Beauty That Endures

Words: Bronzella Cleveland

A look at the enduring value and timeless beauty of genuine clay pavers

Best in Class – Image courtesy of Tim Hertel. – Brick manufactured by Whitacre-Greer.
Best in Class – Image courtesy of Tim Hertel – Brick manufactured by Whitacre-Greer.

Americans have used clay brick pavers on pedestrian pathways and roadways since early Colonial days, because genuine clay pavers add stature, character and long-term appeal. Can you imagine what Georgetown, Old Town Alexandria, Va., and Boston’s Beacon Hill would look like now, had the sidewalks been paved (or repaved) in a material other than genuine clay pavers?

Often a premium choice for their aesthetic appeal, there also are a number of compelling performance reasons to choose clay pavers that may surprise some designers. Some of these are discussed below along with key information to aid in the design of clay pavements.

Compressive strength

Many designers are surprised to find just how strong clay pavers are. The minimum strength requirements of ASTM C 902 pavers are the same as concrete pavers and can support all but the heaviest vehicular loads, which can be supported by higher strength ASTM C 1272 pavers. The compressive strength for the most widely available pavers averages around 14,000 psi – high enough to meet both standards and typically stronger than either concrete pavers or poured concrete. Some clay pavers have compressive strengths exceeding 36,000 psi and are generally resistant to abrasion, stains, deicing salts and other corrosive elements. Keep in mind during design that the pavers are only one wearing surface of the pavement and all layers must be designed properly to support loads and to perform as expected.

Brick Industry Association resources

No matter the product and installation method you choose, the Brick Industry Association can help you achieve your desired outcome. To find out more information on genuine clay pavers, visit www.gobrick.com/pavers. This site includes the latest technical information, including the Technical Notes 14 Series, a presentation on the municipal use of clay pavers, various case studies, a guide specification, and a list of manufacturers who sell and distribute genuine clay pavers.

Brick Industry Association resources

No matter the product and installation method you choose, the Brick Industry Association can help you achieve your desired outcome. To find out more information on genuine clay pavers, visit www.gobrick.com/pavers. This site includes the latest technical information, including the Technical Notes 14 Series, a presentation on the municipal use of clay pavers, various case studies, a guide specification, and a list of manufacturers who sell and distribute genuine clay pavers.

Brick Industry Association resources

No matter the product and installation method you choose, the Brick Industry Association can help you achieve your desired outcome. To find out more information on genuine clay pavers, visit www.gobrick.com/pavers. This site includes the latest technical information, including the Technical Notes 14 Series, a presentation on the municipal use of clay pavers, various case studies, a guide specification, and a list of manufacturers who sell and distribute genuine clay pavers.

Durability and permanent color retention

The unsurpassed durability and rich, intense color of a clay paver is one of its most desirable and enviable attributes. Amazingly, many of the brilliant, red pavers that people stroll on when walking through Boston’s Beacon Hill have been in service for more than 200 years. While lower initial-cost options are available, this longtime track record speaks volumes about the durability, quality and value of clay pavers.

The reason for the superior color retention of clay pavers is that the color is from natural impurities within the clay, which means that color is consistent throughout the body of the unit and will not fade because of weathering. Other concrete-based products, colored by pigments or dyes, may fade or require application of sealants to maintain their color after installation.

Sustainability

Clay pavers can provide multiple benefits to sustainable design. The small size, modular nature and minimal packaging of brick result in little onsite construction waste. Pavers can be re-used or crushed and recycled for new uses, thus avoiding the landfill. Flexible or permeable clay pavements can reduce stormwater runoff and filter pollutants. In addition, light colored pavers can reflect a significant amount of solar energy, reducing the heat island effect. Further, brick paving can be used as part of several passive solar design strategies in interior applications to store heat and moderate temperature swings. Finally, flexible pavements allow relatively easy access to utilities or services that lie beneath the pavement, and the pavement often can be restored with the original materials and no evidence of repair.

Safety and accessibility

Research from the University of Pittsburgh proves that properly installed clay pavers can meet or exceed the American with Disabilities Act requirements and Public Right-of-Way Accessibility Guidelines by not increasing the amount of work required for mobility and offering less severe vibration than poured concrete sidewalks. Ensuring that joints between pavers aren’t too wide and that differences in height between adjacent pavers are kept to a minimum reduces work and potential trip hazards. It also assures an ability to compete with other pavement options as an accessible surface.

Best in Class - Image courtesy of Tim Hertel. - Brick manufactured by Whitacre-Greer.
Best in Class - Image courtesy of Tim Hertel. - Brick manufactured by Whitacre-Greer.

