NEW TECHNOLOGY & APPROACHES TO ADDRESS PAVEMENT CONSTRUCTION ISSUES

Transcription

1 NEW TECHNOLOGY & APPROACHES TO ADDRESS PAVEMENT CONSTRUCTION ISSUES NORTHEAST ASPHALT USER/PRODUCER GROUP OCTOBER 12,2006 CHUCK DEAHL BOMAG AMERICAS, INC.

2 Pavement Construction Issues No Compaction In Embankment & Base Segregation Poor Rolling Procedures

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6 Roller mounted compaction measurement and documentation systems

7 Interpretation of Omega values

8 Development of Omega values during compaction

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12 GPS POSITIONONG Two GPS Antenna Reference station ( Trimble ) High accuracy ( 5cm ) RTK ( real time ) BCM 05 positioning software

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17 Causes of Segregation Physical segregation of coarse and fine materials Mat temperature differentials immediately behind the paver Localized cooling of the mix in haul trucks and formation of crust

18 Key Points in Prevention of Segregation: Prevent Dribbling of Materials Keep Material Contained Move Material in a Smooth Uniform Uninterrupted Manner.

19 Segregation Prior to Placement: Material Production HMA Plant

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24 Segregation During Placement Material feed system Flow Gates Slat Conveyors Hopper Augers Sensors

25 Cause: Material Segregated in Truck Running Conveyor Deck Dry Cycling Hopper Wings Too Soon

26 Nonstop Paving Use of loading or transfer machine Goals: To stabilize a paving operation so the paver can maintain a constant unchanging paving speed, eliminating the stops and starts traditionally associated with trucks dumping directly into the paver.

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29 A new tool for identifying Segregation

30 *>232.9 F Segregation Free area *<103.1 F

31 What Your eyes see

32 *>229.8 F What the camera sees Type B Mix *<86.8 F

33 *>281.8 F Stopping the Paver Screed Mark *<113.7 F

34 *>288.0 F *<110.2 F Spot Spot Stopping The paver, Cooler Mix Superpave Mix

35 BASIC PRINCIPLES OF GOOD COMPACTION KNOW THE VARIABLES KNOW THE SPECS ESTABLISH A PATTERN TO ACHIEVE: COVERAGE, DENSITY, SMOOTHNESS, AND BALANCED PRODUCTION KNOW THE BASIC OPERATION OF EACH TYPE OF ROLLER

36 COMMUNICATION COMPACTION GOALS DENSITY SMOOTHNESS BALANCED PRODUCTION

37 FACTORS AFFECTING COMPACTION MIX DESIGN AGGREGATE AND ASPHALT CEMENT LAB DENSITY & FIELD DENSITY CLIMATIC CONDITIONS PAVER TYPE AND PAVING METHOD TEMPERATURE: MAT, BASE AMBIENT, DIRECTION OF SUN; WIND

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54 Lift Thickness Recommended 3:1 to 6:1 Thickness:NMAS Thin lifts cool faster less time available for compaction

55 Effect of Lift Thickness on Density 14.0 Summary of Lift Thickness Experiment 12.0 Air Void Content, % t/nmas Ratio

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66 TRAVEL SPEED OF ROLLERS DOUBLE DRUM VIBRATORY 2-4 MPH PNEUMATIC ROLLER 2-3 MPH STATIC STEEL WHEEL ROLLER 3-5 MPH SPEED CAN KILL

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69 INTELLIGENT COMPACTION A SYSTEM FOR MEASURING THE STIFFNESS OF HMA ON THE ROLLER A RECORDING OF THAT STIFFNESS MEASURMENT PROOF OF THE STIFFNESS OF THE HMA AS RELATED TO DENSITY PROVIDING INFORMATION FOR THE ROLLER TO MAKE DECISIONS

70 VARIOMATIC roller with directed vibration Control unit

71 Asphalt Manager with new measuring value E VIB [MN/m²] and temperature gauge

72 The Operator Asphalt Manager: Easy to understand

73 Bomag Operational Panel 0 fixed variable 0,2 mm 0-0,2 mm 0,4 0,6 0-0,6 0,7 0,93 0-0,93 6 x 3 x Manual - Auto Compaction Modes 0,08 in 0,24 in 0,37 in

74 Bomag Operational Panel PRINTER -Start -Stop - Print out - Delete Test procedere: - Mark the track to be compacted - Manual operation mode with - Fixed amplitude - Fixed working speed

75 Printer

76 E VIB - Printer E VIB Max. / E VIB Min. E VIB Average Frequency Average Speed Track length Temperature

77 E VIB and Density as function of passes; BW 174 AD Asphalt Manager, Automatic mode; Asphalt Base 0/32 CS B65, Nürnberg A3 E VIB [MN/m²], [ C] Evib Surface temp. Core temp. Troxler density [%] 4 cm SMA 0/11 S 8 cm Binder 0/22 > 10 cm ATS 0/ Passes

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81 Benefits for Contractors: Asphalt Manager Investment for Profit Compaction - Uniform and predictable results whilst rolling - Avoids under / overcompaction - Better eveness and roughness - Eliminates drum bouncing Economical and quality aspects - More efficient roller utilisation with fewer passes - Reduced shock loads in sensitive environment e.g. buildings, bridges - Area coverage method

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85 $ VALUE I/C MEASURES THE STIFFNESS OF A LIFT OF HMA DENSOMETERS MEASURE DENSITY OF HMA THIS GIVES US TWO MEASUREMENTS OF THE STABILITY OF THE HMA WHY CUT SO MANY CORES THAT COST $ $ A CORE

86 THE END QUESTIONS??