29/03/2013
Reinforcement covering
The reinforcement covering is required for the following reasons:
a. Protection of reinforcement from corrosion (rusting).
b. The need for adequate adhesion between the steel and concrete.
c. Fire protection: the concrete that covers reinforcement protects it from deformations caused by the development of high temperatures due to fire in the building.
d. The need to create cable and pipe channels without harming the reinforcement [*]NoteThe channel is the carving that an electrician or a plumber does in order to engrave a recess channel in a structural element. Inside these channels he places electric cables or pipes. Usually any electrical or mechanical equipment should be planned ahead to be implemented inside adequate pipes , or by designing recesses inside the concrete coating thickness. Only when there a change in the initial planning should the carving process be done. Even then, extra caution should be taken not to ‘cut’ any transverse or longitudinal reinforcement and to ensure that these channels are smaller than the concrete coating thickness.
Generally coverings secured by the use of plastic spacers have a considerable material pro-curement cost as opposed to their low implementation cost.
Of course it is possible to use other “common” materials as well, like pieces of marble. These although they have a low procurement cost their implementation is economically demanding. However, their largest problem is their correct application since they are placed after the posi-tioning of reinforcement and prior to the concrete casting.
In cases where visible concrete surfaces (off-form concrete or architectural concrete) is re-quired, one may use point or linear spacers made out of fiber reinforced concrete or even rebar chairs with fiber reinforced concrete tipped legs.
