Masonry Magazine December 1989 Page. 32
Cores
Cores are only found in brick manufactured with cores. Cores are only found in brick manufactured by the extrusion or dry-press process. Limits to the amount of coring allowed in brick, the distance from a core to a face, and web thickness where applicable are listed in Table 8.
Cells are similar to cores except that a cell is larger in cross-section than a core. Some requirements for cells are shown in Table 8. Additional requirements for cells can be found in ASTM C 652 and C 126.
Frogs
Frogs are depressions in brick usually located on one bed surface and are included for the same reasons as cores. Frogs are found in brick manufactured by the molded process. Panel frogs are limited to a specified depth and a specified distance from a face. Requirements for panel frogs are listed in Table 8. Deep frogs are frogs that are deeper than 3/8" (10 mm) deep, and must conform to the requirements for coring, hollow spaces and void area of the applicable standard.
ADDITIONAL REQUIREMENTS
Paving Brick, ASTM C 902
Not only must paving brick conform to the physical requirements in Table 4, but they must meet additional requirements for abrasion resistance or alternate performance requirements.
Alternate Performance Requirements. If information on the performance of units in an application of similar exposure and similar traffic is given, then the physical requirements in Table 4 may be waived.
Paving brick manufactured by the molded process have different physical requirements. See Table 3.
An optional test for the freeze and thaw test is ASTM C 88 Test Method for Soundness of Aggregates by Use of Sodium Sulfate. The sulfate soundness test, like the freeze/thaw test is not required, and the requirements apply only if the paving units do not meet the saturation coefficient and absorption requirements.
Abrasion Requirements. Since paving brick are used in a horizontal application and are exposed to traffic, brick must meet a specified abrasion limit. Paving brick are assigned a type by the traffic or abrasion expected. Type I pavers are exposed to extensive abrasion, such as driveways or public entries. Type II pavers are exposed to high levels of pedestrian traffic, such as in stores, restaurant floors or exterior walkways. Type III pavers, are exposed to pedestrian traffic, such as floors or patios in homes.
The abrasion resistance can be determined in either of two ways: 1) an abrasion index is calculated by dividing the absorption by the compressive strength and multiplying by 100, or 2) by determining the volume abrasion loss in accordance with ASTM C 418 Test Method for Abrasion Resistance of Concrete by Sandblasting. The abrasion requirements for Type I, II, and III are listed in Table 9.
TABLE 9
Abrasion Requirements
| Traffic Type | Abrasion Index (Max) | Volume Abrasion Loss (Max) (cm³/cm²) |
| --- | --- | --- |
| Type I | 0.11 | 1.7 |
| Type II | 0.25 | 2.7 |
| Type III | 0.50 | 4.0 |
Ceramic Glazed Brick, ASTM C 126
Since this specification is for ceramic glazed brick and tile, there are requirements for properties of the finish. These are imperviousness, opacity, resistance to fading, resistance to crazing, flame spread, fuel contribution and smoke density, toxic fumes, hardness and abrasion resistance. Requirements for each of these are included in the specification.
SUMMARY
This Technical Notes describes the classification of brick and the specific requirements found in ASTM standard specifications. It attempts to clarify some of the wording in ASTM specifications, although an official interpretation from ASTM must be received from the appropriate subcommittee. Problems and confusion can be eliminated if a basic understanding of the ASTM specifications is known.
The information and suggestions contained in this Technical Notes are based on the available data and the experience of the technical staff of the Brick Institute of America. The information contained herein should be used with good technical judgment and an understanding of the properties of brick masonry. Final decisions on the use of the information discussed in this Technical Notes are not within the purview of the Brick Institute of America and must rest with the project designer, owner or both.
REFERENCES
More detailed information on subjects discussed here can be found in the following publications:
1. ASTM Standard Specifications for Brick, Mortar and Applicable Testing Methods for Units. Reprinted by the Brick Institute of America.
2. ASTM C 88 Test Method for Soundness of Aggregates by Use of Sodium Sulfate. Annual Book of ASTM Standards, Volume 04.02.
3. ASTM C 418 Test Method for Abrasion Resistance of Concrete by Sandblasting. Annual Book of ASTM Standards, Volume 04.02.
4. Technical Notes on Brick Construction 9B, "Manufacturing, Classification and Selection of Brick Selection Part III", January 1989.