Water and Water Vapor Penetration Through Coatings

Abstract

Water and water vapor transport in two-layer systems where one layer acts as water retarder are analyzed. In the experimental work, four external paints supposed to protect the underlying structure against water under common service conditions are applied on glass fiber reinforced concrete substrates. The water absorption coefficient and the effective water vapor diffusion coefficient are chosen as evaluation parameters for the assessment of water and water vapor transport properties of the systems. In the water absorption experiments, two consecutive quasi-steady regimes are identified, the first with an almost constant water flux into the system, and the second obeying the square-root-of-time rule for cumulative mass of water in the system. The water protective qualities of all studied paints can be considered as satisfactory for common service conditions. The effective diffusion coefficients of all systems are found to be within the error range of the measuring method compared to the substrate itself, which is a very positive feature for external paints.

The Effect of Aggregate Type on the Properties of Lime Mortars

“…The water absorption coefficient of each specimen was calculated from the linear part of the dependence of the increase of tested sample's mass on the square root of time. Then, the apparent moisture diffusivity was calculated using the saturated moisture content and water absorption coefficient [13].…”

Influence of the Aggregate Type on the Properties of Dolomitic Lime-Based Mortars

“…The water absorption coefficient of each specimen was calculated from the linear part of the dependence of the increase of tested sample's mass on the square root of time. Then, the apparent moisture diffusivity was calculated using the saturated moisture content and water absorption coefficient [19].…”