This report is concerned with the relation between the eluviation which is one of the important action of chemical weathering and the change of physical properties of rocks. The author carried out the experiment in which two types of mudstone containing calcite were used as a sample and eluted by acetic acid.
Then he compared the physical properties of mudstone before and after the elution of calcite.
The most remarkable change of physical properties with the elution of calcite results in the mechanical quantity such as compressive strength and the like, dry shrinkage ratio and porosity. Shore hardness and unit weight are next to these properties. Specific gravity is less changeable.
The change of physical properties can be classified into two types. One of these is the change related to the calcite content. The change of porosity, unit weight and specific gravity correspond to this type, which is remarkable for a large quantity of calcite at the initial condition. Another type is the change related to the state of calcite in the mudstone. Compressive strength and dry shrinkage ratio belong to this type. In this case, the extent of change depends on a role which the calcite has been playing in the texture of mudstone before the elution.