【国外标准】 Standard Practice for Molding Roller-Compacted Concrete in Cylinder Molds Using a Vibrating Hammer

4.1 This practice, intended for use in testing roller-compacted concrete, may be applicable to testing other types of cementitious material such as coarse-grained, soil-cement. This practice provides standardized requirements for molding stiff to very dry consistency concrete mixtures commonly used in roller compacted concrete construction. This practice is used instead of rodding or internal vibration, which cannot properly consolidate concrete of this consistency.NOTE 1: Further description of roller compacted concrete consistency is given in ACI 207.5R and ACI 211.3. The consistency of concrete using a vibrating table may be determined in accordance with Test Methods C1170/C1170M.4.2 This practice is used to mold cylindrical test specimens commonly used for testing compressive or tensile strength of concrete. Specimens tested for compressive strength and splitting tensile strength shall be in accordance with Test Methods C39/C39M and C496/C496M, respectively. Test specimens also may be used to determine density of fresh concrete.NOTE 2: For some extremely dry mixtures; (those with a consistency greater than 45 s when tested in accordance with Test Methods C1170/C1170M)5 the density of specimens made in accordance with this practice may be greater than the in-place density of roller-compacted concrete due to the greater potential for voids at the bottom of the lifts in the field.NOTE 3: The mass of the apparatus and amount of force applied by the operator may significantly affect the density of specimens made from these mixtures; thus, discretion is advised when interpreting test results on specimens made according to this practice.1.1 This practice2 covers molding cylindrical test specimens from concrete when the standard procedures of rodding and internal vibration, as described in Practice C31/C31M and Practice C1176/C1176M, are not practicable. This practice is applicable to freshly-mixed concrete, prepared in the laboratory and the field.1.2 Freshly-mixed concrete is molded in cylindrical molds using an electric vibrating hammer equipped with a shaft and circular plate.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. 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.1.4 The text of this practice 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 this practice.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.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.