The unlimited design possibilities of interlocking concrete pave stones combined with their strength have provided Landscape Architects with an increasingly popular paving alternative. The vast array of shapes, textures and colors of interlocking concrete pave stones afford the opportunity to achieve aesthetically appealing paving designs. The interlocking method allows the pave stones to be used in pedestrian or vehicular paving structures previously only served by traditional paving methods. The term interlock refers to three kinds of load transfer in the segmental concrete pave stones: vertical interlock, horizontal interlock and rotational interlock. The sand installed between pave stone joints allows for the shear transfer of loads to the surrounding pave stones creating a vertical interlock. Laying patterns disperse forces created by the accelerations and breaking of vehicles for a horizontal interlock. Rotational interlock is achieved by the pave stone thickness and stationary edge restraint such as a curb. As a result of the interlock strength and capabilities, concrete pave stones can be used for a variety of applications for residential, commercial and industrial applications. Joey Guedea, Pavestone Company Dallas/Ft. Worth, explained the features and benefits of concrete interlocking pave stones as a streestcape paving material: ?EUR??,,????'??The design and pattern possibilities are truly limited only by the imagination of the landscape architect or designer. Pave stones are made from a ?EUR??,,????'??no slump?EUR??,,????'?? concrete mix and manufactured under extreme pressure and high frequency vibrations. Most pave stones have an average compressive strength greater than 8000 psi, an average water absorption maximum of 5% and will meet or exceed ASTM C-936. This feature provides twice the wearing course over poured-in-place concrete which averages 3,000-3,500 psi. The addition of pigment to the mix allows for the creation of custom colors. The color is integral throughout the stone versus some paving methods which have a surface color or texture stamped only on the top. ?EUR??,,????'??The shape and dynamics of the mold create a variety of options. For example, many pave stones are available with a chamfered, or beveled edge. Others have a more straight defined edge. Some are tumbled to create a weathered, old world look. And still others come in a variety of sizes and shapes that modulate together to allow for a random mosaic installation pattern. The versatility of pave stones to be used in any environment, whether historical, modern or artistic has been key to the growth of their popularity in the U.S. Additionally, interlocking concrete pave stones are reusable. When repairs or additions to underground utilities are required, the pave stones can be pulled up, palletized neatly while the repairs are underway. Once completed, they can be replaced without creating an eye-sore. Also, because there is no curing required for pave stones, the street work can be done over night so that there is no business loss to area merchants or inconvenience to customers and area residents.?EUR??,,????'?? The custom design capabilities of concrete pave stones allow a town or city to create their own unique identity. They can be used in streetscape applications such as drives, intersections, sidewalks and plazas to tie together a development. Located north of Dallas, the city of Frisco has become one of the fastest growing cities in north Texas with a growth rate over 2000-2001 figures by 26.09 percent. The Frisco Bridges Project would be the first major development into the previously small community from the fast exploding neighboring city, Plano. At the time of the planned development, Frisco had not been much more than a small rural community. Then a commercial development boom in north Plano saw a significant growth with the headquarters of Electronic Data Systems, Frito Lay and JC Penney corporations. The economic development of neighboring Plano spilled over into Frisco which began growing at a rapid pace. This growth mandated the development of residential and commercial properties including two major shopping malls and a minor league baseball park. As the first major development, Frisco Bridges set the tone for much of the city's growth. The streetscape projects included streets, intersections, crosswalks and park sidewalks using approximately 120,000 square feet of concrete pave stones. ?EUR??,,????'??Originally the project specified clay paves,?EUR??,,????'?? Guedea explained. ?EUR??,,????'??Using the rectangular holland stone, we were able to achieve the desired original color in the Provencial smooth finish. Using interlocking concrete pave stones resulted in cost-savings of both product and installation time. The ease of installation is a key component of concrete pave stones. The stringent requirement of the Specification ASTM-C936 for dimensional tolerances require a space bar. This allows pave stones to be installed in a 20 ft stringline remaining on course. Clay pavers do not have the space bar which requires much more time and attention to detail in the installation phase to assure that the product is installed in a straight line.?EUR??,,????'?? While the area north of Dallas has been exploding with urban development in the past decade, the southern area near downtown had not enjoyed the same growth rate. However, in recent years, urban development has provided major improvements to the southern area of town providing opportunities for upscale living. The Park at Farmer's Market was the first multi-family residential complex south of downtown. The residential property provides an upscale living alternative to the lofts that had replaced abandoned industrial buildings. It was also designed as a main artery connecting two of Dallas more popular landmarks: the Dallas Farmers' Market and the eclectic arts and entertainment district, Deep Ellum. The residential property used 100,000 sf in interlocking pave stones for sidewalks, plazas, streets and drives. Clay pavers were originally specified for the project. However, the property owner working in conjunction with the City, were able to achieve the original project design and colors while shaving paving costs. The pave stone selected was the rectangular holland stone in the non-chamfered, fine texture finish. This product has a smoother appearance and a richer color. Custom colors were created to allow the developer to achieve the original color designed for the streetscape pavements. An 8cm Plaza square stone was selected for the streets for it's strength for vehicular traffic. An architectural paving slab was the product of choice for a streetscape in downtown Atlanta, Georgia. The city Landscape Architect wanted a pavement design that would provide aesthetic appeal, but not require additional maintenance needs and costs. The Hexagon shaped paving slab was selected for the 15,000 square feet project. The shape provided an attractive, subtle design to the streetscape while assuring underground utility maintenance ease. The upscale area of Atlanta near Buckhead, Tower Place has installed 175,000 sf of a patented designed concrete pave stone. The Symetry pave stone consists of two shapes that modulate together, an L-shaped stone and a square. Tower Place is a commercial, retail, and residential development that has paved areas including sidewalks, crosswalks, plazas, parking lots, and drives. One of the most aesthetically appealing elements of the landscape project are the sidewalks that meander throughout the property encircling fountains, life size statues of children at play, and sitting area benches. It creates a city within a city with an easy flow for pedestrian and vehicular traffic. The project developers originally considered stamped concrete, but were concerned about maintenance issues. The versatility of installation designs of the patented pave stone allowed the Landscape Architect to achieve the desired more formal, upscale look. Interlocking concrete pave stones can be used to create harmony or contrast in the architectural design. Two colors can be combined to create interest. Multiple colors and/or blends can be used to create added interest or festivity. Because shade variations may occur in the actual stone colors, it allows the manufactured paving stone to achieve more of a natural look. One more factor to the versatility of concrete pave stones is the choices in laying patterns. For example, the simple Holland stone, or rectangle shaped paving stone can be installed in a runner bond, herringbone, 90 degree herringbone or basket weave pattern. The variety of pave stone choices allow for the paving structure to complement or contrast the building fa??? 1/4 ade, site furnishings and lighting, for an overall aesthetically pleasing landscape design. Installation pattern options, color choices and texture selections illustrate the many possibilities available for the contractor looking for a fresh solution for paving alternatives. Logsdon is a Dallas-based writer and frequent contributor to Landscape Architect and Specifier News magazine.