湿度对盐溶液在壁画地仗中的毛细迁移影响研究

盐溶液在地仗中毛细迁移引起的盐分迁移、富集已成为壁画病害发生的重要原因。研究不同湿度条件下盐溶液在模拟地仗中的毛细迁移过程对可溶盐再分布的影响。分析不同湿度条件下毛细上升高度随时间的变化关系,含水率和电导率随高度变化关系,毛细饱和后试样表面变化情况及可溶盐含量随试样高度的分布。试验结果表明,空气相对湿度越低,毛细上升过程中水分向空气中迁移越多,水分难以向上迁移。试样的含水率随高度呈递减趋势,而电导率随试样高度增加而增大。可溶盐在毛细水上升过程中发生结晶分异,毛细前锋以NaCl结晶富集为主,亚前锋以Na2SO4结晶富集为主。其研究结果可以为壁画盐害的防治提供基础科学依据。

Research on effects of humidity on capillary migration of salt solutions in mural plaster

Salt migration and enrichment caused by the capillary migration of the salt solutions have been the important cause of mural deterioration. The soluble salt redistribution which influenced by the capillary migration of salt solutions in mural plaster under different humidities is studied. At the same time, the increase in height of capillary with time, water content and electrical conductivity distribution with height, specimen surface before and after capillary saturation under different environmental humidities, either the content of the soluble solution distributions with height after capillary migration are analyzed. The test results show that, the lower the air relative humidity is, the more water migration to air during the capillary rise is; it is difficult for water to move upward at the same time. The water content of samples with height decreases, but the electrical conductivity of samples with height increases. The crystallization of soluble salt in rising capillary water occurred. NaCl crystallization is enriched in capillary striker, Na2SO4 crystallization is enriched mainly in the second striker. The results of this study can provide a scientific basis for preventing and controlling salt damage of the mural.