A multi-analytical approach for pore structure assessment in historic lime mortars

Abstract Porosity of a mortar significantly influences its mechanical characteristics as well as durability. To ensure compatibility while designing a repair mortar for historic masonry, it is important to have both a qualitative and quantitative description of the pore structure. In this paper, we present the porosity investigations of two types of historic lime mortars by scanning electron microscopy (SEM), X-ray tomography (XRT), water sorptivity and mercury intrusion porosimetry (MIP). The overflow method is used to quantify the porosity from the frames/slices obtained from the SEM/XRT respectively. Different techniques measure different aspects of the pore structure and a comparison of results from different analytical methods allowed overcoming their specific limitations and achieving a better knowledge of the pore system of historic mortars.