1.1 本规范涵盖材料和设计要求受本规范管辖的砌筑砂浆 C270 而是在工厂中预混合干燥，而不是由运送到工地的单个原材料生产。 1.2 现场取样、测试、直接可比测试结果、包装以及预混合干砂浆混合物成分的可追溯性与现场混合砂浆不同，本标准专门解决了这些问题。还包括对预混合干砂浆可能的成分比例的严格控制。 1.3 本规范的文本指的是注释和脚注，它们提供了解释性材料。这些注释和脚注（不包括表和图中的注释和脚注）不应被视为本标准的要求。 1.4 以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值合并可能导致不符合标准。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。( 警告-- 新鲜的水硬性水泥混合物具有腐蚀性，长时间暴露可能会对皮肤和组织造成化学灼伤。 ) 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。

1.1 This specification covers masonry mortars whose materials and design requirements are governed by Specification C270 but are preblended dry in a factory instead of produced from individual raw materials delivered to the job-site. 1.2 The field-sampling, testing, directly comparable test results, packaging, and the traceability of ingredients of preblended dry mortar mix differ from job site mixed mortars and this standard specifically addresses these issues. The tight control of ingredient ratios possible with preblended dry mortar is also covered. 1.3 The text of this specification refers to notes and footnotes, which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered the requirements of the standard. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 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. ( Warning— Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. ) 1.6 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.