: Jentsch, T.; Baumbach, H.; Zeuner, A.

Abstract
Using radioactively labelled water, one-dimensional moisture profiles were measured at concrete cubes (a=150 mm) in dependence on time. Five surfaces of each specimen were sealed by a special epoxy resin. The moistening was fed through the whole upper unsealed surface. Like in nuclearmedical practice. 99mTc as pertechnetate-ion was used to label the water. The measurements were relised at concrete-cubes with a water/cement-ration of 0.4 and 0.6. The labelled water penetrates deeper into the specimen with the larger w/c- ratio than into the specimen with smaller w/c-ration during comparable periods. It is possible to describe the procedure of moistening of concrete by the second Fick's law. That is shown from drawings of measured values of diffusivity calcurlated from the measured counting rates are in the range of 10-9 to 10-7m2/s.