Читать книгу Monument Future - Siegfried Siegesmund - Страница 347

This paper introduces a portable ultrasonic double-hole probe capable of recording changes in material properties along a depth profile and assessing consolidant penetration depth. Application of the device requires drilling two 20 mm holes of arbitrary distance in the surface layer of the masonry. The holes can be drilled directly into a continuous stone block or advantageously in the mortar joints between blocks, provided that appropriate contacts are achieved between the probe transmitter and receiver and the continuous stone. This moderately destructive method is useful mainly for conducting measurements on stone masonry façades or structures in which drilling holes, with subsequent repair, is acceptable. Consolidation assessment is demonstrated on quartz sandstone blocks in a laboratory as well as on a masonry wall made of the same ashlar blocks. The probe is fully compatible with ultrasonic laboratory equipment, e. g. UKS 12 or UKS 14 Geotron Elektronik.