Civil Engineering Reference
In-Depth Information
Table 4.2: The physics of building materials
Structural
Climatic
Surface
Surface
materials
materials
materials
treatment
Weight
x
x
x
Compressive strength
x
(x)
(x)
Tensile strength
x
(x)
(x)
Thermal conductivity
(x)
x
(x)
(x)
Thermal capacity
(x)
x
(x)
Air permeability
(x)
x
(x)
Vapour permeability
(x)
x
(x)
(x)
Notes:
x: primary function
(x): secondary function
materials. The following technical specification can be of great help (see also
Table 4.2):
Weight indicates what structural loading can be anticipated in the building,
which building techniques can be used, etc.
Compressive strength is an expression of how much pressure the material toler-
ates before collapsing, and is of particular importance in the design of
columns and other vertical structural elements.
Tensile strength expresses how much a material can be stretched before col-
lapsing. This is important for the calculation of horizontal structural elements
and suspended structures.
Thermal conductivity describes a material's ability to conduct heat. It describes
the insulating properties that can be expected of this material as a layer with-
in an external wall, for example. The conductivity of a material is dependent
upon the weight of the material, the temperature, its moisture content and
structure.
Heat capacity of a material is its ability to store warmth, which tends to even
out the temperature in a building and also in many cases reduces energy con-
sumption. Heat capacity is strongly related to a material's weight.
Air permeability indicates how much air is allowed through a material under
different pressures. It depends upon a material's porosity, the size and the
structure of its pores. The moisture content of the material also plays an
important role, as water in the pores will prevent air passing through. The
right specification of material is particularly important when making a build-
ing airtight.
 
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