Title: Draining Concrete - Controlled Permeability Formwork

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Publication: CIA

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Date: 2/13/2011

Abstract:
Deterioration of reinforced concrete structures is a major problem worldwide. The durability of concrete structures, to a large extent, depends on the quality of the concrete cover; its ability to resist aggressive elements penetrating the concrete cover, attacking the reinforcement and damaging the concrete structure. Controlled Permeability Formwork (CPF) liner is tensioned and fixed to the formwork. The nonwoven CPF liner drains surplus water and air from the surface of freshly placed concrete. When water is drained off the surface, the water/cement ratio (w/ c) in the concrete surface is reduced which improves the strength and durability of the concrete dramatically. In short: you treat the problem, and not the symptoms. This paper will focus on the improvement of the concrete, based on independent laboratory results. A comparison of nonwoven CPF liner as opposed to ordinary formwork will be presented. Furthermore the change of w/c-ratio throughout the depth of the concrete will be presented.