Products for prestressed concrete

Products for prestressed concrete

Steel wires and strands for prestressed concrete

Emcocables manufactures wires and strands for pre-stressed concrete as well as strands and wire ropes for self-supporting structures.

Steel wires

EMCOCABLES manufactures a wide variety of high carbon wires. Included are wires for reinforced concrete used as structural support in the pre-stressed, post tension and pre-cast industries.

EMCOCABLES produces in accordance to all internationality recognized specifications such as ASTM, UNE, NTC and others.

The wires are used specifically for pre-tensed structures. (See Table)

Strands

Generally, strands are comprised of one central wire and six external wires rolled helicoidally around the central wire. These strands are manufactured bright or galvanized conditions and/or extruded with high-density polythene, according PTI and other recognized standards.

Standards NTC 2010 and ASTM A 416.

Properties of Coating

The Zinc used for the coating of the wires that comprise galvanized strand is of the highest purity grade, SHG (Special High Grade), in accordance with ASTM B 6 standard. This guarantees the formation of a Zinc-Iron bond sufficiently strong in order to achieve the most efficient galvanic protection of the steel.

The mass of the Zinc coating in g/m2 should be homogenous over the entire length of the wires, meeting the requirements and / or standards previously agreed up with the client, for example: ASTM A 475, BS 183 (British Standard), ASTM A 363, EMCOCABLES standards and/ or client standards.

In addition to 7 wire strands, EMCOCABLES manufactures two wire strand and three wire strands, based on customer and/or international standards. EMCOCABLES also produces indented strands based on the ASTM A 886 standard.

Note 2: The indented two and three wire strands have an ultimate tensile strengthen of Min.1660 Mpa with a min. 3.5{79786cb4857aadb4402e6b20da24c0d819b2abf66a0a8433b3397f58e29ffc5a} elongation

Extruded strands

The break load properties, 1{79786cb4857aadb4402e6b20da24c0d819b2abf66a0a8433b3397f58e29ffc5a} elongation load, lay length, and diameter are the same required properties as the uncoated strand. These are properties that are established by the ASTM A 416 standard and shown in tables 2 and 3.

The specifications for the coating established by the Post-Tensioning Institute are related into the following paragraphs:

Coating (jacket) Properties

    • High resistance and durability to avoid damage to the strand during manufacturing, transport, installation and or tensioning
    • Hermetic seal over the entire length of the coating
    • Will not react to concrete, steel, nor the corrosion inhibitor (grease)
    • The minimum thickness of the coating (jacket) should not be less than 1.00mm (0.040”) for high density polyethylene and/or polypropylene, of high density or its equivalent if other materials are requested.
    • The internal diameter of the coating (jacket) should be at least 0.76mm (0.030”) greater than the maximum diameter of the strand.

Corrosion Inhibitor
The covering for the corrosion inhibiting materials must have the following properties:

    • Must be chemically stable and not react with steel, the jacket material, or concrete.
    • Must have the necessary polarity to reject humidity.
    • Provide adequate lubrication between the strand and jacket