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American Standard Advanced Bond Infrastructure Grade. Engineered in strict compliance with ASTM A416 Grade 270 specifications, our 12.7mm (0.5 inch) retarded post-tensioning prestressed concrete steel strand combines the friction-free installation flexibility of unbonded tendons with the ultimate structural composite strength of bonded systems, delivering certified compliance for advanced civil engineering.
ASTM A416 12.7mm (0.5 inch) Retarded Post-Tensioning Strand | Delayed-Bond 7-Wire Tendon
​Designed for critical post-tensioned floor systems and transfer structures requiring delayed bonding under ASTM design codes. Every coil adheres to rigorous mechanical and chemical benchmarks.
|
Technical Parameter |
Specification Value |
Governing Standard |
|
Nominal Diameter |
12.7 mm (0.500 inch / 1/2") |
ASTM A416 / A416M |
|
Strand Configuration |
7-Wire (1 Center Wire + 6 Helical Outer Wires) |
ASTM A416 |
|
Nominal Cross-Sectional Area |
98.7 mm² (0.153 in²) |
ASTM A416 |
|
Specified Tensile Strength |
Grade 270 (1860 MPa High Tensile) |
ASTM A416 |
|
Minimum Breaking Load (MBL) |
≥ 183.8 kN (41,300 lbs) |
ASTM A416 |
|
Bonding Technology |
Retarded Bonding Compound (Delayed Hardening) |
Specialized PT Technical Specs |
|
Relaxation Class |
Class 2 (Low Relaxation, Max 2.5% at 1000h) |
ASTM A416 / JIS G3536 |
· ​ASTM A416 Certified Mechanical Core: The underlying 7-wire strand is manufactured strictly to meet the strength, elongation, and ultimate breaking load requirements of ASTM A416 Grade 270.
· ​Construction Flexibility + Composite Strength: Functions as an unbonded tendon during placement and stressing (allowing easy friction-free tensioning), then chemically cures and bonds with surrounding concrete over time to achieve full composite action.
· ​Superior Crack Control & Shear Capacity: Once fully bonded, it distributes structural stresses evenly along the entire tendon length, significantly improving crack resistance and ultimate load-bearing performance compared to standard unbonded systems.
· ​Full Metallurgical Traceability: Manufactured under strict ISO 9001 protocols. Each commercial shipment includes a comprehensive Mill Test Certificate (MTC) verifying tensile strength, minimum breaking load, and compound activation timelines.
​Engineered for high-performance structural systems utilizing ASTM design frameworks:
· ​Commercial & Residential Buildings: Flat-plate floor slabs, multi-story parking structures, heavy transfer girders, and high-rise commercial towers.
· ​Bridge & Transportation Infrastructure: Precast bridge beams, continuous box girders, and highway viaduct structures.
· ​Specialized Industrial Structures: Large-span industrial roofs, heavy storage foundations, and containment structures.
​Q: Do these retarded strands comply with ASTM A416 mechanical specifications?
A: Yes. The base 7-wire strand complies strictly with ASTM A416 Grade 270, ensuring complete mechanical reliability while utilizing advanced retarded bonding compound technology.
​Q: How does the retarded bonding compound work during installation?
A: During placement and stressing, the compound acts like an unbonded coating, allowing smooth tensioning. Over a controlled curing period, the material hardens to permanently bond the strand to the surrounding concrete.
​Q: What is the standard export packaging and protection?
A: Coils are carefully wrapped with heavy-duty protective materials and moisture barriers, secured with high-tensile steel strapping, and palletized to ensure the integrity of the specialized coating during transit.
