Concrete Masonry Units (CMU)

A Concrete Masonry Unit (CMU) [US], concrete block, or breeze block [UK], cinder block [US], clinker block (if bottom ash or clinker is used as an aggregate) is a large rectangular brick used in construction. Concrete blocks are made from cast concrete, i.e. portland cement and aggregate, usually sand and fine gravel in the case of blocks. They are formed typically in the shape of two squares joined on one side to form a rectangle, with the insides of the squares hollow. This allows structures to be built in the traditional masonry style of overlapping rows, with the structure's weight carried by the "walls" of the blocks.

Manufacturing CMU to meet specifications

Building Codes stipulate material specifications that become manufacturing requirements. In particular, ASTM C 90 — Standard Specification for Loadbearing Concrete Masonry Units governs the manufacturing requirements for concrete block. It is the specification for loadbearing concrete masonry units. ...

Assuring CMU quality

Cement as a binding agent is a primary ingredient of concrete. Section 4 of ASTM C90 and C1372 specifies that cementitious materials should meet minimum requirements of ASTM C1157, C595, C150, or C150 modified. For quality purposes, such substances should be consistent in color and performance over time. The cementitious content of masonry mix designs varies by region, materials, equipment, and product type. Yet, for typical products, cement content (in percent by total aggregate weight) generally falls within the following ranges: Standard gray concrete masonry unit (CMU) — 9-10 percent, Architectural CMU (often split-face) — 11-12 percent, Segmental retaining wall (SRW) units — 11-14 percent (13-14 percent, freeze/ thaw applications) and Other concrete landscaping products — varies with performance requirements ...

NECMA honors CMU design of R.I. residence

The winner of the New England Concrete Masonry Association (NECMA) 2004 Design Award of Excellence is a suburban Providence, R.I., private residence designed by William Kite Architects, Inc., also of Providence. Serving as masonry contractor for the project was Silveira's Masonry Construction, Warwick, R.I. Judges noted the diverse use of block as bearing, veneer, and exterior and interior walls, in addition to a floor plan reinforcing the economy of block construction. ...

Proudfoot introduces acoustical CMU

Proudfoot Co., a Monroe, Conn.-based developer of acoustical correction, noise control and specialty concrete masonry units, has become the U.S. distributor for Sound Cell. The new architectural masonry unit has a skewed internal construction to focus and redirect reflected sound into a sound-absorbing cavity, diminishing room loudness. ...

CMU Information from Around the Web

What is a Concrete Block?

A concrete block is primarily used as a building material in the construction of walls. It is sometimes called a concrete masonry unit (CMU). A concrete block is one of several precast concrete products used in construction. Cavette, Chris. What is a Concrete Block? Retrieved from Answers.com at http://www.answers.com/topic/concrete-block...