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Material Technology
Asphalt
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Asphalts – origin and manufacturer
Binding agent produced from coal (coal tars, pitches, etc.,)
Produced from crude oil
Asphalt Cement: a dark brown or black colored bituminous materials used for hotmix asphalt
Asphalt is viscous materials, means that exhibits both viscous and elastic behaviour
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Asphalts – origin and manufacturer
Asphalt (Europe & North America)
It is means a mixture of bitumen and mineral aggregates, such as rolled asphalt, mastic asphalt, gussaphalt)
Asphalt (North America) is bitumen
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Production of Petroleum Asphalt
Basic Type of Petroleum
Asphaltic Base Crude Oil
Paraffin Base Crude Oil
Mixed Base Crude Oil
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Distillation Process
Distillation of petroleum is Fractional
Produce by Physical Process
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Production of Petroleum AsphaltSTRAIGHT RUN PROCESS Overheating Chemical changes
(Distillation process – under controlled)
TWO STEPS OF PRODUCT PROCESS Pumping process (crude oil to tube heater) Distillation process
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Atmospheric pressure distillation
De
cre
asi
ng
te
mp
era
ture
Naphtha
Gasoline
Kerosene
Diesel Oil
To further distilling and cracking processes
Series of traps to catch distillates
Path of GasLevel control of distillate
Schematic Cross Section of distillate trap
Hot topped crude (atmospheric residuum)
5000F high
pressure
Still tube heater
From storage
atmospheric pressure
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Vacuum steam distillation
5000F high
pressure
Still tube heater
Hot top crude
Series of traps to catch distillates
Partial Vacuum
Light vacuum distillate
Heavy vacuum distillate
Non volatile oils
Asphalt cement
steam
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The fractions of Petroleum
Fraction Product Type Boiling Point (0F)
Light Distillate Gasoline 100 – 400
Medium Distillate Kerosene 350 – 575
Heavy Distillate Diesel Oil 425 – 700
Very Heavy Distillate Lubricating Oil > 650
Residue Asphalt
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Chemical composition
Structure: High molecular-weight hydrocarbon CnH2+bXd (X = sulfur, Ni, O, trace-metal) (n = 25 – 150 atoms)
Composition(%): Carbon 80 – 87 Nitrogen 0 - 1 Nitrogen 9 -11 Sulfur 0.5 – 7 Oxygen 2 – 8 Trace metal 0 – 0.5
Affecting: boiling point, solubility, viscosity
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Molecular composition
ALIPHATIC: Paraffin – carbon atom linked in straight or brain chains
NAPTHENIC: Carbon atom are linked in simple-complex (condensed)
saturated rings
AROMATIC: Carbon atom are linked in especially stable benzene
rings
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Physical structure
100%
100%
100%
ASPHALTHENES
OILS
RESINS
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Constituent of A. C.
Phase Component C/H Ratio Contribution
Dispersion Oils < 0.4 Viscosity & Fluidity
Dispersed Asphalthenes > 0.8 Strength & Stiffness
Interfacial Resins -- 0.6 Adhesion & Ductility
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SOL TYPE SOL-GEL TYPE GEL TYPE
Asphalthenes are fully separated
Still bound, but not closely
Asphalthenes are discrete
Viscous fluid Elastic when load applied
Strongly bound in 3 D
No elasticity In nature – visco-elastic Elastic, in-elastic, permanent deformation
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Temperature
increased decreased glass transitionMore dissolve in resin
More dissolve in oilsLess viscous
Less soluble
Micelle bound in ordered structure
More viscous
FrozenRigid
Brittle
Visco-elastic solid
Properties of Asphalt:
Function of: (Temperature; Chemical Nature; Volume of Constituent)
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LIQUID ASPHALT
Cutback asphalt
Cutback Asphalt are produced by blending as asphalt cement with a hydrocarbon solvent
Classified as based on curing phase: RC = rapid curing (asphalt mixed with gasoline); MC = medium curing; (asphalt mixed with kerosene) SC = slow curing (asphalt mixed with diesel oil)
Grade range estimated based on viscosity) and types: RC range: RC 70 (70-100); RC 250 (200-300); RC 800 (800-1000); RC 3000 (3000-4000) MC range: MC 30 (30-40); MC 70 (70-140); MC 250 (200-500); MC 3000 (2000-6000) SC range: SC 70 (70-140); SC 250 (250-500); SC 800 (800-1600); MC 3000 (2000-6000)
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Cutback ASPHALT
Type Base Asphalt Cement Solvent Solvent Concentration (% volume)
Slow Curing (SC) Low viscosity
High penetration
DIESEL FUEL 0 - 50
Medium Curing (MC) Medium viscosity
