【国外标准】 Standard Specification for Returned Fresh Concrete for Use in a New Batch of Ready-Mixed Concrete

This specification covers requirements for returned fresh concrete for use in a new batch of ready-mixed concrete, as well as the requirements specified by the purchaser. If the requirements of the purchaser differ from those prescribed in this specification, the purchaser's requirements shall take precedence. This specification does not cover the placement, consolidation, curing, or protection of the concrete after delivery to the purchaser, and by itself shall not grant permission to the manufacturer to use returned fresh concrete in a new batch of concrete.This specification covers: ordering information; measuring materials; requirements for use; and information to be reported by the manufacturer to the purchaser, such as the amount of returned fresh concrete in cubic meters [cubic yards] and information for certification purposes as designated by the purchaser and required by the job specifications.1.1 This specification covers returned fresh concrete for use in a new batch of ready-mixed concrete. Requirements for returned fresh concrete shall be either as hereinafter specified or as specified by the purchaser. In any case where the requirements of the purchaser differ from those in this specification, the purchaser’s requirements shall govern. This specification does not cover the placement, consolidation, curing, or protection of the concrete after delivery to the purchaser.1.2 This specification by itself shall not grant permission to the manufacturer to use returned fresh concrete in a new batch of concrete.NOTE 1: The permission to use returned fresh concrete may be addressed in purchase documents, which may reference this specification.1.3 Returned fresh concrete in a quantity of less than 450 kg [1000 lb] or 0.2 m3 [0.25 yd3] shall not be subject to this specification.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 nonconformance with the standard.1.5 The text of this standard references notes and footnotes, which provide explanatory information. These notes and footnotes shall not be considered as requirements of the standard.1.6 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 use.2)1.7 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.