Study on deteriorarion mechanism and protective measures of historical stone monuments

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(1) Experimental apparatuses were developed to measure moisture retention curve and unsaturated hydraulic conductivity of brick and mortar. The moisture retention curve and hydraulic conductivity of brick and mortar used for historical brick buildings and monuments. The measured results showed that the water contein is higher for mortar than that for brick at a given water suction. The unsaturated hydraulic conductivity is higher for mortar than that for brick. The water regime of historical brick buildings and monuments was calculated with finite element method software using measured data.(2) Physical properties, such as grain size distribution, pore size distribution and specific surface area of stone, brick and compacted soil taken from historical sites were measured and related to the deterioration of the materials.(3) A thermo-TDR probe was developed to measure the water content, electrical conductivity and thermal conductivity. These sensors were used for brick and earthen wall. The measured data showed the validity of these sensors.(4) In order to study the deterioration mechanism of Japanese earthen wall, model earthen wall was build in Historical Village of Hokkaido. The TDR sensors were embedded in the earthen wall and the change of volumetric water content was measured. A numerical calculation of water content and water flow of earthen wall during the drying process was carried out with meteorological data, material data of soil by DELPHIN4 program developed by TU Dresden. The calculated results corresponded well with the measured ones. These results showed the validity of DELPHIN4 program for determining water content in the porous materials. Since it is necessary to use non-destructive method to obtain physical properties of the cultural properties, the simulation technique is quite effective for these studies related to the conservation of cultural properties.