Advantages of Unbonded post tensioning over Bonded post tensioning

General Advantages:

• Usually the consumption of conventional steel remains more or less same because of the practical consideration of delays in grouting (more often in case of bonded system) after the stressing activity

• Post tensioncable consumption would be lesser for same level of stresses and deflections for serviceability aspects

• Faster installation

• Long-term Durability (Corrosion Protection by sheathing and anti-corrosive grease coating on cable)

• Encapsulated Unbonded System for effective protection against corrosion

• Slabs reinforced with Unbonded post tension system have better control over the tensile stresses and deflection

• Grout testing is expensive and time consuming

• Water cement ratio for grouting to maintain on site is difficult

• Post construction changes, making cutouts and re-adjustments in cable profiles is not possible once the grouting is done

• Cable experiences more frictional effects in case of Bonded system due to corrugated duct and inter-cable movements. There is a grease inside the sheathing which reduces the friction effects in case of Unbonded system

• Post-earthquake residual deformation is minimized

• Once grouted it is hard to fix any problem in Bonded System