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HMA Construction ProgramHMA Construction Program
Module 5 – HMA PlacementModule 5 – HMA Placement
Module 5 – Objectives Module 5 – Objectives
• Objective of HMA PlacementObjective of HMA Placement
• Components and Function – Tractor and Components and Function – Tractor and Screed Unit Screed Unit
• Operational Principles of Screed Operational Principles of Screed
• Grade and Slope Control Systems Grade and Slope Control Systems – TypesTypes– FunctionsFunctions– CapabilitiesCapabilities
Module 5 - Objectives (cont.) Module 5 - Objectives (cont.)
• Yield-Thickness-Smoothness Yield-Thickness-Smoothness RelationshipRelationship
• Types of Paving and When to Use ThemTypes of Paving and When to Use Them
• Night PavingNight Paving
• Paver MaintenancePaver Maintenance
• Operating TechniquesOperating Techniques
Push Rollers
Tractor
Hopper
Tow Point
Side ArmConveyors
Screed
Depth Crank
Augers
Tractor Unit Tractor Unit
• Drive Systems Drive Systems
• Push Rollers and Truck Hitches Push Rollers and Truck Hitches
• Hopper Hopper
• Slat ConveyerSlat Conveyer
Tractor Unit (Cont'd)Tractor Unit (Cont'd)
• Conveyer Flow Gates Conveyer Flow Gates
• AugersAugers
• Materials Feed SystemMaterials Feed System
• Tow Points Tow Points
• MaintenanceMaintenance
Hopper Wings
Slat ConveyorsHopper Gates Augers
Screed Plate
ProportionalFeed Control
Material Flow
Support MountSupport Mount
OffOffOnOn
Control ArmControl Arm
Extendable WandExtendable Wand
StopStopLimit SwitchLimit Switch
Control Arm ClampControl Arm Clamp
Material Retaining Plate
Auger
Active Material
Target in the Target in the Center AreaCenter Area
Active MaterialActive Material
AugerAuger
Tow PointTow Point
Paver MaintenancePaver Maintenance
• Washing downWashing down
• Wear check Wear check
• Storage of electrical equipment Storage of electrical equipment
• ChecklistsChecklists
FORM 5-1 PAVER MAINTENANCE CHECKLIST Page 1 of 2
Paver ID#:_________________________________Date:____________________________
CHECK DAILY
(1) COOLING SYSTEM - (a) Check coolant level; (b) Check radiator core for plugging with dirt or oil; (c) Check hoses for cracking andleaking; (d) Check belts for proper tension; (e) Check fan for loosebearings. Fill, adjust and/or replace as needed.
(2) ENGINE LUBE SYSTEM - (a) Check engine oil level; (b) Check for any leakage on or around engine; (c) Report any discolorations(milky) or overfilled conditions right away.
(3) FUEL SYSTEM - (a) Check sediment bowl for dirt or water and clean as needed; (b) Check for any leaks around lines and fittings.DO NOT OVERTIGHTEN.
(4) HYDRAULIC SYSTEM - (a) Check oil level; (b) Check and look for any leaks around pumps, lines, fittings, and filters. DO NOTOVERTIGHTEN.
(5) ELECTRICAL SYSTEM - (a) Look at the wiring and connections for being loose or oily. If oily, spray with contact cleaner. (b) Look atbattery cable connections and clean if starting to corrode.
(6) TIRES - (a) Check tires and maintain ___ lb. air pressure. Note: Tires are also 75% to 100%, filled with calcium chloride solution.
(7) INSPECTION - (a) Look for loose bolts and tighten right away when found; (b) clean out hoppers, augers and screed after eachdays run and spray with cleaner; (c) Keep top deck and screedclean; (d) Check wheel drive chains, conveyor drive chains andconveyor flight chains for being too loose. Adjust as needed. Don'trun machine with loose chains; (e) Check for other oil or greaseleaks from gear boxes, transmission, differential, axle hubs andreport to shop immediately.
CHECK WEEKLY
(1) BRAKE SYSTEM - (a) Check both LH and RH master cylinders for hydraulic brake fluid level. Keep filled to proper level.
DAILY LUBRICATION
(1) Vibrator shaft bearings and U-Joints on vibrator shafts. DO NOT FLUSHGREASE.
(2) Auger shafts flange bearings. (twice daily) (3) Rear conveyor flight shaft bearings. (4) Front conveyor flight shaft bearings. SEE OPERATORS MANUAL (5) Jack shafts and idler sprockets. (6) Screed arm lower pivot pin.
