Which of the following is a disadvantage of Freyssinet system?

After the tensioning operation, the space between the tendons and the ducts are _______

The commonly used mechanical devices used in the following statement.

The method of tensioning Magnel-Balton system involves _______

The period of cooling in thermo electric pre stressing is observed as _______

The tendons in the pretensioning system are tensioned between _______

The Hoyer’s method of prestressing is done by _______

The yield stress relieved in wires is about _______