This document provides information on bitumen through a presentation by several people. It defines bitumen as a viscous liquid or solid consisting of hydrocarbons that is soluble in trichloroethylene. Bitumen is black or brown in color and has waterproofing and adhesive properties. It is produced from crude oil through fractional distillation. Different types of bituminous materials include tar, pitch and asphalt. The document also describes various tests conducted on bitumen like penetration test, ductility test, softening point test, and viscosity test. It provides recommended values for different bitumen grades based on these tests.
2. BITUMEN
“A viscous liquid, or a solid, consisting essentially of
hydrocarbons and their derivatives, which is soluble in
trichloro - ethylene and is substantially nonvolatile and
softens gradually when heated.”
“It is black or
brown in colour
& possesses
waterproofing
and adhesive
properties.”
3. PRODUCTION OF BITUMEN
Bitumen is manufactured from crude oil.
Bitumen is obtained as the last residue in fractional distillation of crude
petroleum.
The heaviest material obtained from the fractional distillation process is further
treated and blended to make different grades of paving grade bitumen
5. Types of Bitumen
•Tar and Pitch:
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.
6. 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
7. 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
8. Asphalt
• Cut back asphalts – those dissolved in mineral
solvents
Cutback asphalts are of three types
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
9. Asphalt
• Emulsion asphalts – those dispensed
or suspended in a water base
• Three types
Soap type in which soap is
used as the emulsifier
Clay modified soap type –
clay and soap are used as
emulsifier
Clay based type
• Advantages
Easy to handle
No heating is required
Good bonding to damp or
wet surfaces
10. BITUMINOUS TEST
• PENETRATION TEST
• DUCTLITY TEST
• VISCOSITY TEST
• SOFTNING POINT TEST
• FLASH AND FIRE POINT TEST
• SPECIFIC GRAVITY TEST
• SOLUBILITY TEST
• FLOAT TEST
• BINDER CONTENT TEST
11. PENETRATION TEST
AIM OF THE PENETRATION TEST:
To find out the hardness or softness of bitumen.
To determine the consistency of bituminous material
Grade of bitumen.
Apparatus required are
a) penetrometer
b) water bath
c) thermometer
The test carried out with a standard penetrometer with a needle
loaded with 100 gms,
13. PENETRATION TEST contd………
Procedure:
Soften the bitumen by heating (between 75 and 100oC). Stir it
thoroughly to remove air bubbles and water.
Pour it into a mould completely and level it.
Cool it at an atmospheric temperature of 15 to 30oC for 11/2 hours.
Maintain test temperature as 25 degree Celsius
Keep the container on the stand of the penetration apparatus
Clean the needle with benzene, &dry it
Adjust the needle to make contact with the surface of the sample
Adjust the dial reading to zero and note the initial reading
14. PENETRATION TEST
The needle is then released and allowed to penetrate into the sample
under the full action of the load.
The penetration at the end of time 5 seconds is measured .i.e final
reading
Difference of final &initial reading gives penetration value
Repeat the steps thrice.
Take the mean value & which becomes the penetration value of
bitumen.
16. PENETRATION TEST
The bitumen grade is specified in terms of penetration
value.
The bitumen of grade 80/100 means that the range of
penetration value of the material is between 80 and 100.
Depends upon the climatic conditions and type of
construction, bitumen are used.
17. IRC RECOMMANDATIONS
• Bitumen grades
a) 30/40,
b) 60/70,and
c) 80/100
• Hot climates -Lower penetration grades of
bitumen are preferred.
• Cold climate - higher penetration grades of bitumen are
preferred.
18. RECOMMANDED VALUES As per IS 73-2006
GRADES VG 10 VG20 VG30 VG40
Penetration
at 25”C,
80-100 60-80 50-70 40-60
19. DUCTILITY TEST
Aim:
• To measure the ductility of a given sample of bitumen
• To determine the suitability of bitumen for its use in road construction
The apparatus required for this test:
i) Standard mould (briquette mould)
ii) Water bath
iii) Testing machine
iv) Thermometer – Range 0 to 44oC, Graduation 0.2oC
PROCEDURE:
(i) Melt the bituminous test material completely at a temperature of 75°C
to 100° C above the approximate softening point until it becomes
thoroughly fluid.
20. DUCTILITY TEST
ii) Assemble the mould on a brass plate and in order to prevent
the material under test from sticking, thoroughly coat the
surface of the plate and the interior surfaces of the sides of the
mould with a mixture of equal parts of glycerin and dextrin.
iii) pour the sample of bitumen into the mould and level it using
straight hot knife
iv) After about 30-40 minutes, keep the plate assembly along with
the sample in a water bath. Maintain the temperature of the
water bath at 27° C for half an hour.