WEEKLY LUBRICATION
(1) Screed Crank (2) Clutch Throwout Bearing (3) Clutch Lever Shaft (4) Brake Pedals (5) Bogie Pivots and King Pin Bearings. SEE OPERATORS MANUAL (6) Bogie Wheel Bearings (7) Drive Wheel Bearings (8) Main Drive Shaft
OILS & GREASES & FILTER CHANGES
(1) ENGINE - Change oil and filter every 150 hrs. For oil, see engine manual. (2) HYDRAULIC SYSTEM - Change oil yearly, and change filter 3 times a season. (3) AIR CLEANER - Oil both every 150 hrs. Dry the cleaners 3 times a year. (4) FUEL SYSTEM - Filter change 3 times a year. (5) PUMP DRIVE BOX, TRANSMISSION, DIFFERENTIAL, LH & RH CONVEYOR
DRIVE BOXES - Change gear lube yearly; use 85W140 gear oil.
(1) Drive chain: Adjust 19 mm slack one side (2) Conveyor Drive Chains. Larger units: 125-175mm from ground. Smaller units:
75-125mm from frame.
OTHER THINGS THAT NEED SPECIAL ATTENTION AND HANDLING
(1) Grade and Slope Boxes and Cables (2) Screed Extensions (3) Skis (4) Don't tamper with the governors or speed adjusting screws.
(Courtesy of Blaw-Knox)
REMARKS:__________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Completed by:____________________________________________
Screed Unit Screed Unit
• Screed plateScreed plate
• Strike-offStrike-off
• Crown controlCrown control
• Extensions and end plates Extensions and end plates
Screed Unit (continued)Screed Unit (continued)
• Thickness Control ScrewsThickness Control Screws
• Screed ArmScreed Arm
• Pre-Compaction SystemPre-Compaction System
• Heating Systems Heating Systems
• Maintenance Maintenance
Strike-off
Correct
Strike-off Wear
Too High
Strike-off
Wear
Too Low
Rocks are DraggedFines Accumulate
Lead Crown
Tail Crown
Correct RelationshipMaintained by Chain
A
B
C
A - Lead crown too high Heavy mat’l flow in centerB - Lead crown too low Heavy mat’l flow at edgesC - Uniform mat texture and material flow from correct crown adjustment
INCREASE
DECREASE
Hand cranks Hand cranks turned clockwise turned clockwise
to thickento thicken
Tow point Tow point unchangedunchanged
Tow point raisedTow point raisedHand cranks Hand cranks unchangedunchanged
Vibratory Shaft With Weights
Pull PointToo High
AbnormalWear
AbnormalWear
Pull PointToo Low
Pull PointCorrectHead of Material
Level with Auger ShaftNormalUniform Wear
Slight Positive Angle of Attack
Operational Principles of the Operational Principles of the ScreedScreed
• Self-leveling Concepts Self-leveling Concepts
• Screed Response versus Distance Screed Response versus Distance
• Forces Acting on a ScreedForces Acting on a Screed
Self Leveling - Rubber Tired Paver
Rear Drive TiresFront Bogie Wheels
Line of Pull
Detail of Screed PathDetail of Screed Path
Tow Point PathTow Point PathStep Amplitude = 100%Step Amplitude = 100%
L = Leveling Arm LengthL = Leveling Arm Length
Screed PathScreed PathDirection of PavingDirection of Paving
63%63% 87%87%
6L6L5L5L4L4L3L3L2L2L1L1L00
96%96% 98%98% 99%99%
L
25mm movement at Tow Point
3mm movement at Leading Edge of Screed
Main Forces Acting on Screed Main Forces Acting on Screed
1. Speed of Paver1. Speed of Paver
2. Head of Material 2. Head of Material
3. Angle of Attack 3. Angle of Attack
4. Other Forces 4. Other Forces – Pre-compaction Pre-compaction – Screed WeightScreed Weight
Tow Point
Screed DepthCrank
Pivot Point
F1
F2
F3
SuperpaveSuperpave
• Coarser mixturesCoarser mixtures
• Modified asphaltModified asphalt
• Effect on Paving?Effect on Paving?
