Читать книгу Monument Future - Siegfried Siegesmund - Страница 414

The results of the investigations on the objects have shown that, at least in some areas, there is a correlation between the surface hardness measurements and the ultrasonic velocity. In these areas a structural damage can be assumed with low values.

Both values can be positively influenced by consolidation. The intensity of weathering apparently also plays a role here. With heavily softened objects such as tombstone III, the results can be interpreted to mean that the consolidation was only 268partially successful in some areas. If necessary, the amount of consolidant used was not sufficient.

Figure 8: The three tombstones after restoration with the hot lime reaction mortar.

Figure 9: The ultrasonic velocity correlated with the surface hardness of the three tombstones before conservation.

Practical consolidation measures on stone objects can be checked with the presented examination methods. They can provide valuable information on the success or failure of the consolidation method used and are therefore suitable as a control or quality inspection procedure.

The results of the salt reduction showed that there is a clear correlation between the level of electrical conductivity and the intensity of the weathering. This leads to the assumption that salts are primarily responsible for the weathering observed. The intense weathering on tombstone III is probably also due to the high hydric dilatation of the rock material. Clay minerals are probably responsible for the latter, as further investigations should clarify.