Texture also has an impact on slip and skid resistance; most clay pavers exceed minimum slip resistance values. Some pavers are manufactured with a more pronounced texture or surface pattern. Surface features – including a grid of dimples or domes – also can be imprinted into the surface of the paver before firing.
Clay pavers also can be designed to have another benefit in vehicular applications – traffic calming. Much like rumble strips on the highway, the sound produced as cars ride over clay pavers can cause drivers to slow down, reducing traffic speed and promoting safety in pedestrian areas.

Design flexibility

The relatively small size of clay pavers creates a pavement surface with human scale. And the wide color selection makes clay pavers an ideal material to blend with unique designs, bands, borders and panels. Changing the surface texture also can accentuate the contrast in different areas or bands. Additionally, many bonding patterns can be used when laying clay pavers. Some of the most popular include herringbone, running bond, stack bond and basket weave.

When choosing a pattern, considerations should include the setting bed of the pavement, horizontal loads and the need for dimensional precision. Vehicular loads typically generate the largest horizontal load on a pavement. Sand and bituminous setting beds are more prone to paver creep when subject to the horizontal loads caused by vehicles. Herringbone bond best distributes horizontal forces across a pavement, reducing the potential for creep. Running bond and other patterns with continuous joints do not distribute horizontal loads as well as herringbone bond and should have their joints oriented perpendicular to the direction of traffic.

Keep in mind that clay pavers are the perfect complement to clay masonry. Designers often anguish over finding the perfect material and color that fits their vision for a project. Clay pavers can be used along with clay masonry to harmonize the landscape into that vision.

Pavers aren't just red - Image courtesy of Boral Pavers
Pavers aren't just red - Image courtesy of Boral Pavers

Color and texture selection

It’s not uncommon to think of various shades of red in a highly textured unit when clay pavers come to mind. However, with today’s manufacturing technology, clay pavers are available in more colors and textures than ever before, including some that are unique to clay brick and can’t be attained, or maintained, by other materials. For example, it is possible to get pavers ranging in color from polar white all the way to jet black that are extremely smooth and dimensionally precise. Clay pavers also come in a wide array of earth tones, pinks, oranges and burgundies, which work well alone or when blended together. Since clay pavers are made from natural materials, there may be some inherent color variations between different production runs. Using a field panel to establish acceptable color variations and laying pavers taken from different cubes of pavers helps reduce noticeable variation.

Specification, installation and maintenance

Clay pavers can provide a durable walking or riding surface that is beautiful and smooth for an extremely long period. The key to success, as with any building material, consists of proper specification, installation and maintenance. Because the initial planning plays such a key role in determining the ultimate success of a project, contractors and designers should take special care in determining which installation method makes the most sense for their project. Table 1 provides an overview of the strengths and weaknesses of each installation method.

Table 1. Comparison of Pavements Made with Clay Pavers
Clay Pavers On:AdvantagesDisadvantages
Sand Setting Bed on
Aggregate Base
Most durable
Cost-effective
Easy access to repair underground utilities.
Good as overlay to existing asphalt or concrete pavement.
Allows use of semi-skilled labor.
Can be designed as a permeable pavement.
May require a thicker base.
Intensive cleaning may erode joint sand.
Sand Setting Bed on
Asphalt Base
Good as overlay to existing asphalt pavement.Intensive cleaning may erode joint sand.
Sand Setting Bed on
Cement-Treated Aggregate Base
Good over poor soils or in small, confined areas.
Good as overlay to existing concrete pavement.
Intensive cleaning may erode joint sand.
Sand Setting Bed on
Concrete Base
Good over poor soils or in small, confined areas.
Good as overlay to existing concrete pavement.
Intensive cleaning may erode joint sand.
Requires good drainage above base.
Susceptible to greater offset with subgrade movement.
Bituminous Setting Bed on Asphalt BaseReduced horizontal movement and uplift.
Enhanced water penetration resistance.
Repairs are more difficult and expensive.
Little tolerance for paver thickness variations or inaccurate base elevations.
Bituminous Setting Bed
on Concrete Base
Reduced horizontal movement and uplift.
Enhanced water penetration resistance. Good over poor soils or in small, confined areas.
Repairs are more difficult and expensive.
Little tolerance for paver thickness variations or inaccurate base elevations.
Mortar Setting Bed Bonded to Concrete BaseGreater tolerance for paver thickness variations or inaccurate base elevations.
Can be used on steeper slopes and greater vehicle speeds.
Drainage occurs on the surface.
Movement joints must align through entire paving system.
Least cost-effective.
Mortar joint maintenance required.
Repairs are most difficult and expensive.
Mortar Setting Bed Unbonded to Concrete BaseGreater tolerance for paver thickness variations or inaccurate base elevations.
Movement joints in setting bed and base are not required to align.
Preferred when used over elevated structural slab.
Bond break must be used to avoid stresses caused by horizontal movement between layers.
Least cost-effective.
Mortar joint maintenance required.
Repairs are most difficult and expensive.

