Chemistry Reference
In-Depth Information
SECONDARY ROCKS
BUILDING STONE, BRICK,
CEMENT, AND MORTAR
4
There is no reliable evidence about the first materials used by humans for
the construction of dwellings, nor about the early techniques used for build-
ing them. It is reasonable to assume, however, that the first dwellings may
have been tents made from the branches and leaves of plants, rushes, reeds,
and/or animal skins. Developments in the form of settlement may have
brought about efforts to build strong, lasting living quarters that eventually
led to the use of masonry and, later still, of bricks consolidated with mortar.
The convenient general term
building materials
is used here to represent
natural and human-made materials whose principal use is for the construc-
tion of buildings, fences, roads, and other such structures. This includes
natural materials such as
stone
and
mud
as well as human-made
mortar
and
brick
. Building stone, mud brick, and the different mortars used to consoli-
date and cover them are the main subject discussed in the following pages.
Burned brick, a ceramic material, is discussed in Chapter 7 (Wright 1998;
Davey 1961).
4.1.
BUILDING STONE
Much building material has been derived from two
monomineral sedimentary
rocks
:
gypsum
(composed of hydrated calcium sulfate) and
limestone
, which
consists of
calcite
(composed mostly of calcium carbonate). Freshwater and
seawater contain dissolved calcium carbonate and calcium sulfate. Most
limestone and gypsum are formed when, as a consequence of the evapora-
tion of water, calcium sulfate and calcium carbonate precipitate out of the
water solutions as either gypsum or limestone. Limestone is also formed as
a result of the activity of living organisms. Many sea- and freshwater
animals, such as snails, clams, and corals, as well as some water plants, draw
