Experiment and Research on Retard-Bonded Prestressed Steel Strands

Retard-bonded prestressed concrete which has appeared in recent twenty years is a new and distinctive prestressed system.The key of retard-bonded prestressed concrete is whether the retarding materials around prestressed tendons would satisfy its demand.So retard-bonded prestressed steel strands are made by manual work in this paper,and experiment and research on friction of retard-bonded prestressed steel strands are carried out.Initial setting time of retarding mortar is 11 days,and retard-bonded prestressed steel strands are tensioned on the 9th day in the paper.The static friction resistance,friction factor μ and deviation factor κ are obtained from the test when retard-bonded prestressed steel strands are tensioned.And the stress variation of retard-bonded prestressed steel strands both with the camber variation of retard-bonded partially prestressed concrete beams are acquired from the test during 40 days immediately after prestress transfer.It provides the theoretical reference for the actual project application of the new retard-bonded prestressed concrete system.