Some kinds of construction materials, notably rock is subjected to burning while producing construction materials. One of the materials is clay. The aim of the research is to ascertain if burning of clay rocks influences changes of specific and effective specific activity of natural radionuclides. The selected samples of clay were subjected to phasic burning. After each phase specific activities of natural radionuclides were establiched, and their effective specific activity was calculated. The undertaken research acquired data served a matter for further analysis and searching dependencies. The reserch results analysis having been made, it managed to establish, that there exists a correlation of different power degree berween burning temperature and specific activity. On the example of one of the clays researched there was drawn a polynomial regression pattern. When being aware of radiation characteristics and burning temperature of clay stock, the pattern will allow calculate radiation characteristics of the finished product. This will allow control (decrease) the radioactivity level of the finished product, i.e. ceramic materials and items.
Keywords: natural radioactivity, burning, clay rocks, radionuclide, correlation analysis, polynomial regression