HMA PLACEMENT. NCAT 2 To Be Covered Hauling Placement Compaction

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 - ?