Assessment of the impact of high temperature on the facing stone from hard rocks
Journal Title: Вісник Житомирського державного технологічного університету. Серія: Технічні науки - Year 2019, Vol 83, Issue 1
Abstract
Samples from two deposits of natural stone, which are located in Ukraine, were experimentally studied. Tests of granite samples were carried out at high temperatures of 300, 500, 700, 900 °C. All presented samples show the change in surface colour at a temperature of 300 °C and above. The behaviour of heated granites depends on their mineral composition, structure and texture. The surface of all the prototypes are lighter, some samples of granites have lost saturation of colors. When the samples were heated to 900 °C of natural stone, the largest growth of the component L (images of the samples of the stone brightens) of the CIELab colour system occurred in the samples of Buka gabbro by 44.4 %. The smallest growth of the component L occurs in the granodiorite by 28.6% when the samples are heated to 900 °C. In gray granites, redness appears when heated, which is mainly concentrated around mica and other minerals that are rich in Fe. The greatest change in colour was due to the transition phase of dark-coloured minerals (biotite and pyroxene) into polymorphic minerals. This gave the samples of granodiorites lighter colour because minerals change colour from black to gray or white. Shades of white were given by quartz, where white microcracks appeared when it was heated. Noticeable aesthetic damage to the surface of natural stone samples begins at temperatures from 300 to 500 °C. Thus, a fire with temperatures below this limit can be considered «safe» in terms of aesthetic damage, if we consider only the coefficient of heating of the fire and exclude ash and gases.
Authors and Affiliations
V. V. Korobiichuk, V. I. Shamrai, O. M. Sidorov, S. O. Zarutskyi
Comparative analysis of time series forecasting models effectiveness by means of a multi-criteria procedure on the example of financial indicators
In the course of the research, a program complex was developed for forecasting time series using models of different classes and analysis of their effectiveness. Known time series models, such as neural networks, fuzzy l...
The dynamic modeling of totality of a free unconnected machining tool for machine part surfaces in a vibration field
A nonlinear mathematical model was developed to describe the dynamics of a totality of free unconnected machining tool of machine part surfaces in a vibration field, taking into account the physical and mechanical proper...
Theoretical fundamentals and models of branding: accounting aspects
The article deals with the theoretical approaches to branding as the instrument for business management. The economic definitions of the concepts of «brand», «branding» and «trade mark» are made more precise. The brand f...
A stability analysis of stationary conditions of a wheeled vehicle of a non-linear model
Non-linear equations of turnability of a two-axle wheeled vehicle and an equation equivalent to the Pevzner equation for defining the whole set of stationary conditions of its model are derived. The advantages of the pre...
Modification of steel 35 HL surge current during crystallization
The method of electro steel melt modification 35 HL variable polarity current pulses with a duration of more 10-3s frequency within the 5–33 Hz, 5–24 porosity meanders, strength 30–40 A at a voltage of 180–240 V during c...