ASTM C0270-25B
Standard Specification for Mortar for Unit Masonry
| Standard number: | ASTM C0270-25B |
| Released: | 01.12.2025 |
| Status: | Active |
| Pages: | 14 |
| Section: | 04.05 |
| Keywords: | air content; compressive strength; masonry; masonry cement; mortar; portland cement-lime; water retention; water retentivity; |
| ASTM number: | ASTM C270 |
| Supersedes: | C0270-25A |
This specification covers mortars for use in the construction of non-reinforced and reinforced unit masonry structures. Four types of mortar are covered in each of two alternative specifications: (1) proportion specifications and (2) property specifications. The property specification applies to mortar mixed to a specific flow in the laboratory. When neither proportion nor property specifications are specified, the proportion specifications shall govern, unless data are presented to and accepted by the specifier to show that mortar meets the requirements of the property specifications. This specification does not cover the determination of mortar strengths through field testing. The compressive strength values resulting from field tested mortars do not represent the compressive strength of mortar tested in the laboratory nor that of the mortar in the wall. Physical properties of field sampled mortar shall not be used to determine compliance to this specification and are not intended as criteria to determine the acceptance of rejection of the mortar. Compliance to this specification is verified by confirming that the materials used are as specified, meet the requirements as given, and added to the mixer in the proper proportions as described.
1.1 This specification covers mortars for use in the construction of non-reinforced and reinforced unit masonry structures. Four types of mortar are covered in each of two alternative specifications: (1) Proportion Specification and (2) Property Specification.
Note 1: When the Property Specification is used to qualify masonry mortars, the testing agency performing the test methods should be evaluated in accordance with Practice C1093.
1.2 The Proportion Specification or Property Specification shall govern as specified.
1.3 When neither the Proportion Specification or the Property Specification are specified, the Proportion Specification shall govern, unless data are presented to and accepted by the specifier to show that mortar meets the requirements of the Property Specification.
1.4 This standard is not a specification to determine mortar strengths through field testing (see Section 3).
1.5 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.
1.6 The terms used in this specification are identified in Terminologies C1180 and C1232.
1.7 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.
1.8 The following safety hazards caveat pertains only to the test methods section of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 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.