UTJECAJ OPLATA KONTROLIRANE PROPUSNOSTI NA MEHANIČKA I TRAJNOSNA SVOJSTVA ZAŠTITNOG SLOJA BETONA

Abstract

Controlled permeability formworks (CPF) are made from fibrous membranes which absorbthe excess water and air from the surface layer of fresh concrete. By this mechanism, the surface layer of concrete with lower water-to-cement ratio, compared to the inner concrete, is created. The aim of the experimental research was to evaluate and compare the influence of two commercially available CPF materials on mechanical and durability properties of concrete. During preparation of concrete elements thickness of concrete cover was varied (3 and 5 cm). Also, once the set of samples was prepared, the same formwork was used again, to evaluate the possibility of multiple usage of the same material. Following mechanical and durability tests were performed: ultrasonic test, reboundnumber test, pull-off, gas permeability and capillary absorption test. Properties of concrete prepared with CPF were compared to the properties of concrete prepared in traditional wooden formworks.