【国外标准】 Standard Test Method for Density and Air Content (Pressure Method) of Freshly Mixed Roller-Compacted Concrete

4.1 The test determines the air content of freshly mixed RCC exclusive of any air that may exist inside voids within aggregate particles. For this reason, it is applicable to concrete made with normal-density or high-density aggregate particles and requires determination of the aggregate correction factor described in Test Method C231/C231M.4.2 If the concrete being tested contains aggregate that would be retained on a 50 mm (2 in.) sieve, the air content of the total mixture is only approximated by the test.4.3 The test determines the density of freshly mixed RCC containing aggregate with a maximum size not greater than 50 mm (2 in.).4.4 The density and air content of hardened RCC may be either higher or lower than that determined by this test method. This depends upon the methods and amount of consolidation effort applied to the RCC from which the hardened concrete specimen is taken; uniformity and stability of the air bubbles in the fresh RCC; accuracy of the microscopic examination, if used; stage in the delivery at which the density and air content of the unhardened RCC are determined; and other factors.1.1 This test method covers the determination of density and air content of freshly mixed roller-compacted concrete (RCC) using the apparatus described in Test Method C231/C231M and the vibrating hammer described in Test Method C1435/C1435M.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 are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.NOTE 1: Sieve size is identified by its standard designation in Specification E11. The alternative designation given in parentheses is for information only and does not represent a different standard sieve size.1.3 The text of this test method references notes and footnotes that provide explanatory information. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this 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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.)21.5 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.