Abstract
In considering water-rock interactions, it is fundamental to quantitatively estimate the mass transport and reaction in rock pore spaces. To address material transport, estimation of hydraulic conductivity is essential. On the other hand, to treat reactions (dissolution and precipitation of minerals and adsorption of dissolved matters onto minerals), evaluation of mineral-water reactive surface area is important. In the earth surface, the rock pores are not filled only with water but also with air. In such unsaturated condition, hydraulic conductivity and mineral-water reactive surface area may differ from water-saturated condition. Therefore we performed dissolution experiments using sandstone and evaluated the relationship between "water saturation", "hydraulic conductivity", and "mineral-water reactive surface area". As water saturation decreased, the hydraulic conductivity decreased but the mineral-water reactive surface area almost unchanged. We attribute this result to the existence of water films wetting mineral surfaces.
