Do you know what are the types of PC strands? As a PC strand manufacturer, we share this article with you.
Bonded prestressing strand is a stranded steel cable composed of multiple high-strength steel wires that have been stress relieved (stabilized). It is suitable for prestressed concrete or similar applications. The main characteristics of bonded prestressing strands are high strength and good relaxation, in addition to being straighter when unfolded. The common tensile strength grade is 1860 MPa, and there are also strength grades such as 1720, 1770, 1960, 2000, 2100 MPa. The yield strength of this steel is also higher.
Unbonded prestressing strand is made of ordinary prestressing strand coated with anticorrosive grease or paraffin wax and then wrapped with high-strength polyethylene. Bondless prestressing strands are mainly used in post-tensioning prestressing systems, the difference between them and bonded prestressing strands is that the prestressing does not bond with the surrounding concrete. During its working period, the prestressing tendon is always allowed to slide longitudinally relative to the surrounding concrete. The prestressing force is transmitted to the concrete exclusively by the anchorage. During construction, the unbonded tendons can be laid directly into the formwork like ordinary reinforcement. The concrete is then poured and the anchorage is tensioned after the concrete has reached its design strength, without the need for pre-drilled holes, grouting, etc.
Epoxy-coated filled strand has an average epoxy coating thickness of 0.6~0.8mm and is tested for continuity of coating before production. It is ensured that there are no more than 2 pinholes per 30m when the product leaves the factory. In addition to the excellent anti-corrosion properties, the epoxy resin coating has sufficient toughness. In the process of steel strand stretching, the epoxy resin coating extends synchronously with the steel wire without brittle cracking. When the strand is broken at the limit, the epoxy resin coating is consistent with the strand fracture. Compared with the PC strand, its ultimate strength is increased. The strand is completely wrapped with epoxy resin so that the strand forms a solid whole. Therefore, when the strand is tensioned with a clip anchor, the material properties of each wire are fully utilized. The overall strength of the strand can be increased by 2% to 3%.
It uses special surface treatment technology and a high-pressure electrostatic spraying method. It forms a uniform epoxy resin anti-corrosion layer with a certain thickness on the steel substrate. Make the physical and chemical properties of the product stable. It has the characteristics of heavy anti-corrosion, acid resistance, alkali resistance, salt resistance, temperature resistance, insulation, etc. The products are used in bridges, docks, airports, major buildings, sewage plants, especially on marine buildings. It can improve the service life by more than 50 years and is a new type of anti-corrosion steel for construction.
Huayongxin provides PC Strand Bonded and PC Strand Unbonded. If you are interested in our products, please feel free to contact us.
