This specification deals with the standard types and grade requirements of seven-wire, uncoated steel strands for use in the construction of pre-tensioned and post-tensioned pre-stressed concrete. The two types of strand are low-relaxation and stress-relieved (normal relaxation). The base metal shall be made of carbon steel and shall undergo stranding and continuous thermal and mechanical treatment. Mechanical testing methods shall be performed to determine the breaking strength, yield strength, elongation, and stress relaxation properties wherein the strand shall conform to the required mechanical attributes of the product. Final products shall be furnished on reels or in reelless packs for packaging and marked with two strong tags for identification. The requirements specified herein shall also be applicable for pre-stressed ground anchor construction.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This specification covers two types and two grades of seven-wire, uncoated steel strand for use in pretensioned and post-tensioned prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand shall be regarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless specifically ordered, or by arrangement between purchaser and supplier. Grade 1725 [250] and Grade 1860 [270] have minimum ultimate strengths of 1725 MPa [250 ksi] and 1860 MPa [270 ksi], respectively, based on the nominal area of the strand.

1.2 The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

1.3 The supplementary requirements in S1 shall be specified for 15.2-mm [0.600-in.] diameter uncoated seven-wire steel strand if needed for applications in prestressed ground anchors.

2. Referenced Documents

ASTM Standards
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A981 Test Method for Evaluating Bond Strength for 15.2 mm (0.6 in.) Diameter Prestressing Steel Strand, Grade 270, Uncoated, Used in Prestressed Ground Anchors
E328 Test Methods for Stress Relaxation for Materials and Structures
U.S. Military Standards
MIL-STD-163 Steel Mill Products Preparation for Shipment and Storage
U.S. Federal Standard
Fed.Std.No.123 Marking for Shipments (Civil Agencies)

Index Terms

prestressed concrete; seven-wire strand (tendon); steel wire; Concrete reinforcement--specifications; Prestressed concrete; Seven-wire strand (tendon); Steel wire (prestressed concrete); Steel wire strand--specifications ; ICS Number Code 77.140.15 (Steels for reinforcement of concrete)

Citing ASTM Standards

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