HMA Construction Program Module 5 – HMA Placement.

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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

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

Too Low

Rocks are DraggedFines Accumulate

Lead Crown

Tail Crown

Correct RelationshipMaintained by Chain

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

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%

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

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%

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