What is the difference between prestressed concrete and post tension concrete for bridge works?
MF: Precast members may be comprised of unstressed reinforced concrete or prestressed concrete. Steel tendons in prestressed concrete members is tensioned before the concrete is placed around it; this usually takes place in a casting yard at or near the concrete plant. In post-tensioned concrete, the members are formed and cast in the field, and require support by shoring or the earth. Ducts with the tendons to be stressed are cast into the reinforced concrete members. The tendons are stressed after the reinforced concrete has cured enough to take the compressive stress exerted by the tendons. After stressing, the tendon ducts may be filled with grout.
