Masonry Magazine August 1973 Page. 22
Rapid Assembly System
A number of rapid assembly or mortarless systems have come into use in the past 20 years. These are systems that are designed for assembly by unskilled or partially skilled tradesmen using methods that do not require the use of a trowel in the traditional manner but may require a grout or plaster. Some of the better known systems are these:
An interlocking system that makes use of tight-fitting keys or plugs that tie adjacent block together. After being laid up dry the wall may be permanently tied together by plastering the surfaces and, if desired, by grouting vertical steel in some of the cores.
A tongue-and-groove interlocking system that is assembled by laying block up dry and bonding them by grout that flows through vertical and horizontal channels. Steel may be utilized in the channels if desired.
Wedge-shaped block that tightly interlock with double-V grooves in both directions. These are self-plumbing and self-aligning. Joints are sealed against moisture penetration by beads of waterproof sealer.
TABLE 2
Typical Values
for Concrete
Masonry Walls
| Nominal Block Thickness, in. | Net Area, in.2 per ft. length | Volume, in.3 per ft. length | Wall weight, psf | Section Modulus, in.3 per ft. length | Moment of Inertia, in.4 |
|---|---|---|---|---|---|
| | | | 60 pcf(1) | 80 pcf(1) | 100 pcf(1) | 120 pcf(1) | 140 pcf(1) | | |
| 4 | 31.2 | 250 | 14 | 18 | 22 | 27 | 31 | 24 | 43 |
| 6 | 40.5 | 324 | 20 | 26 | 33 | 40 | 46 | 50 | 140 |
| 8 | 45.0 | 360 | 24 | 32 | 40 | 47 | 55 | 80 | 305 |
| 10 | 61.0 | 488 | 28 | 37 | 47 | 56 | 65 | 125 | 600 |
| 12 | 70.0 | 560 | 34 | 45 | 55 | 67 | 78 | 190 | 1105 |
(1) Unit weight of concrete in block
NATIONAL CONCRETE MASONRY ASSOCIATION
P.O. Box 9185, Rosslyn Station, Arlington, Virginia 22209