Clay pavers on a sand setting bed with an aggregate base is the system we encounter most often today. Although many factors determine the performance of this or any paving system, some that warrant particular attention are compaction of the base material, consistent joints between pavers, drainage and maintenance. Adequate compaction of the pavements supporting layers (typically to 95-percent maximum density) is necessary to prevent deformation under load and uneven settlement, which will become apparent in the paver surface. Using under-sized equipment or trying to compact too thick of a layer will not provide adequate compaction. When using a plate vibrator, 3 inches or less of base material should be compacted at one time; this often necessitates compaction in multiple layers. Hand tampers or other small compaction equipment may be needed to prevent settlement near pavement edges, corners, features (tree pits, flag poles, etc.,) or confined areas that are not accessible to larger compaction equipment. A geotextile also may be used to separate pavement layers and prevent their integration, thus reinforcing and helping each layer to retain its strength.

McKinley Avenue at Ball State University

McKinley Avenue at Ball State University

Achieving the desired outcome

By Brian E. Trimble, P.E., CDT, LEED AP

For years, McKinley Avenue existed as a wide expanse of asphalt and a busy city artery passing directly through Ball State University (Muncie, Ind.), making it difficult for students to cross. Many of the students themselves compounded the hazardous driving conditions by stepping out indiscriminately all along the length of the street. The university realized a safer solution was needed. The street still had to carry vehicular traffic, including city and university buses, while simultaneously providing complete pedestrian access.

The innovative solution from the landscape architects at Rundell Ernstberger Associates, also of Muncie, Ind., calmed the vehicular traffic by incorporating a raised planter median between north- and southbound lanes. Several designated mid-block crossings were added, which alert drivers to the students. Pedestrian areas in the medians also provide increased safety, as students are no longer forced to wait for both lanes of traffic to clear before crossing. Clay brick pavers were a logical choice for the project for several reasons, including efficiency, sustainability and permanent color. Additionally, they have a durability that results in reduced maintenance and replacement requirements.

McKinley Avenue at Ball State University

The entire roadway was rebuilt with a concrete base with a bituminous setting bed. Subbase drainage was included as well to take care of moisture below the base. The use of clay pavers in a bituminous setting bed is frequently used in vehicular applications since it can resist the forces of many automobiles traveling at the same time. The braking and turning forces are often greater than some of the vertical forces because of the vehicles’ weight. This system, along with strong concrete curbs, will resist the forces and allow the pavement to stay in place for a long time.

The extensive use of clay brick pavers also helped integrate the streetscape with the surrounding buildings. With traffic moving more efficiently than before, this unique and aesthetically pleasing environment is now safer and friendlier for pedestrians. Once an intrusion, the transformed street has become a campus showcase.

McKinley Avenue at Ball State University

McKinley Avenue at Ball State University

Achieving the desired outcome

By Brian E. Trimble, P.E., CDT, LEED AP

For years, McKinley Avenue existed as a wide expanse of asphalt and a busy city artery passing directly through Ball State University (Muncie, Ind.), making it difficult for students to cross. Many of the students themselves compounded the hazardous driving conditions by stepping out indiscriminately all along the length of the street. The university realized a safer solution was needed. The street still had to carry vehicular traffic, including city and university buses, while simultaneously providing complete pedestrian access.

The innovative solution from the landscape architects at Rundell Ernstberger Associates, also of Muncie, Ind., calmed the vehicular traffic by incorporating a raised planter median between north- and southbound lanes. Several designated mid-block crossings were added, which alert drivers to the students. Pedestrian areas in the medians also provide increased safety, as students are no longer forced to wait for both lanes of traffic to clear before crossing. Clay brick pavers were a logical choice for the project for several reasons, including efficiency, sustainability and permanent color. Additionally, they have a durability that results in reduced maintenance and replacement requirements.