Medium penetration
KEROSENE 15 – 45
Rapid Curing (RC) High viscosity –
Low penetration
NAPTHA/Gasoline 15 – 45
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LIQUID ASPHALT
Emulsified asphalt
Emulsified Asphalt are produced by breaking asphalt cement into very fine droplets or particles and dispersing these in a mixture of water and a surface active emulsifying agent. Two type of emulsified asphalt: anionic and cationic Classified based on setting time:
Anionic Emulsified Asphalt: RS = rapid setting: RS1; RS2 MS = medium settingMS2 SC= slow settingSS1; SS2
Cationic Emulsifed Asphalt: RS ; RS-2K; RS-3K MS ; SM-K; CM; K SS ; SS –K; SS-Kk
Specification for Asphalt Cement
Test
Penetration Grade
40 - 50 60 - 70 85 - 100 120 - 150 200 – 300
Min Max Min Max Min Max Min Max Min Max
Penetration test at 250C 100 gram, 5 sec 40 50 60 70 85 100 120 150 200 300
Flash point 0F (Cleveland Open cup) 450 - 450 - 450 425 - 350 -
Ductility at 250C, 5 cm/min, cm 100 100 100 100 100*
Solubility in trichloroethylene, % 99.0 99.0 99.0 99.0 99.0
Retained penetration after thin film oven test, % 55+ 52+ 47+ 42+ 37+
Ductility at 250C, 5 cm/min, after thin film oven test _ 50 75 100 100*
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Source: ASTM D946 Standard Specification for Penetration Graded Asphalt Cement for use in Pavement Construction
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Method of Testing Penetration
Specific Gravity
Ductility
Viscosity
Flash Point
Softening Point
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Penetration To measure the hardness or softness of a bitumen material under a
given set of condition The consistency test used to designate grade of asphalt cement Results (common used):
Pen 40 - 50
60 - 70
85 - 100
120 - 150
200 - 300
Test Reference: ASTM D5
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Penetration
100 gram
Asphalt Cement 770F or 250 C
= penetration in units of 0.1 mm
Load of 100 gram is applied for 5 second at 770F or 250 C
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Specific Gravity Reference: ASTM D70 (specific gravity and density of semi-solid bituminous
materials)
Procedures: The sample is heated until it can be poured The material is placed in a pycnometer The asphalt volume is determined by taking the difference between
total vol of the bottle and the volume of water required to complete the filling
Specific Gravity =
A=weight of pycnometer B = weight of pycnometer filled w water C= weight of pycnometer partially filled with asphalt D= weight of pycnometer plus asphalt plus water
(C – A)
(C – A) – (D – C)
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Ductility
Reference: ASTM D113 (Ductility of Bituminous Materials)
Procedures: The two ends of briquette specimen are pulled apart at a specified
speed and temperature in a liquid medium
The ductility is measured by the distance to which it will elongated before breaking.
Temperature test is 250C, elongation rate is 5 cm/minute
Total elongation is average at max 200 cm
The objective of test are: -adhesiveness; and –elasticity of asphalt
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Ductility Machine
Benang Aspal
Media Cairan – alkohol atau cairan garam
Klem
Gaya Tarik
Gaya Tarik
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Ductility Test Result
Panjang Sampel
Panjang Sampel + pasca penarikan
Daerah Putus
P kg
P kg
P kg P kg
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Ductility Affects
Adhession: The ability to stick to aggregate particles in the pavement Refer to the molecular force that exists in the area of contact
between unlike bodies
Cohesion: The ability to hold the particles firmly in place The molecular force that acts to unite the particles (cohesive
organization)
Ductile material has an excellent adhesive and cohesive properties
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Softening Point
Transition between solid to liquid
The higher the softening point, the less the temperature susceptibility
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Softening Point
Reference: ASTM D 36 – 66T (test for softening point of Asphalts and Tar Pitches
RING and BALL method
Heat is applied to raise temperature from 410 F at a rate of 90 F/min The temperature is read from a thermometer at the instant the
asphalt sample touches the bottom of a reference plate The temperature different between two balls do not exceed than
0.50 F
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Softening Point - temperature
asphalt
heat
asphalt
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Durability
Defined as the property that permits a pavement materials to withstand the detrimental effects of moisture, air and temperature.
Affected by i.e., mix design; properties of aggregate; properties of asphalt; and workmanships.
