BUILDING MATERIALS
Introduction
Engineering Structures are composed of materials. These materials are
known as Engineering materials or building materials. The service conditions of
building demand a wide range of materials and various properties are to be
properly studied before making final selection of any building material for a
particular use. It is necessary for an engineer should have working knowledge
of properties and manufacturing process of such materials.
Engineering materials
are available from natural sources. They can also have manufactured.
Engineering materials obtained from nature have properties which cannot be
easily altered Artificial engineering materials may be manufactured in such a way
that possess the desired properties.
Classification of materials - Based on their use
The
materials of construction can be broadly classified as:
1. Stones
2. Bricks
3. Clay
products
4. Lime
5. Cement
6.
Mortars
7.
Concretes
8. Timber
& wood based product
9. Metals
10.
Plastics
11. Glass
12.
Paints, Varnishes & Distempers
13.
Asbestos
14.
Asphalt & Bitumen
Properties
Properties for various
materials have to be obtained for the purpose of specifying them for particular
use. Properties of materials are mainly classified as physical, chemical, and
mechanical. Properties of materials are used for economic constructions and
safer design of engineering structures
Physical Properties of materials
The
effective use of any building material requires the knowledge of its physical
and mechanical properties and the basic properties of building may be placed
into several groups.
1.
Density
2. Bulk
density
3.Specific
gravity
4.
Porosity
5. Water
absorption
6. Water
permeability
7.Chemical
resistance.
8.
Weathering resistance
9. Fire
resistance
10.
Thermal capacity
11.
Durability
Density
The density of a material is defined as its mass per unit volume of homogeneous material.
Bulk density
Bulk density is defined as the
weight per unit volume of a material in a natural state, including porous and
voids.
Specific
gravity
Specific gravity is defined as the weight of unit volume of material in
an absolutely dense state, without porous on voids. It may also be defined as
the density of the material divided by the density of water.
Porosity
Porosity is the ratio of the volume of voids to the total volume of a
material sample, generally expressed as a percentage.
Water Absorption
Water absorption refers to the
ability of a material to absorb and retain water in the porous. it depends on
the materials porosity, swellilng capacity, and water receptivity.
Water permeability
It is the properly of a material allowing water to pass through its
pores. It is important in the case of soils.
Chemical
resistance
It is the properly to resist the action of chemicals, acids, etc., is
known as chemical resistance.
Weathering
resistance
It is the property to resist nature like sun and rain is known as
weathering resistance
Fire
resistance
It is the property of a material to resist high temperature iş known as
fire resistance.
Durability
If is the property of material to destruct by natural agencies, like
alternate heat & cold, dissolved gases in rain etc.,
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