Gamma-ray-attenuation used for measuring the moisture content and homogeneity of porous concrete

The method of gamma-ray-attenuation for the determination of moisture content has the advantage of being non-destructive and independent of temperature gradients in the material. It is also possible to check the homogeneity of specimens by this method. The Laboratory of Thermal Insulation has equipment with a 100 mCi Am241 source for measurements on porous concrete. The paper gives a survey of the theory for gamma-ray-attenuation and the calibration of the equipment including measured values found for this equipment. At the end some examples are given of measurements of homogeneity and moisture content for different specimens.