BAHAN PERKERASAN MODUL ASPAL

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BAHAN PERKERASANMODUL ASPAL
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JENIS ASPAL

• Aspal / bitumen / asphalt cement (AC) /
  penetration grade adalah bahan pengikat (binder)
  bahan perkerasan yang mempunyai sifat utama warna
  hitam (umumnya) dan sensitif terhadap suhu.
• Jenis-jenis aspal
• Aspal bumi (fosil) atau bitumen
• Tars
• Aspal natural (Natural bitumen) aspal buton
• Biobitumen (aspal dari tumbuhan)

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BITUMEN MANUFACTURE

• Crude oil is refined by fractional distillation
  to separate gas, gasoline, kerosine, gas oil and
  long residue.
• The long residue is then redistilled under vacuum
  at 350-400 C to produce short residue.
• The short residue consist of many different
  grades of bitumen
• In many case, the vacuum residues are processed
  by air ratification (blowing) to produce harder
  penetration grade bitumens
• The harder bitumens can then be blended with
  softer bitumens to produce intermediate grades

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PROPERTY REQUIREMENT FOR PENETRATION GRADE BITUMEN

• Penetration at 25oC
• Softening point oC min and max
• Ductility
• Loss on heating for 5hr at 163oC
• - Loss by mass (max)
• - Drop in penetration (max)
• Solubility in trichloroethylene by mass (min)
• Permitivity at 25oC and 1592 Hz (min)

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CHARACTERISATION OF BITUMENS

• The behaviour of bitumen is complex.
• It is required a large number of tests to
  describe the properties of bitumen over a wide
  range of operating conditions (temperature,
  stress, strain rate).
• To simplify, the mechanical behaviour of bitumen
  is described using emperical tests and equations.
• The basic tests used are
• - Penetration test (low temperature range
  lt60oC)
• - Softening point test (low temperature range
  lt60oC)
• - Viscosity test (high temperature range
  gt60oC)

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PENETRATION TEST

• This is an empirical test
• To be approximately equivalent to a measurement
  of stiffness at a loading time of 0.4 seconds.
• The penetration is the consistency expressed as
  the distance in tenths of a millimetre that a
  standard needle, of 100g, will penetrate
  vertically into a sample of bitumen at 25oC in 5
  seconds.

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PENETRATION TEST
Digital
Manual
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PENETRATION TEST
Penetration in unit of 0.1mm
100g
100g
Aspal (25oC)
Aspal (25oC)
Start
After 5 seconds
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SOFTENING POINT TESTRing and ball test

• Two steel balls are placed on two discs of
  bitumen contained within metal rings. These are
  raised in temperature at a constant rate
  (5oC/min) in a water bath. The softening point is
  the temperature (oC) at which the bitumen softens
  enough to allow the balls enveloped in bitumen to
  fall a distance of 25mm and hit a plate.
• The softening point is approximately the
  temperature at which the penetration is 800,
  hence the notation T800PEN is used to described
  the softening point

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VISCOSITY

• Viscosity of a fluid is a measure of its
  resistance to tangential or shear stress. It
  arises from interaction and cohesion of fluid
  molecules. All real fluids possess viscosity,
  though to varying degrees. The shear stress in a
  solid is proportional to strain whereas the shear
  stress in a fluid is proportional to the rate of
  shearing strain. It follows that there can be no
  shear stress in a fluid which is at rest (Webber,
  1974).

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VISCOSITY

• As an example, a fluid confined between two
  plates which are situated a very short distance y
  apart. The lower plate is stationary whilst the
  upper plate is moving at velocity v. The layer
  adjacent to the stationary plate is at rest
  whilst the layer adjacent to the moving plate has
  a velocity v. The rate of shearing strain or
  velocity gradient is dv/dy.
• The (dynamic) viscosity, µ, is expressed in mN
  s/m2 or centipoises (ML-1T-1) and given by
• µ Shearing stress/rate of shearing
  strain

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VISCOSITY

• Absolute viscosity is measured by pulling the
  bitumen through the viscometer with a vacuum.
• Kinematic viscosity express the bitumen flow
  under its own weight.
• Viscosity at temperature gt60oC is determined
  using rotational viscometer (Brookfield
  viscometer).
• Viscometer at low temperature (lt 60oC) and wide
  range of loading time can be measured using DSR.

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KINEMATIC VISCOSITY

• Viscosity is also expressed as kinematic
  viscosity, v, in which density is considered in
  the form µ/?. Kinematic viscosity is expressed in
  mm2/s
• (L2T-1) or centistokes where it is
  independent of force.
• The kinematic viscosity of a liquid reduces with
  increasing temperature.
• The kinematic viscosity of water at 15oC is about
  1.14 mm2/s. At room temperature the kinematic
  viscosity of air is about 13 times that of water.

