Water uptake experiments of historic construction materials from Venice by neutron imaging and PGAI methods

We aimed at establishing a multidisciplinary procedure to characterize porous historic construction materials, whose properties (physical and mechanical, as well as chemical composition) can be affected by the presence and action of water content and salt ions. The whole procedure’s objective is to relate qualitative to quantitative information, to get an evaluation of the selected material’s mechanical properties. We developed a neutron-based investigation technique to assess the condition of historic buildings’ construction materials. Neutron radiography and tomography, as well as prompt-gamma activation analysis and imaging were applied to various types of stone blocks (which can be characterized e.g. with different levels of liquid permeability in saturated conditions) to detect the uptake of water and salt ions in porous construction materials of cultural heritage significance. The results enlighten the accurate water intrusion patterns, the evaluation of the water content in unsaturated conditions, the movement of water and salt contents inside the stone samples. The established methodology may find its application niche in the non-destructive assessment of historic and contemporary building construction materials.