The experimental test for the evaluation of protective treatments: a critical survey of the Capillary Absorption Index

One of the most effective methodologies for the evaluation of the penetration of water into the bulk of stone materials is the capillary absorption measurement. In this paper the Authors would like to propose a short theoretical presentation of the two new parameters - the ICa (Absolute Capillary Index) and the ICr (Relative Capillary Index) - for capillary measurements recommended in the Italian Protocol Norma UNI 10859 “Cultural Heritage – Natural and artificial stones – Determination of water absorption by capillarity”. Definitely, the aim of this paper is to offer a powerful instrument to enlighten the utility of the proposed measurement methodology, both from a theoretical and practical point of view, and, finally, to help the interpretation of the experimental data through the use of the “capillary absorption index”