SOME CHARACTERISTICS OF BUILDING MATERIALS OF ANCIENT KYYIVAN MONUMENTS OF THE X-TH - THE XIІ-TH CENTURIES

The development of brickwork technique in ancient Kyyiv dates back to the X- th century. Old Rus` monuments’ masonry was made of large thin bricks called “plynfa” and lime-and-ceramic mortar. The size of the X-th – the XII-th brick sides varies from 27 to 36 cm, its thickness – from 2.5 to 4.5 cm. Different kinds of clay and loess extracted from the territory of Kyyiv and its vicinities were used as a raw material for brick and ceramic addition to mortar. That is why bricks in Kyyivan monuments differ in colour from light yellow to orange and dark red. Some gruss or cut straw were used as addition to fat clay. Limestone was brought to Kyyiv from Chernihiv area and lime mortar was produced in lime kilns situated near building sites. Ceramic addition to mortar called “tsemianka” was of refined clay, and crushed brick waste was used as well. Bricks were burnt under the temperature of 1000 – 1200 degrees C. That’s why bricks were very firm regardless of chink-like pores appeared as a result of hand-moulding of brick. The author took some investigation for the purpose to determine physical and mechanical properties of ancient bricks of Kyyivan monuments. Bricks were picked out of excavations or waste after building repairs. Small cubes were cut out of bricks with the height equal to brick thickness. Those samples were examined concerning their strength by compressing them perpendicularly to the sides the bricks were bedded in mortar. The strength of samples varied from 100 to 200-300 kg per sq.cm, water absorption was 10 % to 20 %. Some bricks taken from the Cathedral of the Assumption of Kyyiv-Pechersk  monastery were the most firm. The strength of those samples was about 400-500 kg per sq. cm, their water absorption was the smallest, about 5.6 %. Because of high porosity and water absorption of building materials the surface of ancient masonry was exposed to destruction under the influence of temperature overfalls and precipitation, as it can be seen on the open parts  of walls of the Old Rus` monuments. To prevent destruction of masonry, the walls of ancient monuments were covered with fine lime-and-ceramic mortar. Fragments of original plaster can be found on the walls of the XI-th century monuments St.Sophia Cathedral and St.Michael Church of Vydubychy monastery in Kyyiv. High level of well-developed building technique and high quality of building materials caused durability of ancient masonry and constructions in Kyyivan monuments, which preserved until nowadays.