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A Brief History of Pavers in North America
Face Mix Technology Updated for Unilock Series 3000



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In Mansfield Town Square, which is part of the Storrs Center development in Mansfield, Conn., a mix of gray, white and charcoal Unilock permeable and Series 3000 pavers were installed around a circular lawn. Read about the project at http://www.landscapeonline.com/research/article-a.php?number=28202.


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When concrete pavers were first introduced to North America, the only color choice was natural gray. Of course pavers are now available in a variety of colors that are produced when synthetic iron oxides are added to concrete. Different cements can also impact the color produced, creating some regional differences.


Concrete pavers were introduced to North America in the 1970s. The pavers were produced in Barrie, Ontario, Canada, and at that time, natural-colored (gray) pavers were the only available option. These pavers were all made with a standard finish, i.e., a concrete mix using a combination of large and small aggregates from the top to the bottom. As the pavers aged, concrete and pigment on the surface wore away, which made the pavers appear faded because more of the large aggregates were exposed.

The combination of coarse and fine aggregates in a concrete mix design is vital to achieve high strength, a low absorption rate, and good surface textures. Only with the proper blending and balancing of fine and coarse aggregates can a top-quality product be produced.

Cement acts as the "glue" within the mix, bonding together particles of coarse and fine aggregate. Mix designs, which call for a large amount of fine material, require more cement to coat each aggregate particle compared to the amount of cement needed for a mix of larger aggregate particles. The more cement used in the mix, the more expensive the product becomes. Finding the right balance is key to producing quality material at a good price.

Cement can be partially replaced with other materials, which are known as supplementary cementitious material (SCM). These materials may include:
• Fly ashes type C and F--residue from combustion of pulverized coal.
• Silica fume--residue resulting from the production of silica.
• Slag cement--ground granulated blast furnace (GGBF) slag, formed by rapidly chilling molten blast furnace slag.
• Natural pozzolans--materials that, when finely divided, will react chemically with calcium hydroxide in the presence of water to participate in a cementitious reaction.

The use of supplementary materials decreases the environmental impact associated with concrete production by reducing energy requirements and CO2 emissions.

Today, pavers are available in a wide palette of colors to complement almost any design vision. Some manufacturers use synthetic iron oxides (pigments) to tint concrete. A smaller particle size in the batch allows for higher strength tinting, lower loading, and cost savings. Even when the same pigments are used, product color can vary based on the source of the aggregates used in the concrete mix. Different regions or quarries produce different aggregates, which can have a significant effect on the color of the finished product. Different cements also impact the concrete color. This is important to keep in mind when working with suppliers with multiple manufacturing facilities.

Face mix paver technology was introduced in the early 1990s. These products are made with a top layer of specialized concrete mix representing approximately 12 percent of the total depth of the product. This layer--made up of either normal fine aggregates or a blend of high-quality minerals and aggregates--has a higher cement content and reduced water absorption. Larger aggregates are used in the base mix to give the paver strength. Face mix technology produces a more durable product with long-lasting color.

Taking this process one step further, Unilock added a special blend of granite and quartz to the top mix (or face mix) to create Series 3000, one of the most durable and most beautiful pavers on the market. Introduced to the market in 1993, it was like no other at the time.

Over the past 24 years, this product has proven to be one of the most durable. Its finish only gets better as it ages. The aggregates polish as they weather and twinkle when the sun hits them just right.

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Case Study: Navy Pier - Chicago Chicago's historic Navy Pier completed phase 1 of its reimagination to celebrate their 100th anniversary in 2016. The 50 acres of urban lakefront is a spectacular global destination and new model of sustainability.

Designed by landscape architecture firm James Corner Field Operations, the concept plan called for a complete transformation of Navy Pier's outdoor landscape into a more vibrant setting for recreation and social life. A more open and tree-lined South Dock Promenade (http://www.landscapeonline.com/research/article-a.php?number=27514), as well as an expansive and newly developed Polk Bros. Park and Fountain, were created.

Unilock worked with JCFO to create a custom group of products to fulfill their vision. The Series 3000 finish utilized a custom mix of aggregates including granite, quartz and a recycled copper slag to create the unique salt and pepper aesthetic. The use of 30 percent recycled content helped Navy Pier achieve Sustainable SITES Initiative (SITES) Gold Certification.

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Case Study: The Park at Lakeshore East - Chicago The Park at Lakeshore East is the central amenity at the 28-acre Lakeshore East master-planned community in Chicago's Inner Loop. Designed not only with the user in mind but for those who have a view of the park from above, the paths and walkways were inspired by sails from the boats that can be seen on nearby Lake Michigan. The paths use a minimalist arrangement of white and black Series 3000 pavers that serve as the primary circulation across the site.







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Last Updated 09-21-17
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