Masonry Magazine December 1992 Page. 24
Coarse Sand and Flexible Base Pavements
Applications for flexible bases range from residential patios to city streets. Flexible paving systems are typically the most economical to install since less labor and fewer materials are involved. The thickness of each layer in a flexible pavement depends upon the imposed loads and the properties of each layer. A pavement subjected to heavy vehicular traffic requires a thicker base than a pavement subjected to pedestrian traffic.
Figure 1 is a typical section through a flexible brick pavement. Brick pavers are set in a 1 in. to 1½ in. (25 to 38 mm) sand setting bed over a compacted base, subbase (if necessary) and compacted subgrade. Many commercial pedestrian and vehicular applications can use this type of assembly. Pavements subjected to vehicular traffic must be designed to accommodate the wheel loads. The Flexible Brick Pavements design guide covers design and installation requirements for heavy vehicular loading.
Semi-Rigid Base Pavements
Asphalt bases are classified as semi-rigid bases. Only mortarless brick paving is suitable over this type of base. Figure 3 is an example of an asphalt base and an asphalt setting bed supporting the mortarless brick paving. The mortarless brick paving and asphalt setting bed can also be laid on a concrete base. These assemblies are suitable for medium to heavy vehicular traffic, pedestrian malls or other pedestrian areas.
Residential Pedestrian Applications
In residential pedestrian applications, the detail in Fig. 2 can be used. The brick pavers are laid directly on the compacted sand and subgrade. This application works best when the subgrade is compacted or on undisturbed earth, and where frost heave is not a consideration. A geotextile can be used beneath the sand base where the soil conditions are poor.
Paving Assembly on a Semi-Rigid Base
The detail shown in Fig. 4 is another paving assembly on a semi-rigid base. Two layers of No. 15 building felt or one layer of No. 30 felt act as a cushion between the brick pavers and the base and help accommodate size variations. This detail is only suitable for residential pedestrian applications.