Unbonded steel strand: 

Slow bond unbonded steel strand is a new unbonded steel strand between unbonded steel strand and bonded steel strand in a good bond situation, that is, it has no effect on the bonding freedom of the bonded steel strand, can be convenient to use, and does not need to pass the hole setting and grouting benefits. It also has a new prestressing technology which has the characteristics and safety of bonded steel strand in later use.

The action mechanism of unbonded steel strand is to wrap a special layer of retarded mortar around the unbonded steel strand. The sealing temperature of the mortar is required to be 5 ~ 40 ° C, and it cannot condense 30 days before, which meets the time requirements of on-site tensile reinforcement. After 30 days, we begin to develop gradual hardening, and produce a gripping effect on the unbonded steel strand, and can get a compressive strength that can eventually reach more than 30MPa. One of the mechanisms is that doped retarder is adsorbed on the surface of cement particles or hydration products, which weakens the interaction between water molecules and Ca, SO+ plasma and C3A substance, and it is difficult for anchoring agent to quickly form ettringite crystals, which plays a retarding role.

HONGXING GROUP