What are the classifications of steel strand?

1. Categorized by application, our products include prestressed steel strand, electrical use, galvanized steel strand, and stainless steel strand. Prestressed steel strand is coated with anti-corrosion grease or paraffin and then wrapped in HDPE, referred to as unbonded prestressed steel strand. Some prestressed steel strand is also made from galvanized or galvanized aluminum alloy wire.

2. Categorized by material characteristics: steel strand, aluminum-coated steel strand, and stainless steel strand.

3. By structural classification: Prestressed steel strand can be divided into 7-strand, 2-strand, 3-strand, and 19-strand types. The commonly used structure is 7-strand. Galvanized steel strand for electrical use and aluminum-clad steel strand are also categorized by the number of steel wires, including 2, 3, 7, 19, and 37 structures, with the 7-strand structure being the most common.

4. By surface coating classification: It can be divided into smooth, steel strand, galvanized steel strand, coated epoxy steel strand, aluminum clad steel strand, copper plated steel strand, and sheathed steel strand, etc. Galvanized steel strand is commonly used for tension wires, guy wires, reinforcing cores, etc. It can also serve as earth wires for overhead transmission lines, barrier wires along highways, or structural wires in building structures.

Common steel strand can be divided into epoxy-coated unbonded prestressed steel strand and slow-bonded prestressed steel strand. Below, we briefly introduce these two types of steel strand.

Epoxy Coated Unbonded Prestressed Steel Wire: This involves applying a layer of grease and wrapping with a PE sheath on the smooth epoxy coated steel wire. During construction, the wire wrapped with the PE sheath is placed within the concrete. Due to the grease and sheath on the outside, the steel wire is isolated from the concrete, allowing for free movement which facilitates construction. It serves the same purpose as unbonded steel wire.

2. The slow-adhesive prestressed steel strand is composed of prestressed steel strand, an outer sheath, and a slow-setting gel adhesive filled between the steel strand and the sheath. The slow-setting gel adhesive is akin to a non-adhesive anti-corrosion grease in the early stage, offering some fluidity and good adhesion to steel. Under the chemical action of a hardener, the adhesive gradually solidifies, significantly enhancing its cohesion and toughness, while also generating bonding force with the prestressed steel strand and the outer sheath. The high-strength outer sheath, with its corrugated surface resembling a bellows, provides better bonding with concrete. Once the cementitious material is fully cured, the slow-adhesive prestressed steel strand achieves a reliable bond with concrete. The slow-adhesive prestressed concrete possesses mechanical properties similar to those of bonded prestressed concrete. Additionally, the cured slow-adhesive prestressed steel strand exhibits the same anti-corrosion properties as those of epoxy-coated steel strand. Therefore, projects like offshore, harbor, and prestressed concrete bridge construction, which are complex and must withstand corrosive medium侵蚀 after completion, benefit from the use of slow-adhesive prestressed steel strand.