Conference Dates

June 22-27, 2014


The aim of present study is to develop a practicable accelerated experimental method to obtain desorption isotherm of concrete more quickly and more reliably. A large number of sliced samples with thickness of 1, 2 and 3 mm have been de-saturated from fully water-saturated state to dry state. Time needed to obtain a mass stabilization varies from 14 to 30 days for concrete CEM I at a given relative humidity. Time saving is remarkable especially at lower relative humidity. Thinner samples lose their masses more quickly in the first week, but the thickness has hardly any influence on the total relative mass loss once the mass stabilization is reached. The analysis of images obtained by X-ray microtomography shows that water content and relative mass loss between two successive relative humidity steps have a nearly linear relationship with aggregate volume fraction except for very high relative humidity, which may be attributed to the difference between volume fraction of interfacial transition zone in different slices.