ASTM C55-23

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C55 − 22 C55 − 23
Standard Specification for
Concrete Building Brick
This standard is issued under the fixed designation C55; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This specification covers solid, dry-cast, concrete building brick intended for interior and exterior use in constructing structural
masonry, and are made from portland cement, water, and suitable mineral aggregates with or without the inclusion of other
materials.
NOTE 1—Specification C1634 addresses concrete facing brick used in facing applications and other exposures (previously referred to in earlier editions
of this standard as Grade N—for use as architectural veneer and facing units in exterior walls and for use where high-strength and resistance to moisture
penetration and severe frost action are desired). This specification differs from C1634 in that it addresses properties for concrete building brick used in
non-facing, utilitarian applications (previously referred to in earlier editions of this specification as Grade S—for general use where moderate strength
and resistance to frost action and moisture penetration are required).
1.2 The text of this specification references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
NOTE 2—Concrete building brick covered by this specification are made from lightweight or normal weight aggregates, or both.
NOTE 3—When particular features are desired, such as density classification, high compressive strength, surface textures for appearance or bond, finish,
color, fire resistance, insulation, acoustical properties, or other special features, such properties should be specified separately by the purchaser. Suppliers
should be consulted as to the availability of concrete building brick having the desired features.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C33/C33M Specification for Concrete Aggregates
C140/C140M Test Methods for Sampling and Testing Concrete Masonry Units and Related Units
This specification is under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.03 on
Concrete Masonry Units and Related Units.
Current edition approved Dec. 15, 2022Dec. 1, 2023. Published January 2023December 2023. Originally approved in 1924. Last previous edition approved in 20172022
as C55 – 17.C55 – 22. DOI: 10.1520/C0055-22.10.1520/C0055-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C55 − 23
C150/C150M Specification for Portland Cement
C331/C331M Specification for Lightweight Aggregates for Concrete Masonry Units
C426 Test Method for Linear Drying Shrinkage of Concrete Masonry Units
C595/C595M Specification for Blended Hydraulic Cements
C618 Specification for Coal Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C979/C979M Specification for Pigments for Integrally Colored Concrete
C989/C989M Specification for Slag Cement for Use in Concrete and Mortars
C1157/C1157M Performance Specification for Hydraulic Cement
C1232 Terminology for Masonry
C1240 Specification for Silica Fume Used in Cementitious Mixtures
C1634 Specification for Concrete Facing Brick and Other Concrete Masonry Facing Units
3. Terminology
3.1 Terminology defined in Terminology C1232 shall apply for this specification.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 concrete building brick, n—a concrete masonry unit, with a maximum width of four (4) inches and of a weight that will
typically permit it to be lifted and placed with one hand, that is manufactured for general use in non-facing, utilitarian applications.
3.2.2 concrete facing brick, n—a concrete masonry unit, with a maximum width of four (4) inches and of a weight that will
typically permit it to be lifted and placed with one hand, that is manufactured to be typically used in an application where one or
more faces of the unit is intended to be exposed.
4. Materials and Manufacture
4.1 Cementitious Materials—Materials Cementitious materials shall conform to the following applicable specifications:
4.1.1 Portland Cement—Specification C150/C150M.
4.1.2 Modified Portland Cement—Portland cement conforming to Specification C150/C150M, modified as follows:
(1) Limestone—If calcium carbonate is added to the cement, the CaCO content shall not be less than 85 %.
(2) Limitation on Insoluble Residue—1.5 %.
(3) Limitation on Air Content of Mortar—Volume percent, 22 % max.
(4) Limitation on Loss on Ignition—7 %.
4.1.3 Blended Hydraulic Cements—Specification C595/C595M.
4.1.4 Hydraulic Cement—Specification C1157/C1157M.
4.1.5 Pozzolans—Specification C618.
4.1.6 Blast Furnace Slag Cement—Specification C989/C989M.
4.1.7 Silica Fume—Specification C1240.
4.2 Aggregates—Aggregates shall conform to the following specifications, except for grading requirements:
4.2.1 Normal Weight Aggregates—Specification C33/C33M.
4.2.2 Lightweight Aggregates—Specification C331/C331M.
NOTE 4—The grading requirements of Specifications C33/C33M and C331/C331M may not be suitable for concrete masonry production. Because of this,
producers are allowed to modify grading to meet their needs and the requirements of this specification.
4.3 Pigments for Integrally Colored Concrete—Specification C979/C979M.
C55 − 23
4.4 Other Constituents—Air-entraining agents, integral water repellents, and other constituents shall be previously established as
suitable for use in concrete building brick and shall conform to applicable ASTM standards or shall be shown by test or experience
not to be detrimental to the durability of the concrete building brick or any material customarily used in masonry construction.
5. Physical Requirements
5.1 At the time of delivery to the purchaser, units shall conform to the physical requirements prescribed in Table 1. Units shall
be free of defects that significantly impair the strength or permanence of the construction.
5.1.1 When higher compressive strengths than those listed in Table 1 are specified, the tested average net area compressive
strength of three units shall equal or exceed the specified compressive strength, and the following single unit strength requirements
shall apply.
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