Moisture measurements in building materials with microwaves

The method requires two parallel boreholes in the specimen in which two mic rowave antennae can be moved. The moisture content in the material can be c alculated from the microwave intensity transmitted between the two borehole s. Moisture profiles along the boreholes can be obtained by moving the ante nnae in steps along the length of the boreholes and taking measurements at each step. The microwave frequencies used in the laboratory measurements ranged from 8 to 16.5 GHz in steps of 0.5 GHz. The diameters of the antennae were betwee n 7 and 9 mm, and of the boreholes between 8 and 12 mm. The microwave metho d produced measurement uncertainties between 0 and 2% by volume for all the materials studied in this report. (C) 2001 Published by Elsevier Science L td.