FIBRETEX geosynthetics solutions encompass Controlled Permeability Formwork (CPF) liners, designed for concrete surface enhancement in harbour infrastructure projects.
“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,” says technical sales engineer, Fibertex South Africa, Brian Potgieter. “Typical applications for this material in harbour infrastructure, include wharfs, bridges, tunnels, precast concrete units and marine structures. Apart from harbour projects, these liners are also used in water treatment plants, drinking water tanks, as well as dams and sluices.
“Degradation of concrete structures is normally accelerated by the effects of salt water, high temperature and increased CO2 levels in the air. Traditional formwork is impermeable to air and water, which leads to water and air migrating to the interface between the formwork and concrete. The result is an increased water/cement ratio in the cover region, where air bubbles also become entrapped and lead to the development of pinholes. The use of an innovative material like Formtex CPF liner could potentially double the lifetime of a concrete marine structure, by improving the quality of the covercrete,” says Potgieter.
Formtex is a two-layer CPF liner, consisting of a drainage layer that allows 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/cement (w/c) ratio in the concrete cover is reduced. This results in a denser and stronger concrete, with a blemish-free surface.
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.
Formtex also reduces the formation of blowholes and other blemishes on the concrete surface that normally require extensive deburring after the formwork is removed.
