Rammed earth is traditionally made from the soil the
building stands on, and this remains a preferred solution. In many places in the world this remains the case,
and this allows substantial buildings to arise where vehicles and even
the roads they need travel on are in short supply. The Kasbahs of
Morocco, the Dzongs of Tibet, the barns of central France and the
Great Wall of China were all built from the ground they stood on.
So for these buildings there is only the matter of
mixing to consider. Unless of course the material could be improved
with the addition of material from near or far. This might be the
addition of one of the basic ingredients, clay, sand or stones. Or it
might be that for some reason burnt lime, bitumen, blood, casein or some other
'exotic' might be added.
Mixing is either manual or mechanical, both can be
highly effective, both can be poorly done, both can use more energy
than is strictly necessary. Given the mass nature of the material
doing anything more than is necessary should be avoided
Manual mixing can be done with a shovel, spade or
highly effectively with a hoe. It may be that if you are extracting
the material on site how you dig can also help the material mix at the
same time, by digging across the face of a slope or 'cliff' rather
than sinking a hole or shaft. Using the landform to help extraction
can also be an effective way to mix.