The prestressing steel strand used in prestressing is typically made of high-strength, low-relaxation steel. It is commonly known as prestressing strand or prestressing wire. The prestressing steel strand is composed of multiple individual steel wires twisted together to form a helical shape. The wires are usually made of high-carbon steel with a diameter ranging from 5 to 15 millimeters.

The steel used for prestressing strand has high tensile strength, typically in the range of 1,860 to 2,200 megapascals (MPa). This high strength allows the strand to withstand the forces applied during prestressing without breaking.

To enhance the durability and performance of the strand, it is often coated with a protective layer of zinc or epoxy. This coating helps prevent corrosion and improves the bond between the strand and the surrounding concrete.

Prestressing strand for prestressed concrete is commonly used in various construction applications, such as precast concrete elements, bridges, high-rise buildings, and other structures that require enhanced load-bearing capacity and reduced deflection.

Prestressing Steel Strand Types

There are several types of prestressing steel strands used in construction, each designed to meet specific project requirements. Here are some common types:

1. Uncoated Prestressing Strand: This type of strand consists of multiple steel wires twisted together without any protective coating. Uncoated strands are primarily used in applications where corrosion protection is not a concern, such as temporary structures or indoor applications.

2. Galvanized Prestressing Strand: Galvanized steel strands have a zinc coating applied to the surface of the steel wires. The zinc coating provides corrosion resistance, protecting the strand from environmental elements. Galvanized steel strands are commonly used in situations where the structure may be exposed to moisture or corrosive conditions.

3. Epoxy-Coated Prestressing Strand: Epoxy-coated steel strands are coated with a layer of epoxy resin to provide corrosion protection. The epoxy coating creates a barrier between the steel and the surrounding environment, preventing the ingress of moisture and corrosive agents. This type of strand is widely used in structures where long-term durability is essential.

4. Stainless Steel Prestressing Strand: Stainless steel strands offer excellent corrosion resistance due to their high chromium content. They are particularly suitable for applications where the structure will be exposed to aggressive environments, such as marine environments or chemical plants.

5. Low Relaxation Prestressing Strand: Low relaxation strands are manufactured using a specialized process that minimizes the amount of relaxation or elongation that occurs over time. This type of strand is used when precise control of prestress losses is crucial. Low relaxation strands help maintain the desired level of prestress in the structure over an extended period.