A segmental retaining wall is a network of masonry units that rely largely upon their own mass for strength and stability. These concrete units are placed together without the use of mortar and typically employ some type of interlocking mechanism. Segmental retaining wall blocks may be solid or hollow with a gravel fill material. This retaining wall system requires no heavy equipment or curing time and can usually be constructed by one person. A segmental retaining wall can be used to form curves, steps, and terraces for both large and small scale projects.
Segmental retaining wall units are available in a wide variety of shapes, sizes, colors, and textures. The individual units typically interlock both horizontally and vertically to eliminate the need for mortar. These concrete units are typically solid but some manufacturers utilize a block with a hollow interior. The interior of hollow blocks is usually filled with gravel because each course is built to further enhance the wall's stability. A segmental retaining wall can be tilted backward toward the slope to further strengthen the structure.
The interlocking deign of a segmental retaining wall also eliminates the usual material and labor costs associated with this type of structure. There is typically no need for heavy equipment to remove and replace the existing base soil because a concrete footing is not required. The individual blocks are made of high strength concrete that resists freezing, crumbling, and abrasions. Unlike poured concrete structures, segmental systems remain somewhat flexible to prevent stress fractures.
The unique design of a segmental retaining wall allows it to be easily shaped in ways that would be difficult with other construction methods. Stairs, terraces, and intricate curves can be constructed with blocks of different sizes and shapes. The lightweight units can usually be lifted into place by only one person. The simple interlocking construction method can also typically be performed by individuals with no previous building experience. Because there is no mortar used in this retaining wall, it can be installed year-round in any climate.
This type of wall can also be utilized for larger scale applications such as building and highway construction. Bridge abutments, parking lot supports,and erosion control structures can be constructed with segmental walls. Strong retaining walls up to 30 feet (9.1 m) in height are possible with this construction method. Some type of professional engineering is usually required for most large-scale segmental retaining wall projects, however.