(v) Remove the sample and mould assembly from the water bath
and trim the specimen by leveling the surface using a hot
knife.
24. DUCTILITY TEST contd……
vi)remove the sides of the mould.
vii) Hook the clips carefully on the machine without causing any
initial strain. Adjust the pointer to read zero.
viii) Start the machine and pull clips horizontally at a speed of 50
mm per minute.
ix) Note the distance at which the bitumen thread of specimen
breaks.
Mean of two observations rounded to nearest whole number is
ductility value.
26. SOFTNING POINT TEST
• Aim:
To determine the softening point of bitumen.
• The apparatus required for this test :-
i)Steel balls-two numbers each of 9.5 mm diameter weighing 3.5 ±
0.05 g.
ii) Brass rings-two numbers each having depth of 6.4 mm. The
inside diameter at bottom and top is 15.9mm and 17.5 mm
respectively.
iii) Bath-heat resistant glass beaker not less than 85 mm in
diameter &1220mm deep.
iii) Thermometer – Low Range : -2 to 80oC, Graduation 0.2oC –
27.
28.
29. SOFTNING POINT TEST contd..
Procedure
The sample should be just sufficient to fill the ring. The
excess sample should be cut off by a knife.
Heat the material to a temperature between 75o – 100oC
above its softening point, stir until, it is completely fluid
and free from air bubbles and water
30. SOFTNING POINT TEST contd..
• If necessary filter it through IS sieve 30.
• Heat the rings and apply glycerin. Fill the material in
it and cool it for 30 minutes
• Assemble the apparatus with the rings, thermometer
and ball guides in position.
• After cooling for 30 minutes in air, level the material
in the ring by removing the excess with a warmed,
sharp knife.
31. SOFTNING POINT TEST contd..
• Fill the container with distilled water to a height
of 50mm above the upper surface of the rings. The
starting temperature should be 5oC
• With the help of a stirrer, stir the liquid and apply
heat to the beaker at a temperature of 5.0 ± 0.5oC
per minute.
32. SOFTNING POINT TEST contd..
• Apply heat to the bath and stir the liquid so that the
temperature rises at a uniform rate of 5±0.5oC per minute
• Record the temperature at which the ball touches the
bottom, which is nothing but the softening point of that
material.
33. Significance of softening point test
• Softening Point test is a very important test as it is a
fair indicator of melting properties of bitumen.
• Bitumen with lower softening point tend to melt on
the road in summer and start flowing under the impact
of temperature and traffic
• Therefore it can be concluded that bitumens with
higher softening point melt at higher temperatures and
have better rutting resistance
35. VISCOCITY TEST
• Its defined as fluid property of the material as resistance to
flow
• APPARATUS:
Tar viscometer, cup, valve, receiver, thermometer etc.
38. Significance of viscosity test
• Too viscous bitumen would result in inadequate and non-uniform
coating of the aggregates.
• Very low viscosity would again result in inadequate
coating as the bitumen will tend to bleed.
• Therefore viscosity at 135*C is a true reflection of the
quality of bond that is likely to be formed with the
aggregate.
39. Flash and Fire point test
• Flash point:-The flash point of a material is the lowest
temperature at which the application of test flame
causes the vapours from the material to momentarily
catch fire in the form of a flash under specified
conditions of the test.
• Fire point:-The fire point is the lowest temperature at
which the application of test flame causes the material
to ignite and burn at least for 5 seconds under
specified conditions of the test.
40. • Significance of flash and fire
point:-
for safety point of view this
tests are conducted, if bitumen is
heated beyond flash point it
catches fire ,therefore utmost care
is taken to see that heating is
limited to a temperature well
below the flash point and used
along the aggregates for the
construction of pavements.
41. Specific gravity test
• This test is done to determine the specific gravity of semi-solid
bitumen road tars. The principle is that it is the ratio of mass of
a given volume of bitumen to the mass of an equal volume of
water, both taken at a specified temperature.
• Apparatus :-
i) Specific gravity bottles of 50ml capacity
ii) Water bath
iii) Bath thermometer – Range 0 to 44oC, Graduation 0.2oC
43. Solubility test
• Pure bitumen is fully soluble in carbon disulphide and
carbon tetrachloride. If some quantity remains undissolved it
exhibits the quantity of inert mineral present in the bitumen.
Bitumen should be soluble in carbon disulphide at least
99%.
44. Float test
• The Float Test is used as a measure of consistency for
distillation residues. Residue from the emulsion is cast in a
tapered collar, and then it is allowed to float in a testing bath at
a specified temperature. The time, in seconds, between placing
the apparatus on the water and the water breaking through the
material shall be taken as a measure of the consistency of the
material under examination.
