HMA PLACEMENT. NCAT 2 To Be Covered Hauling Placement Compaction.
Post on 29-Jan-2016
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HMA PLACEMENT
NCAT 2
To Be Covered
• Hauling
• Placement
• Compaction
NCAT 3
Tandem Axle End Dump Truck
NCAT 4
High Dump Semi-truck
NCAT 5
Belly Dump
NCAT 6
Multi-WHEELEDConveyor Feed
NCAT 7
Self Propelled Paver
NCAT 8
Self Propelled Paving Machine
THE BASIC PRINCIPLE HAS NOT CHANGED
MUCH
NCAT 9
Self Propelled Paving Machine
HMA Flow
NCAT 10
Screed Unit
NCAT 11
Forces On Screed
NCAT 12
ONE OF THE ONE OF THE ESSENTIALS ESSENTIALS
FOR A FOR A CONSISTENT CONSISTENT
AND HIGH AND HIGH QUALITY HOT QUALITY HOT MIX ASPHALT MIX ASPHALT
PAVEMENT IS TO PAVEMENT IS TO PROVIDE FOR A PROVIDE FOR A
CONTINUOUS CONTINUOUS OPERATIONOPERATION
NCAT 13
NCAT 14
Material Transfer Device
NCAT 15
COMPACTION
GOOD COMPACTION
LEADS TO GOOD PERFORMANCE
NCAT 16
Reason For CompactionReason For Compaction
• To prevent further compactionTo prevent further compaction
• To provide shear strength or resistance To provide shear strength or resistance
to ruttingto rutting
• To ensure the mixture is waterproofTo ensure the mixture is waterproof
• To prevent excessive oxidation of the To prevent excessive oxidation of the
asphalt binderasphalt binder
NCAT 17
Durability vs Air Voids
% Air Voids
StabilityCohesion
Zone of Highest
Durability
0
Flushing Raveling
NCAT 18
Factors Affecting CompactionFactors Affecting Compaction
• Mix PropertiesMix Properties– AggregateAggregate– Asphalt Asphalt – Mix TemperatureMix Temperature
• Layer ThicknessLayer Thickness
• Environmental FactorsEnvironmental Factors
• RollersRollers
NCAT 19
Temperature is critical
NCAT 20
RollersRollers• VibratoryVibratory
• Pneumatic-tiredPneumatic-tired
• Steel wheeled tandem rollersSteel wheeled tandem rollers
NCAT 21
Vibratory Roller
NCAT 22
Pnuematic Roller
NCAT 23
Steel Wheeled Roller
NCAT 24
Checking Density With Nuclear Gauge
NCAT 25
Extracting A Core
NCAT 26
Questions - ?
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