Technical condition of brickwork of the Grado-Yakutsk Trinity Cathedral of the 18th-19th centuries

Abstract

In the permafrost conditions of Yakutsk, the preserved old stone buildings made of locally produced ceramic bricks are of historical and scientific value. One of the first brick buildings in permafrost conditions is the Grado-Yakutsk Trinity Cathedral, which is now 315 years old since the start of construction. The article presents the results of the brickwork survey, the main being the strength characteristics determined under laboratory and field conditions. To ensure objectivity in determining the strength of bricks and brickwork, in addition to crushing the selected samples with a hydraulic press, the impact pulse method and the ultrasonic method were used. Significant heterogeneity of the brick structure and density was confirmed by ultrasonic examination of the selected samples and impact pulse examination of the wall structures directly at the site. The percussion-impulse determination of the strength of the masonry and the mechanical determination of the strength of the selected samples confirmed the grades of the compressive strength: XVIII century bricks - M50, XIX century bricks - M75. Thus, the satisfactory technical condition of the brickwork for the restoration and reconstruction of the building is confirmed. The physical properties of the samples show that the open porosity of the brick of the XVIII century is 1.4 per cent greater than that of the brick of the XIX century. It should be recognised that the difference in the pore structure of ceramic bricks of different years is most likely due to the composition of the raw material charge and the technology of their manufacture.