Method of test: -the thin film oven (ASTM D 1754); the rolling thin-film oven test (ASTM D 2872)
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Durability
Oxidation:
The chemical reaction which takes place when asphalt is exposed to the oxygen in air
It affect the hydrogen in the asphalt combines with oxygen in the air and is removed as water molecules.
The loss of hydrogen increases the carbon/hydrogen ration, increases the hardness of materials and loss of ductility and adhesion.
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Durability
Volatilization
Affected by temperature The process by which lighter hydrocarbons
evaporates from the asphalt Causes loss of plasticity in asphalt The rate of oxidation and volatilization almost double
for each 100C rise in temperature
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Solubility
Test reference ASTM D 4-52
To determine the amount of cementing agencies present This is useful for native asphalt To determine the amount of bitumen insoluble in naptha
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Flash Point
The flash point test are used to determine the temperature to which asphalt materials may be safely heated.
The flash point is the heating temperature at which the vapor pressure is high enough to give off sufficient hydrocarbon vapors to form an explosive mixture with air when contacted with open flame.
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Flash Point – temperature
Asphalt sample
thermometer
heat
gas
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Temperature Susceptibility
Asphalt will become harder (more viscous) with decrease in temperature and softer (less viscous) with increase in temperature.
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A and B are of identical viscosity gradeAsphalt B
Asphalt A
Temperature
Vis
cosi
ty
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NATURAL ASPHALT
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Types of Asphalts –binders – origin and manufacturer
Lake Asphalts
Rock Asphalt
TAR
Bitumen
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Lake Asphalts
Known as NATURAL Asphalt
Found in well defined surface deposits, such as located in Trinidad (discover by Sir Walter Raleigh – 1595)
Found in Venezuela, called as Bermuda Asphalt
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Lake Asphalts
Trinidad Lake Asphalt
The lake is approximately 35 hectare and 90 meter deep, containing about 15 million ton of material.
Assume as originated as a surface seepage of a viscous bitumen in lake Miocene times. Lowering of the earth’s surface led to an incursion of the sea and as a result deposited silt and clay over the bitumen.
Part of silt and clay penetrated the bitumen, forming a plastic mixture of silt, clay, water and bitumen. Subsequently the land was elevated above sea level, lateral pressure deforming the material into its present shape of a pseudo-laccolite.
Erosion remove the silt and clay covering exposing the surface of the lake.
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Lake Asphalts the composition
Trinidad Asphalt
30 percent water and gas 40 percent asphalt (soluble in carbon disulfide) 30 percent mineral matter
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Lake Asphalts the characteristics
Crude Trinidad Asphalt
Penetration at 770 F is range 1,5 – 4,0 Ductility at 770 F is 3 Solubility in carbon disulfide is 57 – 57 percent
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Lake Asphalts
Bermuda Lake Asphalt
The lake is approximately 445 hectare and 0,5 – 2,4 meter deep
Containing the largest deposits (volume still unknown).
Exuded ages ago through faults in the underlying rock strata
To remove the asphalts a dam is built of slag and waste and the water is pumped out, asphalt is dig out by hand and loaded into small cars.
The water is not thoroughly mixed with the asphalt.
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Lake Asphalts the composition
Bermuda Asphalt
60 percent asphalt (soluble in carbon disulfide) 3 percent insoluble non-mineral matter 2 percent mineral matter 30 percent water
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Lake Asphalts the characteristics
Crude Bermuda Asphalt
Penetration at 770 F, is range 20 – 30 Ductility at 770 F is 11 Non-uniformity is Nature Solubility in carbon disulfide is 92 – 97 percent
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Rock Asphalt origin and
manufacturer Formed by the impregnation of calcareous rocks
(limestone; sandstones) with seepage of natural bitumen.
The product can be mined (quarried) and contain approx. 12% mass bitumen
Asphalt content on the rock vary to a approx. 20%
Used as a mixture of the asphalt and the rock that contains it
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Rock Asphalt origin and
manufacturer The advantages:
It produces a non skid surface (often used as an anti-skid surfacing material)
It is uniform in quality
It is uniform in appearance
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Rock Asphalt origin and
manufacturer The disadvantages:
it sandy characteristic causes it to wear off easily and thus shorten its life cycle)
It is comparatively expensive (available only in a limited location
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Rock Asphalt other types Gilsonite: The deposit was found in Salt Lake City – UTAH – USA Found by S.H. Gilson Found in veins, more or less vertical and varying in width
from a fraction of an inch to 18 ft Commonly known as ASPHALTITES (asphalt which has
a high softening point) The color is not reflecting the hardness of asphalt,
generally color is relatively light
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End of Session
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TAR origin and
manufacturer
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Bitumen origin and
manufacturer