The primary structural system must be concrete masonry. This can be single-wythe concrete masonry or multi-wythe, with the backup being CMU. Participants are encouraged to consider innovative ways to use concrete masonry products in interior, exterior, and landscape applications. Outdoor spaces can include concrete masonry (such as screen or privacy walls) as well as other dry-cast concrete products, such as concrete pavers and segmental retaining wall units.
Concrete Masonry Units (CMU)
CMU are manufactured using dry-cast concrete on high-speed manufacturing equipment. Dry-cast concrete differs from other types of concrete in that it is initially mixed to a very stiff consistency. This consistency facilitates production through manufacturing equipment. This equipment utilizes compaction and vibration to form the units, and a curing process to accelerate hardening.
There are several American Society for Testing and Materials (ASTM) specifications that cover concrete masonry products. The primary one is ASTM C90, Standard Specification for Loadbearing Concrete Masonry Units.
Additional Concrete Products
The manufacturing process for CMU is also used to make a variety of other types of products, including segmental retaining wall (SRW) and concrete paving units. These are primarily used in hardscape applications (residentially, commercially, and more).