Pore-structure and water transport properties of surface-treated building stones

This paper describes the details of a laboratory investigation aimed at ascertaining the effect of penetrating surface treatments on the micro-porosity and water transport properties of three building stones used in the construction of historic buildings and monuments within Europe. The pore-structure and morphology of treated and untreated stone specimens were assessed using a combination of helium autopycnometry, mercury intrusion porosimetry and scanning electron microscopy techniques. Water repellence and transport properties were evaluated using the Karsten tube and magnetic resonance imaging techniques respectively. It was found that surface penetrating treatments have a pore-refining effect on the stone matrix, the extent of internal alteration being dependent on the initial pore-structure. A treatment efficiency index has been established for evaluating the performance of treated surfaces.