High-speed thermal neutron tomography for the visualization of water repellents, consolidants and water uptake in sand and lime stones

Water repellents are intended to prevent or reduce water penetration into stonework and therefore minimize the rate of decay. Consolidants are intended to strengthen weakened stone and slow the rate of surface loss by binding loosened grains. To study the behavior of these fluids in stones is of great importance to geologists, architects and construction engineers. High-speed thermal neutron radiography and tomography are the ideal tools to study these dynamical processes on-line provided that the neutron beam flux is high. In the article we present the result of the visualization of fluid uptake stones in 3D, measured at the tomography station at the ILL, where currently the highest flux in the world is available for neutron imaging. The article presented deals with two important scientific challenges. The first is to develop a visualization tool for the inspection of fluid penetration in porous materials, while the second challenge is the three-dimensional visualization of dynamic processes by means of tomography.