Masonry: Encyclopedia II - Masonry - Concrete block

Masonry - Concrete block

Blocks of cinder concrete ("cinder blocks" or "breezeblocks"), ordinary concrete ("concrete blocks"), or hollow tile are generically known as "CMUs," or Concrete Masonry Units. They are usually much larger than ordinary bricks and so are much faster to lay for a wall of a given size. Furthermore, cinder and tile blocks have much lower water absorption rates than brick masonry. They are often used as the structural core for veneered brick masonry, or are used alone for the walls of factories, garages, and other "industrial" buildings where appearance is not a significant factor. Such blocks often receive a stucco surface for decoration. Surface-bonding cement is sometimes used in this application and can impart extra strength to a block wall.

The primary advantage of concrete blocks in comparison to smaller clay-based bricks is that a CMU structure can be reinforced by either fully-grouting the voids or inserting vertical lengths of rebar and using grout to hold them in place. In this manner, a CMU wall can be constructed to be much stronger than typical masonry walls.

Some concrete blocks are colored, and some employ a "break face", which allows the reproduction of an appearance similar to quarried stone, such as brownstone. For applications such as roadway sound control walls the patterns may be complex and even artistic.

Adapted from the Wikipedia article "Concrete block", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki