1.1 本试验方法包括获取、制备和测试从混凝土中钻取的芯样，以确定长度或抗压强度或劈裂抗拉强度。本试验方法不适用于喷射混凝土芯。 注1: 试验方法 C1604/C1604M 适用于从喷射混凝土中获取、制备和测试芯样。 注2: 附录X1 提供获取和测试锯梁弯曲性能的建议。 1.2 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.3 本标准的文本引用了提供解释材料的注释和脚注。这些注释和脚注（不包括表和图中的注释和脚注）不应视为本标准的要求。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 3.1 本试验方法提供了获取和测试样本的标准程序，以确定现浇混凝土的抗压强度、劈裂抗拉强度和弯曲强度。 3.2 通常，当对试验结果存在疑问时，可获得试样- 由于施工期间强度测试结果较低或结构有损坏迹象，浇筑混凝土质量较差。该方法的另一个用途是提供旧结构的强度信息。 3.3 混凝土强度受混凝土在结构构件中的位置影响，底部的混凝土比顶部的混凝土更坚固。芯强度还受相对于浇筑混凝土水平面的芯方向的影响，当平行于水平面测量时，强度趋于较低。 3. 在规划获取混凝土样品的位置和比较强度试验结果时，应考虑这些因素。 3.4 通过芯样试验测量的混凝土强度受试验时试样中水分的数量和分布的影响。没有标准程序来调节样本，以确保在测试时，其与结构中的混凝土处于相同的水分条件。 本试验方法中的水分调节程序旨在提供可重复的水分条件，以尽量减少实验室内和实验室之间的变化，并减少样品制备过程中引入的水分的影响。 3.5 芯的测量抗压强度通常低于在相同年龄测试的相应适当成型和固化标准圆柱体的抗压强度。然而，对于给定的混凝土，这两种试样的强度之间没有唯一的关系（见 附注3 ). 这种关系受到许多因素的影响，例如混凝土的强度水平、现场温度和湿度历史、固结度、批次间的可变性、混凝土的强度增益特性、取芯装置的条件以及取芯时的注意事项。 注3: 有一种程序可用于根据测得的堆芯强度估算等效圆柱体强度。 4. 注4: 在适用建筑规范或其他可能管辖项目的合同或法律文件中没有核心强度要求的情况下，测试的指定人应在项目规范中制定核心强度的验收标准。ACI 318中提供了岩芯强度验收标准的示例， 5. 用于评估在施工期间为调查标准固化圆柱体的低强度试验结果而取的芯样。根据ACI 318，如果三个混凝土芯的平均强度至少为85，则认为混凝土芯代表的混凝土在结构上足够 % 且任何单芯强度均不低于75 % 具有规定的强度。 3.6 本测试方法中引用的“测试规范者”是负责分析或审查和验收核心测试结果的个人。 注5: 对于低强度试验结果的调查，ACI 318-14将试验的指定人定义为获得许可的专业设计人员或建筑官员。 3.7 由芯测量的混凝土表观抗压强度受测试芯的长径比（L/D）的影响，在制备芯样和评估测试结果时必须考虑这一点。

1.1 This test method covers obtaining, preparing, and testing cores drilled from concrete for length or compressive strength or splitting tensile strength determinations. This test method is not applicable to cores from shotcrete. Note 1: Test Method C1604/C1604M is applicable for obtaining, preparing, and testing cores from shotcrete. Note 2: Appendix X1 provides recommendations for obtaining and testing sawed beams for flexural performance. 1.2 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. 1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 1.4 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. 1.5 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. ====== Significance And Use ====== 3.1 This test method provides standardized procedures for obtaining and testing specimens to determine the compressive, splitting tensile, and flexural strength of in-place concrete. 3.2 Generally, test specimens are obtained when doubt exists about the in-place concrete quality due either to low strength test results during construction or signs of distress in the structure. Another use of this method is to provide strength information on older structures. 3.3 Concrete strength is affected by the location of the concrete in a structural element, with the concrete at the bottom tending to be stronger than the concrete at the top. Core strength is also affected by core orientation relative to the horizontal plane of the concrete as placed, with strength tending to be lower when measured parallel to the horizontal plane. 3 These factors shall be considered in planning the locations for obtaining concrete samples and in comparing strength test results. 3.4 The strength of concrete measured by tests of cores is affected by the amount and distribution of moisture in the specimen at the time of test. There is no standard procedure to condition a specimen that will ensure that, at the time of test, it will be in the identical moisture condition as concrete in the structure. The moisture conditioning procedures in this test method are intended to provide reproducible moisture conditions that minimize within-laboratory and between-laboratory variations and to reduce the effects of moisture introduced during specimen preparation. 3.5 The measured compressive strength of a core will generally be less than that of a corresponding properly molded and cured standard cylinder tested at the same age. For a given concrete, however, there is no unique relationship between the strengths of these two types of specimens (see Note 3 ). The relationship is affected by many factors such as the strength level of the concrete, the in-place temperature and moisture histories, the degree of consolidation, batch-to-batch variability, the strength-gain characteristics of the concrete, the condition of the coring apparatus, and the care used in removing cores. Note 3: A procedure is available for estimating the equivalent cylinder strength from a measured core strength. 4 Note 4: In the absence of core strength requirements of an applicable building code or of other contractual or legal documents that may govern the project, the specifier of tests should establish in the project specifications the acceptance criteria for core strengths. An example of acceptance criteria for core strength is provided in ACI 318, 5 which are used to evaluate cores taken to investigate low strength test results of standard-cured cylinder during construction. According to ACI 318, the concrete represented by the cores is considered structurally adequate if the average strength of three cores is at least 85 % of the specified strength and no single core strength is less than 75 % of the specified strength. 3.6 The “specifier of the tests” referenced in this test method is the individual responsible for analysis or review and acceptance of core test results. Note 5: For investigation of low strength test results, ACI 318-14 defines the specifier of the tests as the licensed design professional or building official. 3.7 The apparent compressive strength of concrete as measured by a core is affected by the length-diameter ratio (L/D) of the core as tested and this must be considered in preparing core specimens and evaluating test results.