Das Konservieren von Baudenkmalen: eine neue Methode, um die Wirksamkeit einer stein festigenden Massnahme nachzuweisen / The conservation of monuments: A new method to evaluate consolidating treatments

The degradation of monumental stones is the result of the interaction between the material and environmental factors, such as water, heat, atmospheric pollutants and living organisms. This interaction starts at the stone surface, progresses inwards and may reach several millimetres in depth. The common decay processes may lead to significant losses of the strength properties of the outermost layer of some stone materials which results in erosion, cohesionless appearance and disintegration. At present there is no method to measure stone hardness, both at the superficial surface and at larger depths (few centimetres), with the same sensitivity and reliability, which can be used both in laboratory and in situ. The aim of this paper is to present the application of a new methodology for measuring the Drilling Resistance (DR) of natural stones, by the use of the new portable system (DFMS) that can operate in the laboratory and in situ. The results obtained so far show that this new method is highly promising for in situ evaluation of the mechanical properties in order to assess the consolidating treatment applied for the conservation of monuments.