Building with earth - Gernot MINKE (1)

5 Rammed earthworks
5.1
5.1 Formwork for
rammed earth
5.2 Climbing formwork,
BRL (Minke,
1984)
On all five continents, rammed earth has
been well-known for centuries as a traditional
wall construction technique. In fact,
rammed earth foundations found in Assyria
date back as far as 5000 BC.
With rammed earth techniques, moist earth
is poured into a formwork in layers of to 15
cm thick, and then compacted by ramming.
The formwork usually consists of two parallel
walls separated and interconnected by
spacers (5. 1). This technique is called pisé
de terre or terre pisé in French; the Spanish
names is barro apisonado or tapial; and the
German words is Stampflehmbau.
Traditional rammed earth techniques are still
used in many developing countries. Refined
formwork systems and electrical or pneumatic
ramming reduces labour input significantly
and makes rammed earth techniques
relevant in some industrialised countries as
well. For ecological, and sometimes for economic
reasons as well, mechanised rammed
earth technology may be a viable alternative
to conventional masonry especially in those
industrialised countries where high standards
of thermal insulation are not required.
Many firms employ this technology in the
southwestern USA and in Australia.
In comparison with wet loam techniques
(see chapter 9), the shrinkage ratio of
rammed earth is much lower, and strength
much higher. In comparison with adobe
masonry (see chapter 6), rammed earth –
since it is monolithic – provides the advantage
of longer life.
Techniques for rammed earth wall and
dome construction are described in the following
sections. A special earthquake-resistant
bamboo-reinforced rammed earth technique
as well as rammed earth floors are
described in chapter 15.
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Rammed earthworks