Hydraulicity in historic lime mortars: A review

Abstract

Natural hydraulic limes were used in ancient times and are still produced today. A comparison of the chemistry and mineralogy of currently available NHL2 and NHL5 limes indicate that there are no clear differences except for the amount of 'undefined material', mainly comprising an amorphous phase. The chemical composition of these different limes is nearly identical. However, the classification of ancient hydraulic limes is mainly based on their chemistry, obtained from the analysis of ancient mortar binders. Moreover, it is shown that the phase composition of these limes evolves with time, making their classification uncertain and difficult. © RILEM 2012.