The Evolution and Innovation of Concrete Unit Pavers

Words: Brandi Sauers
Photos: Hanover Architectural Products, Inc.

When concrete unit pavers were first produced in Europe after the second World War, they were used as a replacement for clay brick pavers due to a lack of raw materials needed to produce that product. The primary emphasis was function with little to no concern regarding aesthetic value. The original products were fabricated in plain concrete color and a small brick shape format. Today, we see concrete unit pavers available in various shapes and sizes ranging from smaller brick units to larger paver units. The variety of colors and textures available are limitless to align with the intended design. Styles range from rustic to traditional to modern or contemporary.

Concrete pavers are composed of sand, stone, and Portland cement as a binder. Colors can be achieved through various combinations of white or grey cement, pigments, and various colored aggregates. After production, the top surface is smooth with a solid or blended color. Textures can then be applied through special processes to reveal aggregate materials beneath the surface. Texturizing creates many different unique appearances and can alter the appearance of the original/pre-texturized color. Manufacturers, such as Hanover®, with access to a diverse aggregate sources have the ability to provide an extensive color palette.

Those considering the use of concrete unit pavers should be familiar with the physical properties of the material, such as density, compressive strength, flexural strength, absorption rate, resistance to freeze/thaw, coefficient of friction, and abrasion resistance.

To ensure efficient installation, pavers should be fabricated to close tolerances regardinglength & width (+/- 1/16") and thickness (+/- 1/8") which are generally considered to be industry standards. Hanover® can "gauge" pavers for thickness to achieve a tighter tolerance of 1/32" to 1/16" tolerance. This process is achieved by running each paver through a grinder, similar to using a planer for woodworking. This is extremely beneficial when pavers are installed on a semi-rigid medium which will not allow fine elevation adjustments. Paver applications have grown beyond on-grade applications to include pedestal sets over waterproofed decks and vertical applications that incorporate standard masonry practices.

Setting Beds
The concrete paver industry has traditionally set pavers in one of 2 options: Rigid or Flexible systems. Let's first address on-grade installations.

Mortar Set - Rigid Set
A rigid system will incorporate mortar in thin-set or thick-bed applications.
This method will bond the setting bed to a concrete substrate and the pavers to the setting bed. Using latex additive admixture to the mortar is recommended because the bond and shear strength are enhanced using just a sand/cement mixture. Remember that a fully bonded/rigid system is being created, and expansion joints should be utilized per the current standard masonry construction method. The expansion joints will need to be extended up to the surface of the pavers.

Sand-Setting Bed - Flexible Set
A flexible paving system can be achieved with either sand or bituminous setting beds.
Keep in mind that the only function of the setting bed in this instance is to provide a
leveling course for the pavers. Stability and load-bearing capability are achieved in the
correct sub-base construction, which will aid in load distribution.

Sand conforming to ASTM C-33 should be loosely screened to a depth of 3/4" - 1" over the properly prepared sub-base. Pavers ranging in size from 12" x 12" and smaller can be tamped level with a vibratory plate compactor. Filling the joints with the sand can create a true interlocking system with proper edge restraints.

Bituminous Setting Bed
While still considered a flexible setting system, the combination of ASTM C-33 sands and
hot bituminous material provides a stable leveling course, eliminating the potential for movement or migration of the setting bed material. This movement can occur when larger format pavers are used in sand-only setting beds. Professionally installed, this system can offer a long-term maintenance-free solution.

PEDESTAL SET PAVERS OVER WATERPROOFING
Over the years, concrete pavers have been proven to be a beneficial addition to roofing/waterproofing systems. Maximining once unusable space on buildings, pavers set on pedestals offer greater use of space and an excellent gathering space enhancing our daily interactions.

Larger format pavers can be installed over waterproofing membranes on pedestals to create plaza decks and amenity spaces. Pedestal set pavers can allow a level paved surface over a sloped substrate to drain. Pavers are loosely laid over the pedestals, which can be adjusted to the correct height. Because the pavers are loose-laid, they can be easily removed and replaced without showing any signs of disturbance.

VERTICAL WALL PANELS AND MASONRY
Concrete units can also be utilized for vertical applications. Large format units can be manufactured to accommodate a clipping system similar to a natural stone veneer. Masonry units with a standard bed depth of 3 5/8" or greater can also be achieved, along with capabilities for color-coordinating sills and water tables. Hanover’s newest innovation has led to the production of vertical Modular and Utility concrete bricks that offer the industry vast color and texture options that were once limited.

Through market demand and innovation, the concrete unit paving industry grew vastly from its origins, which were born out of necessity. As trends and tastes evolve, concrete unit pavers and vertical materials will continue to work to satisfy the marketplace's demands.

The Evolution and Innovation of Concrete Unit Pavers

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