Crack-bridging ability and liquid water permeability of protective coatings for concrete

A surface coating for concrete can be exposed to a wide range of environments, movements and stresses depending on which application the structure is used for. Therefore the coatings have different requirements to satisfactorily protect concrete constructions in different service environments. Water permeability is an important factor to be considered in evaluating the performance of a coating since water penetration generally leads to the degradation of the substrate (concrete) and/or to the electrochemical reaction of steel when it is present (reinforced concrete). The crack-bridging ability of coatings is another important characteristic that has to be evaluated to assess if a coating can protect a concrete structure which surely will crack. This study investigates the relative importance of the parameters water perme- ability rate and viscoelasticity of coatings for different applications