The use of concrete and brick paving units has increased tremendously in the last dozen years. SEGMENTAL PAVEMENT TYPES Paving units can be installed in a variety of ways, depending on the type of unit, the soil conditions on the site, and the traffic the pavement will have to bear. MORTARED PAVEMENTS Brick pavers sometimes are laid with mortared joints in a mortar bed over a rigid concrete base. This paving system is suitable for heavy traffic loads in cases where surface drainage is desirable, and when the units themselves show significant variation in dimension. It also is the type of paving most similar to traditional bricklaying and the one most often performed by skilled masons. MORTARLESS PAVEMENTS More commonly, both clay and concrete paving units are set without mortar in a sand bed over a well-compacted but flexible aggregate base. For this type of paving, proper layout, grading, and base preparation are paramount, and the actual placement of paving units is a fairly mechanical task.