Masonry Magazine February 1992 Page. 14
Minimum compressive strength requirements are 600 lbs. per sq. inch based on net cross-sectional area.
Calcium Silicate Face Brick, ASTM C73-85 (89)
ASTM C73 covers brick made from sand and lime. Two grades are covered as follows: Grade SW - Brick intended for use where exposed to temperatures below freezing in the presence of moisture. Grade NW - Brick intended for use where exposed to temperature below freezing but unlikely to be saturated with water. Physical properties required by this specification are as follows:
TABLE 5-Physical Requirements for Calcium Silicate Brick, ASTM C73-85
| Designation | Compressive Strength min, psi (MPa), (brick tested flatwise) average gross area | Water Absorption max.lb/ft.3 (kg/m3) |
|---|---|---|
| | Average of 3 Brick | Individual Brick | |
| Grade SW | 4500 (31.0) | 3500 (24.1) | 10 (160) |
| Grade MW | 2500 (17.3) | 2000 (13.8) | 13 (208) |
Prefaced Concrete Masonry Units, ASTM C744
Specification C744, for Prefaced Units, is a specification for the facing materials applied to the surface of the masonry units. For the concrete masonry units onto which the prefaced surface is molded, C744 references the requirements contained in specifications C90, C55, and C129. Facing requirements in C744 include:
| Resistance to Crazing | Surface Burning Characteristics |
|---|---|
| Adhesion | Color Permanence |
| Chemical Resistance | Cleansability |
| Abrasion | Dimensional Tolerances |
This specification includes both limits and test procedures for these requirements.
Units for Construction of Catch Basins and Manholes
Specification C139 covers solid precast segmental concrete masonry units intended for use in the construction of catch basins and manholes. Units are required to be not less than 5 inches in thickness and must have minimum compressive strength averaging 2500 psi, and maximum water absorption of 10 lbs. of water per cubic foot of concrete.
References
1. "Concrete Masonry Standards", Authorized reprint of ASTM Standard Specifications and UBC Standards and Test Methods, TR-95A, National Concrete Masonry Association, 1991.
2. ASTM C90-90, "Standard Specification for Load-Bearing Concrete Masonry Units".
3. ASTM C140-90, "Standard Methods of Sampling and Testing Concrete Masonry Units".
4. ASTM C55-85, "Standard Specifications for Concrete Building Brick".
5. ASTM C139-73, "Standard Specification for Concrete Masonry Units for Construction of Catch Basins and Manholes".
6. ASTM C73-85, "Standard Specification for Calcium Silicate Face Brick (Sand-Lime Brick)".
7. ASTM C426-70 (Reapproved 1988), "Standard Test Method for Drying Shrinkage of Concrete Block".
8. ACI 530/ASCE 5, "Building Code Requirements for Masonry Structures".
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