Quantitative measurements of moisture transport in building materials by quasi-real-time neutron radiography

Neutron radiography (NR) is a useful non-destructive method for detection o f moisture and of other hydrogenous materials (for example hydrophobic agen ts) in laboratory samples of porous building materials. Monitoring of relat ively fast (1 mm/min) processes of moisture transport in porous building ma terials is enabled by quasi-real-time NR methods based on novel imaging pla tes neutron detectors. Hydrogen content is determined by neutron beam trans mission analysis. The spatial resolution of this NR technique is 0.05-0.2 m m and detection sensitivity is 0.3 wt % H2O. Quantitative method was calibr ated by a series of standard porous samples with known moisture content. Ti me-frozen images of advancing waterfront in porous samples can be recorded with time resolution of 1-40 s. NR imaging techniques in quasi-real-time and quantitative neutron transmiss ion analysis have a practical value for applications in the building materi als and ceramic industries. The verification of the efficiency of various h ydrophobic treatments and coatings applied to porous building materials, st udy of application processes of hydrophobic agents and of various moisture transport phenomena in research on various effective hydrophobic materials are typical routine problems of interest for the building materials industr y and in civil engineering.