The manufacture of bricks for building purposes consumes large quantities of virgin materials, such as clay. On the other hand, the ornamental stone processing industry produces a huge amount of stone cutting sludge in its process. Therefore, this study presents the development of ceramic materials for the manufacture of bricks with stone cutting sludges, more specifically from granite. For this purpose, the physical properties of the stone cutting sludge and the chemical composition were mainly analyzed. Subsequently, different groups of ceramic samples were conformed and sintered with various combinations of clay and of stone cutting sludges. The conformed samples were evaluated with different physical tests and with the compressive strength test. The addition of stone cutting sludges to the ceramics reflected the creation of a material with lower density and higher porosity. The compressive strength of the different groups reflected a maximum allowable percentage of stone cutting sludges incorporation of 70%. Therefore, ceramic materials were developed with stone cutting sludges, developing a sustainable, lighter material with acceptable mechanical and physical characteristics. Avoiding the deposition of a polluting waste in a landfill and at the same time avoiding the extraction of new virgin materials.

Cluster analysis of fracturing in the deposits of decorative stone for the optimization of the process of quality control of block raw material

An important task of stone processing enterprises is decorativeness management of natural stone products. Among different ways to change the natural stone decorativeness parameters, stone polishing is the most common. Classification of the types of Pokostivskiy granodiorite of different hues is based on the characteristics of different types of stone after machining. However, information about the original color characteristics of stone blocks is needed for selecting the polishing technology. In the study of Pokostivskiy granodiorite blocks, the patterns of lightness changes in rough and polished samples of the types of Pokostivskiy granodiorite of different hues depending on the share of white minerals were identified. Before polishing, lightness and average share of white minerals for light, dark and very dark types of Pokostivskiy granodiorite are virtually unchanged. After polishing, lightness of different types of Pokostivskiy granodiorite changes respectively from 59.5 % to 69.4 % – for light types; from 59.0 % to 65.5 % – for dark types; from 58.8 % to 61.2 % – for very dark types. The developed method of determining the types of Pokostivskiy granodiorite of different hues using digital image processing will allow distinguishing rough blocks, different in lightness and hue, on stone processing enterprises. This will enable stone processing enterprises to select raw materials without prior processing and to choose the polishing technology for standardized products that are made of similar rocks.

Exploring the efficiency of applying fractal analysis for the process of decorative stone quality control

We report results of experiment on the estimation of decreasing strength of natural stone exposed to repeated dynamic loading. The study was conducted in order to assess the feasibility of using natural stone for the accompanying extraction of stone blocks under conditions of gravel quarries. We examined samples from 13 Ukrainian deposits of natural stone. The stresses were created by a weight dropped on the tiles made of natural stone. The damage was evaluated using the ultrasonic device UK-14MP. The established resistance of rock to repeated impact actions showed that at a low specific energy of the impact (1.47‒2.7 kJ/m³) there are the granites (Zhezhelivski, Tokivski, Koretski deposits) that are almost not destroyed. These very deposits are suitable for the accompanying extraction of blocks of natural stone under conditions of gravel quarries. Building structures from these fields can be used in facilities and buildings that are exposed to vibration. Depending on the energy capacity of destruction, we conditionally divided natural stone into three groups. By applying a nondestructive control, we found that granites lose their strength prior to destruction from 11.6 to 41.5 % because of anthropogenic microcracking. The fatigue strength of granites is affected by the content of quartz; an increase in quartz results in increasing strength. It is demonstrated that the texture of granite exerts not a less impact on the strength of the stone; an increase in grain size in granite leads, despite a considerable content of quartz, to a decrease in the stone fatigue strength. Increasing accessorial minerals in granites leads to a decrease in fatigue strength