45. Significance of float test:-
The float value is one of the prime characteristics for identifying
"high float" asphalt emulsions. This high float characteristics
enables softer asphalt materials to remain in place on the roadway
without running off.
46. Impact test on Aggregate
Aim:
To determine the aggregate impact value
of given aggregates.
Apparatus required:
Impact testing machine,
cylinder, tamping rod,
IS Sieve 12.5mm, 10mm and 2.36mm,
Weight balance.
48. Procedure
• The test sample consists of aggregates passing 12.5mm
sieve and retained on 10mm sieve and dried in an oven for
4 hours at a temperature of 100oC to 110oC.
• The aggregates are filled up to about 1/3 full in the
cylindrical measure and tamped 25 times with rounded end
of the tamping rod.
49. IMPACT TEST Contd….
• The rest of the cylindrical measure is filled by two layers
and each layer being tamped 25 times.
• The overflow of aggregates in cylindrically measure is cut
off by tamping rod using it has a straight edge.
• Then the entire aggregate sample in a measuring cylinder
is weighed nearing to 0.01gm
50. IMPACT TEST contd..
• The aggregates from the cylindrical measure are carefully
transferred into the cup which is firmly fixed in position on
the base plate of machine. Then it is tamped 25 times.
• The hammer is raised until its lower face is 38cm above
the upper surface of aggregate in the cup and allowed to
fall freely on the aggregates.
• The test sample is subjected to a total of 15 such blows
each being delivered at an interval of not less than one
second
51. IMPACT TEST contd..
• The crushed aggregate is than removed from the cup and
the whole of it is sieved on 2.366mm sieve until no
significant amount passes.
• The fraction passing the sieve is weighed accurate to
0.1gm. Repeat the above steps with other fresh sample.
• Let the original weight of the oven dry sample be W1gm
and the weight of fraction passing 2.36mm IS sieve be
W2gm.
• Then aggregate impact value is expressed as the % of fines
formed in terms of the total weight of the sample.
52. Aggregate impact value
S.N
O
NATURE OF STONE AGGREGATE
VALUE
1 Exceptionally Strong < 10%
2 Strong 10% to 20 %
3 Satisfactory 20% to 30%
4 Weak for Road Surfacing >30%
53. AGING OF BITUMEN
• The physical and rheological properties of bitumen
change with time. It may become harder or less elastic.
Bitumen properties change over time on exposure to high
temperature and the atmosphere. This process is referred
to as ageing.
• Based on hardening or stiffening of asphalt material
1. short-term ageing.
2. long-term ageing.
54. 1. Short-term ageing
This occurs when bitumen is mixed with hot aggregates i.e.,
during production and construction .
2.Long-term ageing
This occurs after HMA pavement construction and is
generally due to environmental exposure and loading i.e.,
during the life of the pavement
55. Factors influencing bitumen Aging
1.Oxidation
2. Loss of volatiles
3. Steric or physical hardening
4. Exudative hardening
…. Time, Heat, Oxygen,
Sunlight
56.
57. • OXIDATION: The degree of oxidation is highly dependent on
the temperature, time and the thickness of bitumen film. Ageing
produces polar species that can form singles or multiple
structures
• LOSS OF VOLATILES :The evaporation of volatile
component depends mainly upon temperature and exposure
conditions.
• PHYSICAL HARDENING: It is strongly influenced by
aggregate-bitumen interactions. Directly after cooling, asphalt
sometimes appears to be soft as if it was still warm and a few
days later, the asphalt seems to have matured. This phenomenon
is called setting and is caused by slow physical hardening.
• EXUDATIVE HARDENING :Exudative hardening results
from the movement of oily components that exude from the
bitumen into the mineral aggregate
58. EFFECT OF DIFFERENT TYPES OF AGING ON BITUMEN
PERFORMANCE
• EFFECT OF THERMAL AND
ULTRAVIOLET AGING
• Consider three types of base bitumen from different sources
with the same penetration grade are taken as A ,B ,C.
60. TESTS ON AGING OF BITUMEN
Thin film oven test (ASTM D1754)
Simulates short-term ageing by heating a film of
bitumen in an oven for 5 hours at 1630C
61. Rolling thin film oven test(ASTM D2872)
Simulates short-term ageing by heating a moving film of
bitumen in an oven for 85 minutes at 1630C
62.
Pressure aging vessel (ASTM D6521)
simulate the effects of long-term bitumen ageing
that occurs as a result of 5 to 10 years HMA
pavement service
63. REJUVENATION TREATMENT
• Replace the oils lost and rebalance the bitumen
composition
• The controlling factor in rejuvenation is diffusion, to
ensure a positive result, the level of diffusion must be
controlled by careful choice of rejuvenator and the delivery
method.
