X-ray attenuation technique for the analysis of moisture flow in porous building materials

Microfocus X-ray radiography is presented as an accurate experimental method for the analysis of moisture transport in porous building materials. The technique has evolved from the better-known medical technique. Compared to the commonly used gamma-ray and NMR-technique it has the advantage that it allows a fast and accurate determination of the two-dimensional transient moisture content profiles. A calibration procedure is presented to determine the optimal sample thickness for the visualisation of moisture in porous building materials. To illustrate the capabilities of the X-ray projection method, examples of water imbibition in homogeneous, heterogeneous and cracked building materials are included.