Page 143 - New Trends in Green Construction

THE CHEMICAL TREATMENT OF NATURAL STONE INFLUENCES ON INFRARED SPECTRA
Volodymyr Shamrai, Antonio Rodero, Jose Maria Fernandez, José Ramon Jimenez, Valentyn Korobiychuk
Keywords: impregnating, natural stone color, natural facing stone, infrared spectroscopy of natural stone 1. Introduction
The influence of wetness, microorganisms, temperature and chemicals contributes to the destruction of natural stone. These factors lead to the reduction of strength and decorative indicators of natural stone. Currently, there are chemical impregnating agents for the protection and improvement of decorative properties that are widely used in the stone industry. The great numbers of chemical agents change the color indicators of a natural facing stone. The quality criterion of transparent chemical impregnating agents is the consistency of color after processing by these means. However, practical experience shows that color indicators also change after treatment with transparent chemical impregnating agents. Therefore, it is necessary to investigate the mechanism of their interaction with the natural facing stone using methods of spectral analysis and digital imaging processing.
2. Material and methods
During the study 18 samples of Bukivskyi gabbro (Galant) and 4 chemical impregnation agents were used.
Infrared spectrometry (IR) was performed in order to determine the structure of chemical impregnation agents and natural stone samples with different treatments. The IR spectra of natural stone samples were measured by an FTIR Bruker Tensor 27 spectrometer, scanning from 4000 to 250 cm−1 using the KBr as a reference sample in transmission mode (for study of chemical impregnation agents) and drift mode (to study the changes of natural stone samples after chemical and mechanical treatment).
3. Results and conclusions
In order to investigate the nature of the change in color coordinates after the influence of chemical impregnating agents, the method of IR analysis of chemical agents and natural stone samples (processed by chemical and mechanical methods) was used.
To determine the mechanism of influence of chemical impregnation agents, an IR spectral analysis of natural stone samples between mechanical and chemical treatment was conducted.
The absorption spectra of natural stone shown in Figure 1 demonstrate clear changes of absorption between mechanical and chemical treatments. At the same time, the absorption rate of chemically treated samples is much lower. The change of average values of absorption spectra of natural stone samples of the corresponding peaks of wavelengths depends on the type of processing.
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New Trends in Green Construction