The common misconception about the topic of paving is that it is exclusively used for parking lots. In this section, two new concepts are introduced that redefine the way in which paving is viewed. The two major sections stimulate and promote thinking about the exterior horizontal surfaces in a non-traditional way and presents diagrams and illustrations that integrate the use of precast concrete pavers into the design of the built environment. Portion of Harfmann/Day publication 

The issue of scale is a common concern when designing the large exterior surfaces of the urban carpet. Large monolithically paved surfaces do not tend to provide the human with any dimensional relationship to the environment on which their feet are planted. The use of segmental paving, by default, offers a direct dimensional relationship between the human and the individual units that make up the paved assembly. 
Portion of Harfmann/Day publication 

Although concrete pavers can be more expensive initially than asphalt or reinforced concrete, it is important to consider the cost relative to the life cycle of the pavement as well. The initial costs for materials and installation and the life cycle costs are considered direct costs and are easily quantifiable. There are however, external costs that are not as easily quantifiable but must be considered when determining pavement options. These costs include environmental impact, road user costs during repairs, integration of other requirements, redesign, pavement rehabilitation and aesthetics. The segmental and precast nature of the concrete paving units capitalize on several of these aspects while reducing lifecycle costs.
Portion of Harfmann/Day publication - Other advantages include: Design Variety, Safety, Zip and Unzip, and Environmental Impact. 

The indivual units of interlocking concrete pavements support the concept of a "zipper" which can be undone and then redone in a simple manner. Since the pavers are interlocked and not permanently attached to one another, it is possible to remove several individual units and simply replace them once a repair is made. The final result is undetectable and inexpensive. It is an immediate response to the need to gain access to the surface below or for the repair of damaged areas of the surface. 
Portion of Harfmann/Day publication - Other advantages include: Design Variety, Safety, Environmental Impact, and Cost. 

Discover the competitive advantages of concrete pavers over other hardscape materials.  These advantages include: Design Variety, Environmental Impact, Safety, Zip and Unzip, and Cost.  See the full writeup by clicking Read More or select any of the linked words above to download the associated pdfs.
Portion of Harfmann/Day publication

This lesson introduces and then tests the viewer on the variables that must be considered when using segmental pavements to support pedestrian and vehicular loads on municipal streets. According to the American Society of Civil Engineers (ASCE), the following four variables are critical to consider:

An ESAL is a standard unit that is used to measure the amount of damage vehicles inflict on a surface. 1 ESAL = the impact from a single 18,000-lb axle load. The damage to a pavement caused by one pass of a large tractor-trailer in exponentially greater than that caused by a two door sedan.

It takes roughly 20,000 passes of the sedan to cause the same amount of same amount of damage as one pass of a tractor-trailer. In these scenarios, the design ESALs will be predetermined. This is usually based on the expected traffic mix. Reference ASCE and ICPI Tech Spec 4 to calculate the appropriate ESAL rating to a design.

Remember that when choosing a paver it is always important to consider the surrounding environment. Pavers that are a few shades lighter than any building or house on the property won't compete for attention. Brick-colored pavers add a warmth to wood or stone buildings, and gray-toned pavers are often paired with brick buildings to minimize over matching. Monotony of color can be broken up by using a blended-paver or combining two types of pavers. Whatever design effect is desired it can potentially  be achieved through the use of paver color.

Dimensional tolerances are important on a paver’s structural efficiency. Rectangular and shaped blocks need to be designed to include their surrounding space; and their length to width ratio depends upon the final laying pattern. To optimize the block surfacing structural efficiency then every block must be specified and controlled within strict tolerances.

Embodied Energy: "Comprises the energy consumed during the extraction and processing of raw materials, transportation of the original raw materials, manufacturing of building materials and components and energy use for various processes during the construction and demolition of the building."

Manufacturers of ICP are usually within a 500 mile radius of the site which can reduce the environmental costs of transportation.

Molds and pigments vary by region and factory.

Local sourcing allows for the use of aggregates from local sources.

This video demonstrates the flexing properties of interlocking concrete pavers. This flexing pattern allows for weight and pressure to be distributed evenly over the pavers, which as a result provides for a higher PSI (Pounds per Square Inch) and a material that is more durable than Asphalt or Poured Concrete. Interlocking pavers are proving to be a huge money saver with very little maintenance costs. The strength and durability of ICP can be seen in shipping ports, airports and other high density/heavy load areas.

The successful transferal of any vertical load through a segmental paved area requires the incorporation of three principles. These principles must be utilized when installing open grid as well as solid interlocking pavers. It is also important to note that all three principles are equally important.

Vertical loads are transferred through an assembly of units through the development shear between the units. When the units are placed next to each other in a tight arrangement, friction between the units is developed thereby mobilizing a large portion of the paved plane for load resistance. In order to develop the friction which develops the shear, the units must be continuous and contiguous within an arrangement. 

The Principle of Interlock:
Interlock is the inability of a paver to move independently from its neighbors. It is critical to the structural performance of interlocking concrete pavement. When considering design and construction, three types of interlock must be achieved: vertical, rotational, and horizontal interlock. These are illustrated in Figure 1.

Derek Kaplan discusses the role of patterning in contemporary design through the lens of Islamic architecture, "With this current resurgence of surface articulation comes a renewed value in revisiting historical examples from veins of architecture that have previously pursued this line of development, with Islamic architecture being particularly relevant due to its avoidance of representational iconography in favor of highly sophisticated geometry and pattern.  Read the article on archinect.

Learn about the materials that go into making a paver and how locally sourced materials can require less energy to manufacture. 

This PDF highlights how interlocking pavements were able to put soldiers back to work rebuilding cities.