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Brookfield viscometerRotational viscometer
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DSR (Dynamic Shear Rheometer)to measure
viscosity of bitumen
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THE BITUMEN TEST DATA CHART (BTDC)

• BTDC was developed by Heukelom.
• BTDC is a chart to express the relationship
  between penetration and absolute viscosity
  (Poises).
• There are two equi-viscous lines on the chart,
  one occuring at a penetration of 800 representing
  the softening point and another at a penetration
  of 1.25 representing the Fraass breaking point
  (an estimate temperature at which a thin film of
  bitumen might crack).
• Generally bitumen produce data that plot as a
  straight line on the chart.

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TEMPERATURE SUSCEPTIBILITY (TS)

• The consistency of bitumens varies with
  temperature. This depends on the type and grade
  of bitumen.
• Temperature susceptibility (TS) is expressed by
  Penetration Index (PI) that developed by Pfeiffer
  Van Doormaal.
• TS of a bitumen can be seen on the BTDC as a
  straight line with equation
• Log P AT K
• P Penetration A slope of line

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TEMPERATURE SUSCEPTIBILITY (TS)
Log (800) log (P _at_ 25 C)
A
TSP 25 C
Log P
Because value A is too small and this is
inconvenient, so that PI was developed to
indicate the temp susceptibility
Pen
20 (1 25A)
PI
1 50 A
P800
Higher PI means harder bitumen
25 C
TSP
Temperature
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DETERMINING Penetration Index (PI)
Penetration at 25oC (dmm)
Softening Point oC
The arrow indicates the value increases
PI
Softer bitumen
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MECHANICAL PROPERTIES OF BITUMEN

• STIFFNESS OF BITUMEN (Sb)
• Sb Stress/ strain
• Sb can be measured using DSR
• Empirical equation
• Loading time (sec) 1/ Traffic speed (km/hr)

Condition Response Sb
High temperature Viscous Low
Long loading time Viscous Low
Low temperature Elastic High
Short loading time Elastic High
Condition Loading time
Fast speed 0.01 0.10 sec
Parked vehicle 1min-10hours
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EFFECT OF LOADING TIME TEMPERATURE ON BITUMEN
STIFFNESS (Sb)
Elastic asymptote
Sb
Sb
Viscous asymptote
T1 gt
T2 gt
T3
Loading time
Loading time
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DETERMINING bitumen stiffness

1. Measure using DSR (Dynamic Shear Rheometer)
2. Predict using Van der Poel Nomograph
3. Calculate using equation

Using equation Sb 1.157 10-7 t-0.368
2.718-PI (SP-T)5 Only applicable where Loading
time (t) between 0.01 and 0.1
seconds Penetration Index (PI) between -1.0 and
1.0 Temperature difference (SP-T) between 20C
and 60C Sb in MPa SP softening point
Ttemperature
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DETERMINING Bitumen Stiffness (Sb)
Sb
Van der Poel Nomograph The arrow indicates the
value increases
PI
Temperature difference oC
Below T800 pen
Above T800 pen
Loading time (t)
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MODIFIED BITUMEN

• Bitumen can be modified by adding an additive or
  modifier
• in order to improve its mechanical properties,
  for examples
• Obtaining stiffer asphalt mixture at high
  temperature to minimise rutting
• Obtaining softer asphalt mixture at low
  temperature to minimise thermal cracking
• Improving fatigue resistance
• Improving bonding between aggregate and bitumen
  to reduce stripping or moisture susceptibility
• Improving abrasion resistance of mixture to
  reduce ravelling
• Rejuvinating aged bitumen
• Permitting thicker bitumen film to increase the
  mixture durability
• Reducing flushing or bleeding
• Improving resistance to ageing or oxidation

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BITUMEN ADDITIVES OR MODIFIERS

• Filler lime, Portland cement, fly ash
• Rubber natural latex, synthetic latex, reclaimed
  rubber
• Plastic
• Combination rubber and plastic
• Fibre rock wool, asbestos, cellulose
• Hydrocarbon recycling and rejuvinating oils,
  natural asphalt (trinidad lake asphalt, buton
  asphalt)
• Waste materials recycled tyres

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TES OTAK KIRI BACA WARNANYA, BUKAN
WORDNYA KUNING MERAH HIJAU HITAM
BIRU ORANYE COKLAT
JINGGA ABU-ABU
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tugas TULIS TANGAN BUAT PAPER TENTANG ASPAL (5
pages kertas folio bergaris) Latar
belakang Isi Kesimpulan Daftar pustaka