McKinley Avenue at Ball State University

The entire roadway was rebuilt with a concrete base with a bituminous setting bed. Subbase drainage was included as well to take care of moisture below the base. The use of clay pavers in a bituminous setting bed is frequently used in vehicular applications since it can resist the forces of many automobiles traveling at the same time. The braking and turning forces are often greater than some of the vertical forces because of the vehicles’ weight. This system, along with strong concrete curbs, will resist the forces and allow the pavement to stay in place for a long time.

The extensive use of clay brick pavers also helped integrate the streetscape with the surrounding buildings. With traffic moving more efficiently than before, this unique and aesthetically pleasing environment is now safer and friendlier for pedestrians. Once an intrusion, the transformed street has become a campus showcase.

McKinley Avenue at Ball State University

McKinley Avenue at Ball State University

Achieving the desired outcome

By Brian E. Trimble, P.E., CDT, LEED AP

For years, McKinley Avenue existed as a wide expanse of asphalt and a busy city artery passing directly through Ball State University (Muncie, Ind.), making it difficult for students to cross. Many of the students themselves compounded the hazardous driving conditions by stepping out indiscriminately all along the length of the street. The university realized a safer solution was needed. The street still had to carry vehicular traffic, including city and university buses, while simultaneously providing complete pedestrian access.

The innovative solution from the landscape architects at Rundell Ernstberger Associates, also of Muncie, Ind., calmed the vehicular traffic by incorporating a raised planter median between north- and southbound lanes. Several designated mid-block crossings were added, which alert drivers to the students. Pedestrian areas in the medians also provide increased safety, as students are no longer forced to wait for both lanes of traffic to clear before crossing. Clay brick pavers were a logical choice for the project for several reasons, including efficiency, sustainability and permanent color. Additionally, they have a durability that results in reduced maintenance and replacement requirements.

McKinley Avenue at Ball State University

The entire roadway was rebuilt with a concrete base with a bituminous setting bed. Subbase drainage was included as well to take care of moisture below the base. The use of clay pavers in a bituminous setting bed is frequently used in vehicular applications since it can resist the forces of many automobiles traveling at the same time. The braking and turning forces are often greater than some of the vertical forces because of the vehicles’ weight. This system, along with strong concrete curbs, will resist the forces and allow the pavement to stay in place for a long time.

The extensive use of clay brick pavers also helped integrate the streetscape with the surrounding buildings. With traffic moving more efficiently than before, this unique and aesthetically pleasing environment is now safer and friendlier for pedestrians. Once an intrusion, the transformed street has become a campus showcase.

Consistent joint widths can be critical to achieving the expected performance from sand-set pavers. The optimum width for sand joints is 1/8 of an inch. Joints that are too wide may not develop the friction needed to provide interlock, which keeps the pavers in place and helps distribute loads. Sand is more easily lost from wider joints, which can lead to a reduction in interlock and pavement performance over time. Wheels also tend to experience more vibration when traveling over wider joints. Conversely, thin joints do not allow an adequate amount of sand between pavers to develop interlock and prevent contact between adjacent pavers, which can result in chipping.

Adequate drainage is important to the performance and durability of the paving system and all its layers. Although the potential for water-related problems varies between projects, a few basic recommendations help to ensure desired performance. General slope of any brick paving system should be at least 1/4 of an inch per foot. Pavers should be installed about 1/8 of an inch higher than drains and pavement edges to minimize ponding. Since some water will permeate sand joints, weeps (covered or wrapped in a geotextile to prevent sand loss) or drainage mats may be needed to prevent saturation of the setting bed.

Ongoing inspection and maintenance are critical to continued performance of any pavement. Regular inspection can discover deficiencies and allow repair before the pavement becomes unserviceable or inaccessible. Conditions to look for include lippage between pavers, lost joint sand, ponding water, or damaged pavers. Small elements like clay pavers generally allow small, localized repairs, that when completed promptly, result in minimal effort and disruption. Considering the maintenance requirements during the design phase can assist in choosing a system that is cost-effective over the long term.

Read the case studies on page 26 and below to see how the installation system is used to help achieve the desired outcome for the project.

Leroy Danforth, EIT, LEED AP, is the architectural outreach manager for the Midwest/Northeast Region in the Brick Industry Association (BIA), providing technical assistance and educational programs on brick construction for architects, engineers, builders and other construction industry professionals. A former manager of BIA’s technical publications, Danforth also helps maintain BIA’s Technical Notes series.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Crossings at Corona

Photos courtesy of NUVIS.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

The landscape architect for this project was NUVIS. Pacific Clay Products supplied the brick.

