A 1997 survey of North American aggregate producers by Vanderbilt University and C&D Recycling found that the markets for waste rebar removed from the concrete rubble appear to have increased from 1994 to 1997.

Concrete: The primary use of crushed concrete is as a replacement for road-base gravel. Other applications include use as an aggregate in asphalt or concrete. Concrete recycling is practiced in most areas of the country, and is most prevalent in areas where landfill tipping fees are high or aggregate is in short supply.

Based on data collected for the State of Washington from waste concrete processors and recyclers, it has been estimated that 1.4 to 1.5 million tons (1.3 to 1.4 million tonnes) of waste concrete in that state are recovered, crushed, and recycled annually.

Wood: Wood waste produced at construction sites generally has better potential for reuse than wood from demolition sites due to the ease of separating the materials. Wood processing facilities have sprung up in many areas of the United States in recent years, particularly in areas with high landfill costs.

Asphalt Shingles: According to the National Association of Home Builders, about two-thirds of the U.S. residential roofing market is made up of asphalt shingles. Common uses for recycled roofing asphalt include hot mix asphalt for paving, cold mix asphalt paving product, and new roofing materials.

For now the challenge of meeting specifications for paving and roofing materials poses a limit to the growth of these applications. Preconsumer manufacturing scrap (approximately one million tons (0.9 million tonnes) per year) is currently being used in hot mix asphalt.

Drywall (Sheetrock, Gypsum): Drywall is recycled by first separating the paper backing, which is recycled into new paper backing, and then remixing the gypsum and using it in the manufacture of new drywall. Recovered drywall is also used as animal bedding, cat litter, and as a soil amendment.

With $100 billion in new construction each year in the United States, and $126 billion in renovations, the recovery of materials from construction and demolition (C&D) has important economic and environmental implications.

To the extent that the debris from construction and demolition can be reused or recycled rather than thrown away, demand for virgin resources is reduced, the embedded energy in these materials is recaptured, and the need for increasingly limited landfill space is reduced.

In addition to these environmental benefits, C&D recycling may also yield economic benefits by providing an additional source of revenue for companies engaged in construction and demolition.

According to the U.S. Environmental Protection Agency, 136 million tons (123 million tonnes) of building-related C&D debris were generated in 1996.

Building demolitions account for 48 percent, or 65 million tons (59 million tonnes) per year, of the C&D waste stream. Renovations account for 44 percent, or 60 million tons (54 million tonnes) per year. And construction sites generate eight percent, or 11 million tons (10 million tonnes) per year.

Options for Recovery

There is an increasing trend toward recovery of C&D debris in the United States. Depending on local economic factors such a C&D landfill disposal (tipping) fees, labor costs, and market value of recovered materials, recovery may be competitive with disposal and may produce bottom-line savings.

Traditional clay brick still plays an important, expressive role in modern architecture, and to highlight a few North American examples of its application, the Brick Industry Association (BIA) announced in July 2006 the results of its annual Brick in Architecture awards.

In the words of BIA president Dick Jennison, “The winning projects demonstrate the versatility and enduring appeal of clay brick in today’s construction. Brick is, and always has been, a superior cladding material with unlimited design potential.”

One of the seven “best-in-class” award recipients, in the educational category, is the Oak Park Elementary School (2005) in Corpus Christi, Texas, by Richter Architects. The design reflects, in its texture and terra cotta color, the Hispanic origins of its regional culture.

At the school’s entry, metaphorical tree trunks bend upward to resemble building blocks and to recall the local masonry tradition. The twisted columns support cast stone arches, abstracted to echo the contemporary vernacular. The opaque street facade protects the classrooms from traffic noise and can withstand hurricane force winds, but the textured brick adds visual interest.

Reflecting Community

The Greek Orthodox Church of the Resurrection (2005) in Brookville, New York, was designed by Bentel & Bentel Ltd. to reflect a very different ethnic community. In its simple cubic forms and Greek cross plan, the new building echoes old-world churches.

Although the brick is a cladding for a steel frame building, the brick lintels and piers, corbelled window openings, and water and belt courses recall ancient traditions. The textural and color accents of clay brick extend into the interior. As a testament to the importance of masonry to the community, even the street signs are executed in brick and marble.

The Concord Hospital Addition (2003) by TRO/The Ritchie Organization adds 84,000 square feet (7800 square meters), a new cancer program, and an identifiable front door to this New Hampshire community. The architects sought to balance programmatic contradictions between technology and repose, open and private. They were able to do this with brick because they could cast modern forms in traditional materials, making large openings, curved walls, and accented coursing.

The brick evokes the vernacular architecture of Concord’s industrial past. While the brick is ubiquitous on this existing medical campus, the curves and pattern of the addition suggest a more modern aesthetic.

Picturing Agriculture

Of all the best-in-class award recipients, none reflected community and function as explicitly as the Farm Credit Services of America Corporate Headquarters (2002) in Omaha, Nebraska, designed by The Clark Enersen Partners. The brick detailing on the long west facade symbolically articulates the cycles of the agricultural calendar.

Each bay represents a month of farming activities through brick patterns, colors, and textures. Beginning at the north end, frozen winter ground is represented by a simple running bond brick pattern. As the ground is readied for planting, the brick show a bit of shadow � as when the plows cut the earth. When planting occurs, farther south along the facade, the textures become smaller, representing seeds. Single bricks scatter like fertilizer.

Entering the growth season, brick protrusions represent the first sprouts breaking through the soil. As growth matures, the brick rows get denser and more defined. Reaching the harvest, the brick patterns become less dense, representing the plant stubble. Finally, the brick pattern becomes flat again, representing the dormant frozen ground. Despite the visual storytelling, the facade is durable and requires relatively low maintenance.

Fitting In, Standing Out

The Copernicus Center (2001) in Chicago, designed by Harding Partners, received recognition in the governmental category. The fitness center for senior citizens is of a beige-colored, smooth-faced brick selected to complement the dark ironspot brick of the existing building.

The architects wanted the addition to be efficient and environmentally yet low-cost in construction and operation. Besides selecting durable and low-maintenance brick, they optimized daylighting to reduce electrical and cooling loads and selected high-efficiency mechanical, electrical, and plumbing equipment.

One of the seven best-in-class award recipients was not a building but a paving landscape project. Rundell Ernstberger Associates, LLC reconfigured McKinley Avenue on the Ball State University campus in Muncie, Indiana, by use of carefully chosen brick pavers. Formerly, a wide expanse of asphalt had allowed traffic to speed by, making it difficult for tens of thousands of students to cross safely.

The new design slows traffic and designates pedestrian crossings with material changes and raised planters. Color contrasts and beveled edges give the brick pavers a highly detectable pedestrian surface of assistance to the visually impaired. The brick pavers provide a unifying design element, relate to the brick and limestone campus buildings, and help create a sense of place.

One of the award recipients, the Four Seasons Centre for the Performing Arts (2006) in Toronto, Ontario, Canada, by Diamond and Schmitt Architects, Inc., has already been covered extensively in ArchitectureWeek, both in its design and its acoustics.

To “warm” the exterior walls, the Four Seasons architects chose a glazed brick high in iron and manganese that give it an iridescent quality and reflectivity. The mass of the brick also serves to buttress the building against external noise.

The Brick Industry Association represents suppliers, distributors, and manufacturers of clay brick and of related products. The association engages in a broad range of technical, research, marketing, government relations, and communications activities.