ULTRASONIC QUALITY INSPECTION OF DIMENSION STONE BLOCKS COMPACTNESS

The compactness of dimension stone blocks was previously controlled through various methods that were partially based on personal experiences, acoustic and visual observance of materials. With the development of technology, the ultrasonic pulse method is frequently used for the examination of stone test pieces and with an analysis of acquired data through the tomography method, the compactness is determined. The monolith stone blocks that are found at a site contain hidden discontinuities. The technique of data acquisition and the use of various instruments enable a good overview of the block interior. With an increased number of measurements, a suitable classification is prepared that helps reduce modification costs and increases the quality of stone blocks. The control methodology of compactness is based on the passage of longitudinal waves through the stone block without damaging the block during control. High differences in speed show irregularities in the material. With the observation system, we can prepare a tomography of the measured profiles that show us the locations of irregularities that should be observed more closely. During in situ measurements, the data for comparison with measured results are acquired. Determination of critical locations is of extreme importance before the processing of the block into smaller stone products or during the reconstruction of older stone elements or sculptures. The purpose of "in situ" measurements is to prepare a simple and fast method for the evaluation of materials compactness and for production work.