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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