The durability of a concrete structure is conditioned upon the quality of the used concrete and the influence of aggressive media. A solid and uniform concrete components surface protects its interior against intrusion of aggressive factors, and the reinforcement placed inside - against corrosion. A sealed concrete surface delays penetration by minerals, oxygen, humidity and carbon dioxide, which contributes to a marked extension of the usable life time of a concrete structure.
Thanks to the use of Formtex mats, one can achieve a decidedly better concrete outer surface than just using the traditional method, when the poured concrete adheres directly to the formwork panel. In the traditional method, the formwork panels are covered with an anti-adhesion fluid before concreting, which is not necessary if Formtex mats are used. The achieved concrete surface, if Formtex mats are used, is particularly tight, has no pores or microfractures, which means that it protects the interior of the concrete and any possible reinforcement perfectly from the actions of an aggressive environment.
|Formtex formwork mat
| FORMTEX 2,75
| FORMTEX 3,20
The Formtex formwork mat is composed of capillary polypropylene pipes embedded in a semi-permeable membrane. As a result of use of a special technology, a membrane with a thickness of 0,1 mm was achieved, with pores the diameter of a water molecule, which lets pure water molecules and gaseous substances pass through. The second mat layer, with a thickness of 1,1 mm, provides a drainage function.
Mat attachment type depending on formwork type.
The Formtex mat is attached to wooden formwork using staples, after prior tensioning thereof. For steel formwork, the mat needs to be glued to the formwork using a special Formtex adhesive. When gluing, a remaining fabric leftover must be left spanning 5 cm from each side. The Formtex mat was tested and is suitable for use twice. However, before it is used again, it must be checked whether it is damaged, and any contaminations must be cleaned.
Advantages stemming from the use of Formtex mats
The reduction of permeation of chlorides, water, the increase of resistance to damage due to frost and concrete carbonisation, the usable lifetime of the concrete structure extends. The use of the Formtex mat reduces the number of bubbles on the concrete surface. They are perfect in pre-casting plants, providing advantageous treatment conditions and reducing the water/cement ratio for freshly poured concrete.
The rate of water removal depends on the concreting height and the concrete make-up (a typical value range is 0,5 l/m2 to 3,0 l/m2). Microfractures caused by concrete contraction are not present, because the mat contains large volumes of humidity, which cares for the concrete in the first binding phase. Apart from that, there are no blooms or concrete surface contaminations caused by the use of anti-adhesion compounds.