Horizontal bond beam reinforcement is easily accommodated in these units. Bond beam units are either manufactured with reduced webs or with “knock-out” webs, which are removed prior to unit placement in the wall.

Bond beams in concrete masonry walls can be accommodated either by saw-cutting a portion of the webs out of a standard unit, or by using bond beam units. This eliminates the need to lift units over the top of the reinforcing bar, or to thread the reinforcement through the masonry cores after the wall is constructed. Open-ended units allow the units to be threaded around reinforcing bars. The taper provides a wider surface for mortar and easier handling for the mason. Depending on the core molds used in the manufacture of the units, face shells and webs may be tapered with a flare at one end, or may have a straight taper from top to bottom. Typically, the face shells and webs are tapered on concrete masonry units. Some common unit configurations are shown in Figure 2. Concrete brick may be 100% solid or cored, provided that the cored area of the brick does not exceed 25% of the gross cross-sectional area.Ĭoncrete masonry unit shapes have been developed for a wide variety of applications. 2), are available in a wide array of nominal lengths and heights typically with a nominal 4 in. In addition to the unit sizes above, concrete brick complying with ASTM C1634, Standard Specification for Concrete Facing Brick (ref. The net cross-sectional area of a solid unit is at least 75% of the gross cross-sectional area. ASTM C90 also defines the difference between hollow and solid concrete masonry units. Where required, units may be manufactured to closer tolerances than those stipulated by ASTM C90.

Overall unit dimensions (width, height, and length) are permitted to vary by ± 3/8 in. ASTM C90 includes minimum face shell and web thicknesses for the different sizes of concrete masonry units as listed in Table 1. 1) is the most frequently referenced standard for concrete masonry units. Standard Specification for Loadbearing Concrete Masonry Units, ASTM C90 (ref. In addition to these standard sizes, other unit heights, lengths, and thicknesses may be available from local concrete masonry producers. (203 x 203 x 406 mm) concrete masonry unit. Figure 1 illustrates nominal and specified dimensions for a nominal 8 x 8 x 16 in. (102 3 or 203 mm) module is maintained with 3/8 in. (9.5 mm) less than nominal dimensions, so that a 4 or 8 in.

Specified 3 dimensions of concrete masonry units are typically 3/8 in. Nominal dimensions refer to the module size for planning bond patterns and modular layout with respect to door and window openings. (406 mm), available in nominal thicknesses of 4, 6, 8, 10, 12, 14, and 16 in. Typically, concrete masonry units have nominal face dimensions of 8 in.

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