Simulation experiment for weathering of culture relic on carbonate rock palisades in Longmen grottoes

In order to research the weathering mechanism on the surface of carbonate rock by condensation water in Longmen grottoes, in light of monitoring for condensation water and CO2 concentration on the spot, the weathering process is stimulated with a self-made indoor experimental tester that enabling stimulating temperature and humidity conditions, providing external source of CO2, and monitoring the reaction process. It shows that condensation water can dissolve the surface of carbonate rock, and that the mass loss and porosity of the rocks will increase when CO2 is added. Based on 78 tests, it proves that the mass loss of limestone sample is 0.077%~0.088% and the porosity increased from 0.39%~0.40% to 0.71%~0.74%; mass loss of dolomite sample is 0.032%~0.038% and the porosity increased from 0.61%~0.68% to 0.77%~0.85%; the average corrosion depth and velocity of limestone is 89.475 μm and 0.0956 μm/h, those of dolomiteis 36.865 μm and 0.0575 μm/h. It is concluded that the corrosive weathering is of great damage to the culture relic in Longmen grottoes. Key words: grotto; carbonate rock; condensation water; culture relic on palisades; weathering; simulation experiment