Yungang Grottoes Black Stone Surface Dirt And Its Clear

Serious black pollution diseases have developed in the statues'surfaces of Yungang Grottoes because of natural factors and the anthropogenic effect in thousands of years'preservation process. This kind of pollution diseases not only influence on its artistic value, moreover, it may also be a hidden dangerous factor to the statues during the long-time direct contacting. In this paper, we reviewed the related researches recently about its production mechanismes, research techniques and cleaning technology of black pollution diseases phenomenon in stone relics'surfaces worldwide. Based on the frontier theories, three aspects of studies are carried out in view of the black pollution diseases. Investigation and study about the main disease types, especially their distribution, compositions and origins of black pollution diseases existing in the sculptures'surfaces were completed firstly. Then three cyclic tests, namely dry-wet cycling reaction, SO2 corrosion reaction and dry-wet with the SO2 together corrosion reaction, were carried out to study the effect of black pollution material of dust particulates and smoke layers on sandstone under different influencing situations. The experimental results showed that the dust particulates promote the sandstone destruction in a certain extent, while the smoke layers decreased its decay to a certain extent. As a result, here we suggest that the black pollution disease derive from dust particulates must be cleaned, while the smoke layers may be preserved during the cleaning practice, without considering its artistic effect. At last, some cleaning agents were selected to clean the black pollution disease.