Civil Engineering Reference
In-Depth Information
According to Asher Shadmon of the HABITAD centre in Nairobi:
'Stone is the building material of the future. We are on our way into a new
Stone Age. The resources are limitless and evenly spread over the whole
globe. Extraction does not require a lot of energy and does not pollute.
And most important of all is that the material is durable' (Shadmon,
1983).
A differentiation is usually made between loose stones and quarry stone. The for-
mer are found on beaches or in fields; the latter are deliberately quarried. Stone
primarily is used in the form of blocks, cut slabs or sheets, slate or crushed stone.
It is used to create the walls of buildings, retaining walls, edging and bridges.
Dressed stone and specially made slabs can be used for exterior or interior
cladding, framing around doors and windows, fireplaces, floors and stairs. Slate
can be used on floors, stairs, fireplaces, as framing around doors and windows,
as roof covering and as wall cladding.
Crushed stone or gravel is used as aggregate in various concrete structures.
Stone has a very high compressive strength and a low tensile strength.
Consequently, it is therefore possible to build high buildings of solid stone,
whereas a stone lintel has a very limited bearing capacity. The Greek Temple
shows this very clearly, where dimensions are immense just to achieve small
spans. In Roman aqueducts the stones form arches; the compressive strength is
thereby used at its maximum, making spans of up to 70 m possible.
The strength of stone varies from type to type. Slate has a higher tensile
strength than other stone and is therefore a good floor material on a loose under-
lay.
The art of building stone walls for protection against the forces of nature goes
back to prehistoric times. The earliest remaining stone buildings were built in
Egypt and Mesopotamia about 5000 years ago. Stone has been the only building
material used almost continuously until modern times, with its apotheosis dur-
ing the late Middle Ages when a widespread stone industry developed through-
out northern Europe.
The stone villages of this period were usually built with a foundation wall and
ground floor in stone; the rest of the building was brick. By the beginning of the
First World War the stone industry had lost its status, mainly due to the rapid rise
in the use of concrete. Large quantities of stone are still quarried and sawn into
slabs, mainly as marble in southern Europe, and a reasonable amount of slate
extraction still continues, but the dominant use for stone today is crushed stone
for concrete aggregate.
Many in the building industry anticipate a renaissance in stone building, even
if not quite as optimistically as Asher Shadmon. Façade cladding is seen as the
major area of use, because, with the exception of limestone and sandstone, stone
