Blown Bitumen 75/25 or Oxidized Bitumen or Blown
Asphalt is produced by blowing hot air into the
penetration bitumen. This action makes the
bitumen more rubbery than its original formula
and it becomes harder bitumen. This bitumen
recovery the weight loss under heating. Due to
low thermal sensitivity, the softening point is
much higher than regular bitumen and the
penetration index (PI) is higher than road
construction bitumen (8>PI>2) due to the
letter has a gel-like structure because of
asphalt accumulation. Blown Bitumen 75-25 is
Semi Solid grade of pure petroleum bitumen.
Special physical properties of its grade can be
used in different applications in the
construction business.
Blown Bitumen 75/25 is produced by the
air-blowing of penetration grade bitumen. This
is done at high temperatures, resulting in a
material of a much higher penetration index.
RAHA Bitumen 75/25 is based on petroleum bitumen
which is made by blowing bitumen 60/70 by very
hot air. The designation of the Blown Bitumen
75/25 refers to the midpoint of the softening
point acceptance criteria.
RAHA Bitumen 75/25 is produced by either
Continuous or Staggered Blowing Process. Heated
Penetration Grade Bitumen under controlled
environment is blown with air which controls the
Oil Content in the Bitumen while it oxidized.
The different grades for suited applications
produced are designated by two numbers to
indicate the mid-points of their softening point
and penetration ranges.
As said before, Blown Bitumen 75-25 is based on
petroleum bitumen which is made by blowing
bitumen 60/70 by very hot air. In addition, the
numbers relate to the midpoint of the material’s
softening point and penetration respectively.
The softening point value measured by Ring and
Ball method as determined by ASTM D36. Also, the
penetration value is in 1/10 mm as determined by
IP49 or ASTM- D5.
RAHA Bitumen Co. is also capable of producing
other grades of Oxidized Bitumen according to
the specifications of individual clients. Some
of the major advantages of Oxidized Bitumen are
that it is completely water resistant, highly
flexible and durable. Further, it is chemically
very stable. Oxidized bitumen is a very flexible
compound that is not only chemically stable but
also a very durable compound apart from being
completely water resistant. Lastly, Oxidized
Bitumen has some very prominent technical
advantages that makes it a very sought after
compound in various applications.
Uses of Blown Bitument 75/25
Blown Bitumen 75/25 is a solid or semi-black
solid material and gradually liquid when heated.
Oxidized Bitumen grades are blown or oxidized
Asphalt ‘s which are produced by passing air
through soft bitumen under controlled
temperature conditions. This process gives the
bitumen more rubbery properties than penetration
or hard grade bitumens and a variety of uses in
industrial applications. These grades are
suitable for sealing saw cuts and joints where
there is expected to be the minimum amount of
moving in the joint. Their wide temperature
range prevents bleeding in high-temperature
applications. They can also be used for
industrial applications such as pipe coating,
roofing, waterproofing, flooring, mastics, sound
damping, carpet backing, adhesive and electrical
applications. Hard bitumen under controlled
temperature conditions is widely used as an
anti-slip layer compound in the piling industry,
for the manufacture of roofing felts, the
roofing and waterproofing industries, for sound
dampening felts and under carriage sealant in
the automotive industry, electric cable joint
protection, joint filling compound, sealant
compound, and many others. Also used in sealing
saw cuts and joints where expected movements are
minimum.
Technical Advantages of Blown Bitumen 75/25
Durability
Flexibility
Water Resistant
Chemical Stability
Compared to paving grade bitumen:
Reduced temperature susceptibility
Exhibits a more ‘solid’ nature at ambient
temperatures
High penetration index
Recommendations for Handling / Storage
Heating of packaged bitumen is a critical phase
in most of the final uses. Typically, the
packaged material is heated and melted in
boilers out on site.
However, control at the heating phase is very
important in terms of health and safety as well
as in maintaining the quality of the product.
Note must be taken of the maximum safe handling
temperature of 230 C and this should not be
abused. Bitumen is a poor conductor of heat,
consequently, control of the heating phase is of
paramount importance.
The Oxidized Bitumen material should be broken
up prior to placement in the boiler. This
exposes a larger surface area to the heat and
encourages a more even heating regime. Without
the larger exposed surface area, aggressive
heating at the base and sides of the boiler may
well result in localized overheating, altering
the characteristics of the RAHA modified bitumen
and potentially causing thermal cracking of the
bitumen, creating the release of low lash
vapors. The flash point of the oxidized bitumen
then becomes irrelevant; as these low flash
vapors determine the fire risk. Melted
bitumen should not be left in the boiler and
reheated from cold, as there is then a high
potential for localized overheating around the
heating area (lack of convection means poor heat
transfer) and potential development of a
pressurized pocket of low flash vapors. Be
aware of the placement of any temperature
monitoring or control devices. As a result of
the poor thermal conductivity of the bitumen, a
thermometer in the bitumen some distance from
the heat source could read significantly
different (even hundreds of degrees) from the
true temperature of the bitumen near the heat
source.
Health & Safety
Workers should wear protective masks, gloves,
and goggles during application. The asphalt can
be removed from equipment and tools with
kerosene or gasoline. Care should be taken when
heating Blown Bitumen 75/25 to avoid
overheating. For Health and Safety information,
please make reference to the relevant MSDS.
Application of Blown Bitumen 75/25
RAHA Bitumen 75/25 is produced by either
Continuous or Staggered Blowing Process. Heated
Penetration Grade Bitumen under controlled
environment is blown with air which controls the
Oil Content in the Bitumen while it oxidized.
The different grades for suited applications
produced are designated by two numbers to
indicate the mid-points of their softening point
and penetration ranges.