What does the specific ratio of 1:2:3 mean?

The formula of wet concrete for rammed earth wall is usually red loam, lime and sand = 1: 2: 3. The soil material of wet concrete requires no dry soil, but it should not be too soft to avoid deformation after tamping. Generally, the acceptance of the moisture content of wet concrete is "hold it in your hand and sprinkle it on the ground", and the lime in wet concrete is appropriate.