5.1 Drying behavior is related to the mass transport properties of concrete, such as liquid permeability and water diffusivity. It depends on a number of factors such as concrete mixture proportions, presence of admixtures and supplementary cementitious materials, composition and physical characteristics of the aggregates and cementitious materials, curing conditions, degree of hydration, and presence of microcracking. Drying behavior is also affected strongly by the degree of saturation and temperature of the concrete at the start of drying as well as the environmental conditions that exist during drying such as temperature, relative humidity, and air flow rate (wind speed).

5.2 This test method subjects initially saturated specimens of concrete to one-dimensional drying under controlled environmental conditions. The resulting mass loss versus time data can be used to estimate transport coefficients including liquid permeability3 and water diffusivity.4 These coefficients may be used in numerical models to estimate service life of concrete and reinforced concrete members exposed to different environmental conditions.5^,6

5.3 The test method provides instruction and a sequence of steps for measuring mass loss versus time. The preferred rate of this mass loss will depend on the application. For example, for interior commercial flooring applications, a mass loss that occurs quickly may be preferable, while for outdoor exposures in an aggressive environment, slower mass loss may be beneficial.