Finding balance was a high design priority for the landscape design of the Crossings at Corona, a 113-acre regional retail center in Corona, Calif. A key element in meeting this challenge was providing a hardscape that not only evokes a comfortable and natural environment in a suburban entertainment/lifestyle complex, but also incorporates sustainable design principles in a public showcase for the community.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

A mix of spaces including an outdoor food court, a signature fountain plaza and areas for merchant carts, demanded a selection of materials that would provide variety for the large number of pedestrian and vehicular users. Clay pavers in six colors were chosen for the hardscape, which perfectly complements the earthy, natural palette of native and water-efficient plants, relocated oaks and seasonal color trees. A surprising array of patterns, blends of paver colors, and details also were used to further animate the ground plane and create a more human scale.

The clay pavers primarily were installed in a system that included sand joints and a sand setting bed over an aggregate base that allows infiltration of rainwater and reduces the stormwater runoff from the large pavement area; a sustainable feature that extended the link between hardscape and softscape. A more robust secondary system, which included a concrete base, was used in areas that provide access to emergency vehicles.

Clay paver system used at Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Crossings at Corona

Photos courtesy of NUVIS.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

The landscape architect for this project was NUVIS. Pacific Clay Products supplied the brick.

Finding balance was a high design priority for the landscape design of the Crossings at Corona, a 113-acre regional retail center in Corona, Calif. A key element in meeting this challenge was providing a hardscape that not only evokes a comfortable and natural environment in a suburban entertainment/lifestyle complex, but also incorporates sustainable design principles in a public showcase for the community.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

A mix of spaces including an outdoor food court, a signature fountain plaza and areas for merchant carts, demanded a selection of materials that would provide variety for the large number of pedestrian and vehicular users. Clay pavers in six colors were chosen for the hardscape, which perfectly complements the earthy, natural palette of native and water-efficient plants, relocated oaks and seasonal color trees. A surprising array of patterns, blends of paver colors, and details also were used to further animate the ground plane and create a more human scale.

The clay pavers primarily were installed in a system that included sand joints and a sand setting bed over an aggregate base that allows infiltration of rainwater and reduces the stormwater runoff from the large pavement area; a sustainable feature that extended the link between hardscape and softscape. A more robust secondary system, which included a concrete base, was used in areas that provide access to emergency vehicles.

Clay paver system used at Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Crossings at Corona

Photos courtesy of NUVIS.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

The landscape architect for this project was NUVIS. Pacific Clay Products supplied the brick.

Finding balance was a high design priority for the landscape design of the Crossings at Corona, a 113-acre regional retail center in Corona, Calif. A key element in meeting this challenge was providing a hardscape that not only evokes a comfortable and natural environment in a suburban entertainment/lifestyle complex, but also incorporates sustainable design principles in a public showcase for the community.

Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

A mix of spaces including an outdoor food court, a signature fountain plaza and areas for merchant carts, demanded a selection of materials that would provide variety for the large number of pedestrian and vehicular users. Clay pavers in six colors were chosen for the hardscape, which perfectly complements the earthy, natural palette of native and water-efficient plants, relocated oaks and seasonal color trees. A surprising array of patterns, blends of paver colors, and details also were used to further animate the ground plane and create a more human scale.

The clay pavers primarily were installed in a system that included sand joints and a sand setting bed over an aggregate base that allows infiltration of rainwater and reduces the stormwater runoff from the large pavement area; a sustainable feature that extended the link between hardscape and softscape. A more robust secondary system, which included a concrete base, was used in areas that provide access to emergency vehicles.

Clay paver system used at Crossings at Corona, a 113-acre regional retail center in Corona, Calif.

Save

Save

Are Your Employees Safe While Working In Hot Weather?

As the temperatures rise outside during summer months, so do the risks that employees working in hot conditions may be harmed by the dangerous effects it can have. Exposure to high temperatures can be deadly.1 It’s your responsibility as a business owner

Maximizing Efficiency with CrewTracks

In the masonry industry, efficient project management is crucial for success. CrewTracks addresses this need by streamlining various aspects of daily operations.

SOLA Innovation: Digital Levels

In 2021, SOLA introduced a new generation of digital levels at the World of Concrete. Because it was in the midst of Covid it wasn’t the most well-attended show, but we were optimistic. We attended, showcasing both our SOLA and Keson brands. The standout

Bonding with Masonry 2024 Q2

This issue’s questions come from an Architect, an Engineer. and a Mason Contractor. What questions do you have? Send them to info@masonrymagazine.com, attention Technical Talk.