PRÓBA ZASTOSOWANIA MŁOTKA SCHMIDTA DO BADAŃ ARCHITEKTONICZNYCH CEGLANYCH MURÓW

The heretofore applied analysis of the sizes of bricks used for erecting walls, applied in architectural research and resulting in the establishment of groups distinguishing particular phases of the con-struction of a historical building, is, as a rule, effective and helpful for the determination of the relative chronology of successive stages of erection. It also made it possible to assume that the dimensions of the applied material, whose recognition in the course of the research is the simplest, are not the sole characteristic parameter that differentiates particular periods of the emergence of a given monument. Parameters just as essential for attaining this objective could involve also other physical features of the used building material In this instance, the parameter subjected to the test was the resilience of the bricks. The measurement, conducted in a non-invasive manner, tested the proposed method, which, if it fulfils all the expectations, will call for a precise approach. The applied examination of the wall surface involved the use of the Schmidt hammer, until now universally employed for examining concrete in contemporary buildings. This device serves the measurement of the reaction of the studied material to impact dealt with a constant force. The hammer in question is the Silver Schmidt produced by Proceq. The test was carried out in Łęczyca Castle, a relatively well-examined monument with accessible research amenities. The measurement was conducted in the castle courtyard. The experiment made it possible to ascertain a differentiation of the results of the research relating to particular fragments of the wall; in a confrontation with an analysis of the geometry of the examined bricks, they may be recognised as concurrent with the known and published stratigraphy of the castle walls. The experiment made it possible to assess the outcome as positive. A further examination of the usefulness of the suggested method for studying the reaction of the brick wall to blows dealt with the Schmidt hammer calls for consecutive tests involving monuments with a defined wall stratigraphy or carried out in the course of architectural research focused on monuments under examination. The proposed experiment can be also of use for establishing the relative stratigraphy of the walls of historical monuments located at a considerable distance from each other, since in view of the absence of direct proximity it is impossible to establish their usual chronological relation. In the case of successive positive results confirming the purposefulness of the proposed method, the latter will call for a more through outline. Its acceptance as useful for an absolute dating of brick walls, however, appears to be rather unlikely; quite possibly, multiple attempts at its application could allow the recognition of the outcome of the reaction of the bricks to the Schmidt hammer as a characterstic feature of brick walls from assorted epochs. One should also take into account similar undertakings while studying stone walls.