Abstract
In the Asian countries, there are many important wall paintings on earthen walls of temples and other historical buildings. Because earth can be considered as a porous material, there is water redistribution in the walls due to the change of the surrounding environmental conditions. Water evaporates under dry conditions from the wall surface and salts accumulate near the surface zone and can cause salt efflorescence damages in the wall paintings. In order to develop suitable protective measures, it is necessary to know the water content profiles and water movement in the earthen walls. For this purpose, a model earthen wall has been built up in the historical folklore museum in Sapporo. The water redistribution in the earthen wall was measured by using a TDR (Time Domain Reflectometry) apparatus. The numerical simulation of water movement in the model wall was performed with the Delphin4 program developed by the TU Dresden. The material data, such as moisture retention curve, liquid water conductivity and water vapor diffusivity of the model earthen wall and climate data of the location Sapporo were taken into account for simulation. For development of suitable protective measures, it is quite important to have non destructive methods to understand the water regime in porous materials. The good agreement between simulation results and measured moisture profiles in position and time show the validity of using the Delphin4 program for development and evaluation of conservation measures of historical buildings and stone monuments.
