【国外标准】 Standard Test Method for Evaluating Bond of Seven-Wire Steel Prestressing Strand

5.1 Prestressing steel strand is used in pre-tensioned and post-tensioned concrete construction.5.2 In pre-tensioned concrete applications, the prestressing steel strand is expected to transfer prestressing forces to the structural member by means of the adhesion (that is, bond) of the exposed wire strand surfaces to the surrounding cementitous material.5.3 Manufacturing processes, subsequent handling, and storage conditions can influence the strand bond.5.4 Prestressing steel strand is used in construction applications with a variety of concrete mixtures. Developing tests and threshold values for the performance of the strand in each of these unique mixtures is impractical.1.1 This test method describes procedures for determining the bond of seven-wire steel prestressing strand. The bond determined by this test method is stated as the tensile force required to pull the strand through the cured mortar in a cylindrical steel casing. The result of the test is the tensile force measured on the loaded-end of the strand corresponding to a movement of 0.1 in. [2.5 mm] at the free-end of the strand.1.2 This test method is applicable either in inch-pound units (as Test Method A1081) or SI units (as Test Method A1081M).1.3 The values stated in either inch-pound units or in SI units are to be regarded separately as standard. Within the text, SI 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 test method.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.