65. Modified bitumen
• Modified Bitumen is a highly specialized blend of
bitumen with high quality polymer which is manufactured
under carefully controlled conditions in a “State of Art”
plant.
• Modified Bitumen is an exceptionally versatile product
with enhanced properties that makes it suitable for wearing
course application under special conditions like high
rainfall and high traffic areas
66. Advantages of Modified Bitumen:
Lower susceptibility to temperature variations.
Higher resistance to deformation/wear and tear.
Better adhesion between aggregates and binder.
Increase in fatigue life.
Resistance in low temperature cracking.
Better age resistance properties.
67.
68. Types of Modified Bitumen:
A variety of additives are used for modification of
Bitumen.
The degree of modification depends on type of
Modifier, its dose and nature of Bitumen.
The most commonly used Modifiers are:
Synthetic Polymers
70. Cost Benefit Analysis:
Since other components of the cost of construction
remains same except for the binder, the overall increase
in the cost of construction is approx. 15-25%.
However, the field trials have proved that frequency of
overlaying can be minimized and the maintenance cost
can be reduced to about 22-30% excluding the cost of
interest, safety and comfort to the road user.
71. Fatigue performance of bituminous mix
•It is phenomenon of fracture under repeated cyclic or
fluctuating load
• it is defined as no. of repetitions for which the initial
stress or strain changes by arbitrary factor.
72. Fatigue test
•A rectangular sample of bituminous mix is placed on
simple support and repetitive load is applied to the
sample, and sample is monitored till failure.
• Two cyclic loading is applied of equal magnitude P,
(separated by 1/3rd of the length of beam.)
• Test is conducted under two types of controlled
loading , namely controlled stress amplitude and
controlled strain amplitude
74. Fatigue performance of bituminous mix
The general expression for fatigue test result on bituminous mix is
given as
Nf=k1(1/ɛt)k2(1/Ed)k3
Where ,
• Nf =number of load applicable to failure
•Ed = dynamic modulus of beam
•K1 ,k2 , k3 = regression constant
Conclusion:-
The fatigue life of the mix for a given level of tensile strain is
higher if the stiffness modulus E of the mix is low. Thus ,
bituminous mixes with softer grade of bitumen, are expected to
have better fatigue life.
76. References:
• Influence of Bitumen Ageing on Asphalt Quality, Comparison Between
Bitumen and
asphalt aging ;research paper by Tahirou Moustapha
• Aging of bitumen Tan yi-qiu, Wang Jia-Ni1, Feng Zhong-Liang2 and Zhou
Xing , (2005). Influence and mechanism of ultraviolet aging on bitumen
performance.
• The Shell Bitumen Handbook ,By John Read, David Whiteoak
Editor's Notes
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The ageing of bitumen then leads to deterioration of pavement Bitumen must be resistant to change in properties over time. The amount and rate of ageing depend on many factors like temperature, exposure to oxygen, UV light, chemical composition and structure of the bitumen, etc.
Short term aging is more significant than long term aging.it occurs during storage transport mixing and placing.oxidation will happen
Oxidation ,
Shell Bitumen Handbook reported up to 15 different factors that influence bitumen ageing have been identified
Hardening due to oxidation has long been held to be the main cause of ageing. like Polar hydroxyl, carbonyl and carboxylic groups are formed, resulting in larger and more complex molecular which make the bitumen harder.
Penetration grade bitumen is relatively non volatile and therefore the amount of hardening resulting from loss of volatile is fairly small.
Physical hardening occurs at ambient temperature and is usually attributed to the reorientation of the bitumen molecules
Hardening as a result of exudation can be substantial when both the exudation tendency of the bitumen and the porosity of the aggregate are high
Because of the differences in air composition and the length of the solar radiation path between plateaus and low-altitude plains, plateaus(flat-topped hill) have unique climatic and environmental features due to their more intense radiation, longer daylight hours, and especially their much higher UV percentage, which ranges from 20% to 25% of the total solar light.
This is five times more than that on plains. Such intense UV radiation causes serious aging of bitumen, which influences its performance. As a result, the durability of the pavement decreases. Therefore it is important to study specifically the influence of UV radiation on
bitumen performance.
After UV and Thermal aging penetration and ductility value decreased while softening point is increased.
Rolling thin film oven test,Pressure aging vessel
method for measuring the combined effects of heat and air on a thin
moving film of bitumen. The test simulates the hardening that binder undergoes during mixing in
an asphalt plant. A moving film of bituminous binder is heated in an oven to a specified
temperature for a given period of time with a constant supply of air. The RTFOT also provides a
quantitative measure of the volatiles lost during the ageing process.
so it is no longer brittle
It would require sophisticated extraction testing and remodelling of binder in the road.
Rejuvenation needs to be contact with the aged binder , ability to penetrate this binder. CALL KAUSHALENDRA