Bituminous Materials
Bituminous Materials
 The term bitumen is a generic name applied to various mixtures
of hydrocarbons
 They may be gaseous, liquid, semisolid, or solid
 Most common materials within the family of bitumen’s are
tars, pitches, and asphalts
 Destructive distillation is carried out on natural materials
produces tar
 Partial evaporation or fractional distillation of tar produces
the solid or semi-solid residue of pitch
 Asphalts are dark brown or black solids or semi solids which
are found in the natural state and are also produced by the
refining of petroleum
 Some natural deposits of asphalts are found in Kentucky,
Utah, Colorado, and California
 95% of asphalt materials used in North America are derived
from the refining of petroleum
Test of Flow of Properties
 The viscous or flow properties of bitumen’s
are of importance, both at the high
temperatures encountered in processing and
application and at the low temperatures to
which bitumen’s are subjected in service.
Flow properties are complex, and as a result,
tests have been formulated to measure the
consistency of the materials at temperatures
comparable to those encountered during the
service life of the bitumen.
Test of Flow of Properties

The penetration test
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Are used to determine the flow characteristics
of asphalts in the range of temperatures used
during application
Flash Point Test
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Are conducted to determine the amount a
bitumen will stretch at temperatures below its
softening point
Viscosity Tests
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Measures the temperature degrees Celsius at
which a steel ball falls a known distance
through the bitumen
Ductility Test
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Viscosity Test
Softening point test
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Measures the depth of penetration in tenths of
millimeters of a weight needle into a bitumen
during a period of time at a given temp.
Indicates the temperature to which asphalt
cement can be safely heated without danger
of flash. A brass cup is partially filled with
cement and heated at a prescribed rate. A
small flame is place over the surface of the
sample
Thin Film Oven Test

Test is used to obtain a general indication of
the amount of hardening which may be
expected to occur in an asphalt cement during
the plant operation.
Penetration Test
Types of Bitumen’s
 Tar and Pitch
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Most of the tar and pitch used in construction
is made by the distillation of coal.
Tar is used to saturate felt paper and coated
kraft paper to produce a waterproof
membrane.
Coal – tar pitch oxidizes quite rapidly when
exposed to ultra violet rays of the sun.
Types of Bitumen’s
 Asphalt
 A large percentage of
the asphalt used
results from the
refining of crude oils
 There are three main
groups of asphalt
products produced
from straight run
asphalts
Asphalt

Hot asphalt- those soften by heat
 Hot asphalt can be used directly or it can be
processed further to produce a harder material
 Hot asphalts have good resistance to the
transmission of water and water vapor when they are
applied to dry surfaces and the heating process is
controlled
 Hot asphalts bond poorly to damp or wet surfaces,
have relatively poor flexibility, oxidize under the sun’s
rays and are brittle at low temperatures
Asphalt
 Cut back asphalts – those dissolved in
mineral solvents

Cutback asphalts are of three types
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Straight run asphalt and solvent
Heavily filled cutback made by adding a large
amount of filler and fiber to asphalt cut with
solvent
Primer type cutback asphalt in solution with no
filler or fiber
Asphalt

Emulsion asphalts – those
dispensed or suspended in a water
base

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Three types
 Soap type in which soap is
used as the emulsfier
 Clay modified soap type –
clay and soap are used as
emulsfier
 Clay based type
Advantages
 Easy to handle
 Addition water is all that is
necessary to decrease
viscosity
 Drying involves the loss of
water by evaporation
 No heating is required
 Good bonding to damp or
wet surfaces
Uses of Bitumen’s
 Waterproof coating and membranes
 Used to provide a waterproof coating for walls and to
make waterproof membranes in buildings
 Asphalt pavement
 Asphalt cutbacks and emulsions have their greatest
use in road construction
 Accounts for about 85% of amount produced in North
America
 Asphalts in pavements acts as a binder for the
aggregates, in this capacity as a cement, the asphalts
are usually semisolid
 Before it can be mixed with the aggregate the asphalt
must be made liquid by heating, and cutting with
solvent or by emulsifying with water
Uses of Bitumen’s
 Liquid paving asphalts
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Most of the liquid asphalts used for paving are cutbacks
Three types
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Gasoline used as a solvent rapid curing liquid asphalt
Kerosene – produces a medium curing asphalt
Heavier fuel oils produce a slow curing asphalt
Types refer to the rate at which solvent is lost, either during
construction or after pavement has been laid
The liquid asphalt to be selected for any given project depends on the
construction conditions
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In general a rapid curing grade can be used as a binder for open
graded aggregates that coat quickly during mixing or for surface
treatments
Medium curing grades are required for dense graded aggregates which
require longer mixing time
Slow curing grades are used with aggregates requiring a long mixing
time and for projects where the pavement may have to be torn up and
reworked from time to time
Uses of Bitumen’s
 Asphalt paving cements
 The binders for the more expensive asphalt
pavements are usually asphalt cements
 These semisolid materials are also separated
into grades having different ranges of
hardness
 Asphalt canal liner and bank erosion control
 The versatility of asphalt has led to its
employment in many types of hydraulic
structures
 Mixes made with the harder asphalts
Uses of Bitumen’s
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Asphalt shingles
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Asphalt shingles are made from heavy rag felt,
saturated with asphalt and coated with high
melting point flexible asphalt
Ceramic coated mineral granules are pressed
into the asphalt coating on the exposed face to
provide a fire resistant surface.
Built up roofing
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Built up roofing is term applied to a type of
roofing made by building up successive layers
of felt paper and asphalt over a solid roof deck
Five types

Type 1 – consists of asphalted felt
paper, asphalt and gravel or slag
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Type 2 – consists of tarred felt paper
pitch and gravel
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Type 3 – consists of asbestos felt,
asphalt felt and a smooth flood coat of
asphalt
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Type 4- requires heavy slate surfaced
roofing paper as well as asphalt
saturated felts
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Type 5 – called cold process – felts are
cold process felts saturated with cold
asphalt emulsion and the asphalt top
coating is applied cold.
Uses of Bitumen’s
 Rolled roofing
 Rolled roofing consists of very heavy asphalt saturated
felt paper, with or without finely crushed slate
embedded in one surface put up in rolls.
 Sprayed on asphalt roofing
 A new technique for the application of asphalt roofing
involves the use of special equipment for apply the
material
 A special gun with three nozzles and a fiber cutting
chamber is used
 Glass fibers are fed into the chamber where they are
cut to predetermined lengths and blown out through a
center nozzle
Uses of Bitumen’s
 Asphalt flooring
 Asphalt mastic flooring – is made by mixing an
emulsifed asphalt with Portland cement, sand and
gravel or crushed stone to form a plastic mixture. This
is spread over the floor screened compacted and
floated to a depth of ½ in.
 Asphalt tile – are composed of fibers bond together by
a blend of selected asphalt binders
 Fiberboard
 Insulation boards composed of asphalt impregnated
wood fibers used in built up roofing systems