Matakuliah
Tahun
: S0753 – Teknik Jalan Raya
: 2009
Pavement Material
Session 07-08
Contents
•Pavement Classification ( material )
•Pavement
•Base course
•Pavement material and Testing laboratory
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Asphalt
• Asphalt is bitumen.
• Bitumen is the organic binder, composed of HC with
low melting point thermoplastic polymers and oils.
• Asphalt mix is composite of aggregate and bitumen.
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Asphalt Mix
• The aggregate use as in the concrete that should be
clean and angular.
• Aggregate should have distribution of grain sizes to
provide a high packing factor and good mechanical
interlock between aggregate grains.
A
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Composite and binder
• Binder is just enough for the aggregate particle to
touch, but voids are minimized.
• Excess binder is weakening asphalt under load due
to viscous deformation.
• When asphalt mix is compress, the binder can
squeeze into voids.
• Too much void space permit water to enter the
structure; increase the rate of deterioration of
asphalt and may also embrittle the binder
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Operation of Asphalt Mix
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Operation of Asphalt Mix
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Asphalt Mix Problem
• Asphalt (bitumen) in asphalt mix soften at relative low
temperature because it is a thermoplastic polymer.
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Base Course
•Sand
•Aggregate
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Sand
•
•
•
•
•
•
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Chemically sand = silica (SiO2)
Fine minerals
The order of 0.1 to 1.0 mm diameter
Contain at least some absorbed water
Fill voids between the coarser aggregate
Giving high packing factor
Reducing amount of open (or interconnected) porosity in the
finished concrete
• Reducing disintegration of the concrete due to repeated
freezing and thawing during service
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Aggregate
• Gravel & Rock
• Aggregate must be clean, strong, and durable
• Angular aggregate particles provide strength
due to mechanical interlocking between
particles
• More surface on angular particles may form
voids or cracks
• The large size of aggregate is preferred
• Aggregate particles should not be larger than
about 20% of the thickness of the structure or12
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Pavement Material & Testing Laboratory
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Pavement Material & Testing Laboratory
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Pavement Material & Testing Laboratory
The basic concepts of the Marshall mix
design method were originally developed
Bruce Marshall
by
of the
Mississippi Highway Department around
1939 and then refined by the U.S.
Army. Currently, the Marshall method is
used in some capacity by about 38 states.
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Pavement Material & Testing Laboratory
Currently, the Marshall method is used in
some capacity by about 38 states. The
select the
asphalt binder content at a
Marshall method seeks to
desired density that satisfies minimum
stability and range of flow values (White,
1985).
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Pavement Material & Testing Laboratory
This appended test was eventually recommended for
adoption by the U.S. Army because:
•It was designed to
than just a portion of it.
stress the entire sample rather
•It facilitated rapid
testing with minimal effort.
•It was compact, light and portable.
•It produced densities reasonably close to field
densities.
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Pavement Material & Testing Laboratory
The Marshall mix design method consists of 6
basic steps:
•
•
•
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•
Aggregate selection.
Asphalt binder selection.
Sample preparation (including compaction).
Stability determination using the Marshall stability
and flow test.
Density and voids calculations.
Optimum asphalt binder content selection.
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Pavement Material & Testing Laboratory
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