Concreting technology and removing of the forms
Sagging of Fresh Concrete
Coefficient of elasticity is achieved as early as after 3 days at the level of 90 % of the value for 28th day – regardless of concrete compounding. Thus, for the fresh concrete only insignificant increase of elastic deformations comes in. Creep strains that become apparent after a number of years, exceed the elastic deformations several times. Early removal of the formwork – say, after 3 days instead of the 28 – results in the increase of total deformations less than by 5 %. In contrast to this, the dispersal of creep strain share as a result of various influences, i. e. humidity of the filling material or humidity of the air, varies in the range of 50 % to 100 % of standardized value. That is why the total sagging of the covering slab does not depend practically on the time of removing the forms.
| Solidification of Fresh Concrete |  |
| Finnish Birch Wood Sagging Graph |  |
| Pressure of Fresh Concrete upon Vertical Forms |  |
