BUILD A BRIDGE The Formtex CPF liners reduce the formation of blowholes and other blemishes on concrete surfaces
Geosynthetics solutions company Fibertex encompasses controlled permeability formwork (CPF) liners – Formtex CPF liners – designed for concrete surface enhancement in harbour infrastructure projects.
Formtex is a two-layer CPF liner, consisting of a drainage layer that enables water and air to escape and a filter layer with a pore size designed to retain cement particles. When surplus water and air is drained from the surface of the freshly poured concrete during compaction, the water to cement ratio in the concrete cover is reduced. This results in a denser and stronger concrete, with a blemish-free surface.
“The main functions of Formtex CPF liners at harbours and ports are to improve the durability of a concrete structure, to extend its service life and reduce maintenance costs. Typical applications for this material include bridges, tunnels and marine structures,” says Fibertex SA CEO Clive Hitchcock.
Formtex CPF liners, which are suitable for the rounded shape of concrete elements, are suitable for use in the casting of bridge pillars and bridge spans, to ensure high quality, durability and low maintenance of the concrete elements that need to withstand highly aggressive environments.
He notes that degradation of concrete structures is normally accelerated by the effects of salt water, high temperature and increased carbon dioxide levels in the air. However, Formtex’s design features ensure that project requirements, demanding a service life of concrete of more than 120 years, are adhered to.
The Formtex CPF liners also reduce the formation of blowholes and other blemishes on the concrete surface that normally require extensive deburring after the formwork is removed. The smooth, dense and strong concrete cover is dust-free and because there are no release agents, it is an ideal prepared base for further surface treatment or coatings.
The liners, which reduce micro bacterial growth, are a highly efficient alternative to slip agents for freshwater supply structures. CPF liners also minimise the penetration of graffiti media, making it easy to remove from a surface.
Formtex is designed for tensioned, glued or self-adhesive mounting to vertical or inclined surfaces. Once Formtex is attached, concrete casting is performed as usual. These liners can easily be removed from the concrete during formwork striking.
The Fibertex geosynthetics range encompasses nonwoven and woven geotextiles, gabions and mattresses, drainage pipes and fittings and erosion control and cellular confinement solutions. The company also supplies soil reinforcing products, including geogrids and geocells, as well as geosynthetic clay liners as part of composite lining systems in modern landfills.
The products are manufactured to consistent quality standards at all production facilities globally and are supported by a technical advisory and backup service.
Hitchcock mentions that, apart from harbour projects, the liners are also used in water treatment plants, drinking water tanks, as well as dams and sluices.