Development of High Strength Steel Strand for Prestressed Concrete
Toshio MAEHATA, Motohiro NAKANO and Hiroichi IOKA
Abstract:High-strength steel strands have been developed using higher strength steel wire rods with higher carbon and silicon contents than conventional steel wire rods. The tensile load of the developed steel strands was 15%`20% higher than the conventional steel strands: 322 kN for 15.2 mm diameter strands and 684 kN for 21.8 mm diameter ones. The developed strands have a fracture elongation comparable to the conventional ones. An increase in carbon concentration and dislocation density resulted in smaller relaxation loss than the conventional strands. The strengthening did not have negative effects on anchoring efficiency of the strands and hydrogen embrittlement. Therefore, special operations are not required for practical use of the developed high strength steel strands. Their higher-strength is expected to reduce the materials used for prestressed concrete members, to decrease the weight of concrete members, and shorten the construction period. Key Words:Prestressed concrete, High strength steel strand, High strength concrete, High carbon steel wire rod