Chemistry Reference
In-Depth Information
Building mud, a composite material, is easily prepared by mixing clay or
clayey soil with fibrous matter, such as straw or dung of herbivorous
animals, and sufficient water to obtain a plastic, pliable mass. In ancient
Egypt, for example, mud was made by mixing clayey soil with sand,
chopped straw, and sufficient water so as to make the mixture pliable and
suitable either for use as mortar or stucco or for making bricks.
Mud Brick.
Bricks
are small, usually rectangular blocks of sun-dried or fired
mud or clay, used in building. Making bricks is probably one of the most
ancient technologies: mud bricks (see Fig. 32) have been made for at least
6000 years by molding a mixture of wet mud and fillers such as straw, leaves,
or dung into rectangular units of regular size that are then dried in the sun.
Mud bricks, also known as
sun-dried bricks
or, using the Spanish name,
adobe
bricks
, are quite hard, compact, and stable. After drying in the sun, if mud
bricks are fired at relatively high temperatures, generally below 850°C,
fired
bricks
are obtained (see Chapter 7) (Prandtstetten 1980; Brown and Clifton
1979, 1978).
Digging, collecting, and mixing the raw materials and then molding and
drying the shaped mud are the main stages involved in making sun-dried
brick. The dug-out clay, sometimes exposed for some time to the atmosphere
FIGURE 32
Mud brick.
Mud brick, first century
C
.
E
., Jerusalem, Israel. Mud brick, also
known as “adobe brick,” is a type of brick used in dry, hot climates. It is made by
mixing soil, which consist mainly of clay, with some form of fibrous matter such as
straw, leaves, or animal dung and sometimes, also comminuted stone. Adding water
(generally just below 20%) to such a mixture results in a workable mixture that is then
poured into regular and usually rectangular molds and left to dry under the sun. After
the water evaporates, a strong and durable composite material is formed in which the
clay particles are bound to the fibrous matter or/and gravel. Mud brick is still used, as
of old, in many developing areas of the world.
