Permeation and diffusion tests for estimation of durability of fibreconcretes with dense aggregate and recycled concrete

Abstract

Mechanical and deformational properties of concrete are markedly improved by the addition of long structural fibres. This addition, however, not always improves the durability of concrete. One important factor for an estimation of concrete durability is to assess the permeation and diffusion characteristics of the surface layer. The research was performed by means of the TORRENT permeability method and the method for determination of the nonsteady-state migration coefficient of chlorides in concrete – NORDTEST. The addition of long polypropylene fibres contributes to increasing the permeability of the surface layer for air and chloride solution, but no too significantly. The higher permeability was determined in concrete with concrete recyclate and polypropylene fibres. The measured results by both used methods are partially comparable and can be used for raw estimation of durability of concretes. The higher values of permeability indicate the expected lower durability of tested concretes.Mechanical and deformational properties of concrete are markedly improved by the addition of long structural fibres. This addition, however, not always improves the durability of concrete. One important factor for an estimation of concrete durability is to assess the permeation and diffusion characteristics of the surface layer. The research was performed by means of the TORRENT permeability method and the method for determination of the nonsteady-state migration coefficient of chlorides in concrete – NORDTEST. The addition of long polypropylene fibres contributes to increasing the permeability of the surface layer for air and chloride solution, but no too significantly. The higher permeability was determined in concrete with concrete recyclate and polypropylene fibres. The measured results by both used methods are partially comparable and can be used for raw estimation of durability of concretes. The higher values of permeability indicate the expected lower durability of tested concretes.