unequaled in architectural paved surfaces.

The pavers that cover the streets in downtown Hamilton, Ontario (Tegula-Tec/PERMACON), have been supporting traffic, snow, salt and plows since 2002.

Standards & Specifications
Significant progress has been made in developing standard practices for concrete pavers in vehicular applications. For example, the American Society of Civil Engineers (ASCE) standard for the structural design of interlocking concrete pavements – ASCE/T&DI/ICPI 58-10 – was published in 2010 for the installation of municipal streets and roadways. The Interlocking Concrete Paver Institute (ICPI) has established a pavement condition index (PCI), a distress manual and an ASTM standard practice (ASTM E2480-11) for PCI surveys of interlocking concrete roads and parking lots. All of these validate concrete pavers as a cost effective and high performance pavement system.

All building materials have a design life and are subject to incorrect design and use of inferior materials and or construction practices. Any building material, whether used for a vertical or horizontal surface, has to have proper design elements, use steadfast materials and be constructed properly to prevent failures.

Built to replace worn asphalt pavement in 1985, this interlocking concrete pavement street in Dayton, Ohio, enhanced the neighborhood's historic character. Although installation costs are typically higher than asphalt, segmental concrete pavers can save municipalities and homeowners money on maintenance costs because of the ease and rarity of replacing the interlocking stones.

Specifications are only as good as the enforcement of those specifications. The ICPI has a full complement of concrete paver specifications, but the challenge is continuing education. Educating specifiers, installation contractors and general contractors is essential in expanding the use of segmental paving, and, ultimately, the surfacing's end-use performance. One area of the ICPI's educational focus is the Quality Control/Quality Assurance authority, and/or the involvement and inclusion of project inspectors.

Typically, segmental paving product installation and application is not common knowledge for building inspectors. The ICPI is dedicated to providing education and resources for all of these stakeholders.

Editor's Note: The Hamilton, Ontario pavers were incorrectly identified in an earlier version of this article. The text has been corrected.