Constant Head of Material Volume
Head of Material Volume Too High
Head of Material Volume Too Low
Correct Depth ofMat Maintained
Screed Rises Due toExcess Material ForcedUnder Nose of Screed
Screed Settles Due toInadequate Supporting
Material
Correct Correct ElevationElevation
Auger Auger OverloadedOverloaded Auger Auger
UnderloadedUnderloaded
Travel
Angle of Attack
Screed Control SystemsScreed Control Systems
• Who’s Responsible for Changes Who’s Responsible for Changes
• Sticking the Mat Sticking the Mat
• Manual Controls Manual Controls
• Automatic Controls Automatic Controls
Pavement ProfilePavement Profile
Direction of PavingDirection of Paving
Detail of Screed PathDetail of Screed Path
Tow Point PathTow Point PathStep Amplitude = 100%Step Amplitude = 100%
L = Leveling Arm LengthL = Leveling Arm Length
Screed PathScreed PathDirection of PavingDirection of Paving
63%63% 87%87%
6L6L5L5L4L4L3L3L2L2L1L1L00
96%96% 98%98% 99%99%
L
Types of Grade Reference Types of Grade Reference
• Stringline Stringline
• Mobile referenceMobile reference
• Joint matching shoe Joint matching shoe
• Sonic sensorSonic sensor
• LaserLaser
Grade Sensor - Side Arm MountGrade Sensor - Side Arm Mount
Grade Sensor - Screed End MountGrade Sensor - Screed End Mount
Yield-Thickness-SmoothnessYield-Thickness-Smoothness
• Base Condition Base Condition
• Minimum Thickness Minimum Thickness
• Yield Yield
• SmoothnessSmoothness
• Controlling Yield versus Thickness or Controlling Yield versus Thickness or Smoothness Smoothness
Types of Paving Types of Paving
• Planning Pulls Planning Pulls
• Mainline Paving Mainline Paving
• Variable Width Paving Variable Width Paving
• Transitions Transitions
• Temporary Paving Temporary Paving
• Echelon Paving Echelon Paving
• Night Paving Night Paving
Operating Techniques Operating Techniques
• Determining Paver Speed Determining Paver Speed
• Warming up Machine Warming up Machine
• Positioning on Joint Positioning on Joint
• Nulling the Screed Nulling the Screed
• Initial Settings Initial Settings
• Charging Hopper, Tunnels, ScreedCharging Hopper, Tunnels, Screed
Operating Techniques (Cont'd)Operating Techniques (Cont'd)
• Pulling off Joint Pulling off Joint
• Re-checking Settings Re-checking Settings
• Speed of Paver Speed of Paver
• Checking YieldChecking Yield
• Truck Exchanges Truck Exchanges
• Folding Hopper Wings Folding Hopper Wings
Operating Techniques (Cont'd)Operating Techniques (Cont'd)
• HMA Level in Hopper HMA Level in Hopper
• Auger Operation Auger Operation
• Flow Gate Position Flow Gate Position
• Raking and Luting Raking and Luting
• Traffic Control Traffic Control
• Concluding Paving Concluding Paving
Balancing ProductionBalancing Production
TruckingTrucking CompactionCompaction
PavingPavingHMA HMA FacilityFacility
PAVING PRODUCTION CALCULATION FORM:
Date:_____________________ Project #: _______________
Project:________________________________________________
Tonnes scheduled to be placed today (T-MIX): __________ tonnes
Hours of Paving Scheduled (P-TIME): _________hours
Mix Delivery Rate (H-RATE):= T-MIX P-TIME= _______ _______ = _______ tph
Paving Width (WIDTH): _______ m
Paving Thickness (THICK): ______ millimeters
Compacted Mix Density (DENSITY):
Specification limits for density: Minimum = ______; Maximum = ______The in-place target density should be above the Minimum: Target = ______
DENSITY = Reference Density x % Target Density= _______ kg/cu m x _______= _______ kg/cu m
Actual Paver Production Rate (P-RATE):
= MIX RATE (tph) x 1,000 kg x _1 hr__ WIDTH (m) THICK(m) DENSITY(kg/m 1 tonne 60 min
= x 1,000 60
P-RATE = ______ meters/min
Paving Efficiency Factor (EFF1): ______ (recommended: 0.75 - 0.85)
Actual Paver Speed (PAVER):
PAVER = P-RATE EFF1 = _______ _______ = _______ meters/min
Starting BlocksStarting Blocks
A good rule of thumb is to raise the screed 20 A good rule of thumb is to raise the screed 20 percent more than the compacted thickness.percent more than the compacted thickness.
1/41/4
Hydraulic Strike-OffHydraulic Strike-OffWith Vertical BladeWith Vertical Blade
Lead Crown - Lead Crown - 3 mm Greater 3 mm Greater
Than Tail CrownThan Tail Crown
Gates too HIGH - augers overloadedGates too HIGH - augers overloaded
Gates too LOW - insufficient material supplyGates too LOW - insufficient material supply
Correct adjustment - uniform material volume/flowCorrect adjustment - uniform material volume/flow
Re-Checking Settings Re-Checking Settings
• Is thickness okay?Is thickness okay?
• Is cross slope okay?Is cross slope okay?
• Is mat texture okay?Is mat texture okay?
Check Check Yield Yield
OccasionallyOccasionally
Module 5 – Objectives Review Module 5 – Objectives Review
• Objective of HMA PlacementObjective of HMA Placement
• Components and Function–Tractor and Components and Function–Tractor and Screed Unit Screed Unit
• Operational Principles of Screed Operational Principles of Screed
• Grade and Slope Control Systems Grade and Slope Control Systems – TypesTypes– FunctionsFunctions– CapabilitiesCapabilities
Module 5 – Objectives (cont.) Module 5 – Objectives (cont.)
• Yield-Thickness-Smoothness Yield-Thickness-Smoothness RelationshipRelationship
• Types of Paving and When to Use ThemTypes of Paving and When to Use Them
• Night PavingNight Paving
• Paver MaintenancePaver Maintenance
• Operating TechniquesOperating Techniques