Verfolgung der Trocknung von Estrich mit Hilfe von ultrabreitbandigen Mikrowellen und luftgekoppelten Antennen (Deutsch)

The drying behavior of a freshly prepared anhydrite screed and a cement screed sample was investigated using ultrawideband microwave signals in the frequency range between about 1 GHz and 10 GHz in the reflection mode in nondestructive and contact-free way. For this purpose, the method of frequency-stepped continuous wave radar was used. At first, the back wall signal of the specimen was not recognizable due to the high attenuation of microwaves by water in the still moist sample. After a few weeks of drying, a signal was detected and increased with continued dessication, until a constant level was reached. At the same time, the position of the back wall signal shifted to smaller times due to the increase of the propagation velocity of the microwaves until here again a constant value was reached.