Hot Mix Asphalt Production

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Hot Mix Asphalt Production
Road Pavement Forum 10th April 2006

• Chris Lange PMP, Pr.Tech.(Eng)
• Director (Technical)
• Much Asphalt (Pty) Ltd

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Hot Mix Asphalt Production

• Plant types and basic components
• Plant calibration
• Dust extraction
• Filler handling and control
• Aggregate heating
• Procurement / handling of raw materials
• Finished product storage
• Delivery

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Drum Mix Plant - Conventional
Hot Storage Bins
Filter Baghouse
Exhaust Fan
Primary dust collector
HMA made continuously and sent to storage silos
Bitumen Tanks
Drying and mixing drum
Belt scale
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TWIN DRUM PLANT COUNTER-FLOW
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Old Drum Mix Mix Plant
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Twin Drum Plant
Plant filler storage and feed
RAP Feed
Filter Baghouse
Coating mixing drum
Aggregate feed
Finished product storage
Drying heating Drum
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Parallel-Flow Drum-mixer Zones
Combustion
Air
Heating
Drying
Mixing
BIT.
Hot Mix Asphalt
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Counter-Flow Drum-mixer Zones
Aggregate
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Counter-Flow Batch Plant Dryer Zones
Combustion
Heating
Drying
Air
Aggregate
Hot Aggregate
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Batch Plant Elements
Bitumen storage tanks
RAP Feed
Dryer Drum
Cold feed bins
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Screens size aggregate
Hot aggregate travels up bucket elevator
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Aggregate Hot Bins
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Warren Brothers Patent Application Drawing
Original Batch Plant
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Belt Scale Calibration
Cold feed system
Belt scale
Reference scale
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Cold Feed Bins and RAP Bin
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Graphing the Feeders
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Tachometer Mounted on Tail Pulley of Cold Feed
Bin Belt
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No Flow Paddle at Feeder Discharge
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Induced Air Burner
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Fuel Reticulation and Heating System
HFO Tank
In-line heater
HFO Sampling pt
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Drum Flights / Lifters
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Primary and Secondary Emission Control
Primary Dust Collector
Filtered Air
Secondary Dust Collector
Fines collected and returned
Drying Drum
Exhaust Fan
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Primary CollectorCyclone
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Multi-Tube Collector
Outlet tube
Gas inlet
Spin vanes
Inlet tube
Collector element
Valve
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Discharge Housing Functions as a Knockout Box
Air
Gas flow
Optional knock down plate
Bitumen
Fines mix with hot mix asphalt
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Cutaway Section of a Typical Baghouse
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Pulse Jet Baghouse
Exhaust fan
Exhaust fan
Manifold
Manifold
Dust screw
Dust screw
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Automatic Damper Controls
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Cyclone, Screw Collector, and Hot Elevator
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Filler Weigh-Pod After Surge Silo
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Emission Control Summary

• Remove particulate matter
• Primary
• Secondary
• Return fines to the mix
• Affects void content
• Affects mix stiffness
• Difficult to control

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Batch plant filtration
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Aggregate storage
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Aggregate Storage
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Bitumen Storage
BITUMEN TANKS ELECTRICALLY HEATED/ 24 HR
TEMPERATURE MONITOR AND CONTROL
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Old Style Operating Cabin
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Plant automation Modern control cabin
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Plant automation
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Roodepoort Op Screen
Plant Automation Operating System Graphics
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Batch Plant Schematic
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Batch Plant Op Screen
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Laboratory from the past
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Modern Asphalt Laboratory
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Quality Control Trends Monitored
Binder Content
Voids in Mix
Filler Content
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Slat Conveyor Feeding Storage Silos
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Hot Storage Skip and Winch System
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Storage Silo 165 t Capacity
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Correct Loading Sequence
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The good old days
The End