End of Load Segregation identification, causes, cures Part 2

Transcription

1 End of Load Segregation identification, causes, cures Part 2

2 Definition End-of-Load segregation is a recurring pattern of segregation created during paving operations. Typically, it is the result from improper Truck/Paver interaction and exaggerated by improper individual operation of the truck and paver.

3 EOL Segregation A recurring pattern

4 Side-by-Side

5 Side by side

6 Side by side, recurring

7 Open Texture, Water slow to go.

8 Open Texture

9 Open Texture on Dense Graded Mix

10 Side by side, recurring

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12 What End of Load Segregation isn t? Random roughness, localized segregation or surface texture issues due to paver, screed or handwork.

13 Screed texture: Not EOL Segregation

14 Not EOL Segregation

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16 Texture due to handwork

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18 Performance Issues? End of Load segregation is typically is seen as a coarser location(s) in the asphalt mat and will have higher air voids making the asphalt more susceptible to early distress due to oxidation, moisture penetration, resulting in raveling and pot holes.

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20 Performance Issues Affects smoothness/ride/iri (a typical dip/low in these areas) Increases dynamic load on pavement Accelerates damage to pavement Potential VAAP Issues Moisture damage Raveling

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22 Areas to look at. Mix Stuff Plant Stuff Road Stuff

23 Mix Stuff Smooth gradation bands minimize segregation prone mixes. Gap Graded mixes more prone to. Look at your mix production data is this mix difficult to control? Big swings in #4/#8, AC, and Air Voids?

24 Plant Stuff

25 Plant Stuff Stockpile aggregate control know what s in your piles. Truck Load out load in multiple drops ensuring mix against front and back of truck bed. Silo don t load below the top of the silo cone increases probability of creating segregation. Don t top off the load by dribbling no bones, baby!

26 Know your stockpiles.

27 Silo Load out

28 Road Stuff (Part 1) What won t cause end of load segregation? Milling, sweeping, tacking, rolling What will cause end of load segregation? Improper Trucking, Paving, and/or MTV operation. Lack of attention to detail i.e. sloppy paving

29 Minimum QC Requirements Additional language added to Section 330 in the July 2011 workbook. 4. Pavement Texture: Monitor the pavement texture to minimize pavement segregation. Use density gauges, infrared temperature measurement devices, or roadway cores at the beginning of each day s production, and as necessary, both at truck exchanges and during normal paving operations.

30 Trucking: no flying in formation, keep your interval. Don t dawdle after finishing the drop. Make sure trucker know what there anticipated cycle time should be. Trust, but verify

31 Truck loaded properly to avoid free space in front and back (mix in mass)

32 Reduce the Break & Run Distance The Greater the Chance for Segregation! - The Larger the Nominal Size of Aggregate - The Steeper the Angle of Repose - The More Distance the Material is Allowed to Move

33 Road Stuff (Part Deux) Balance your paving operations. Establish a constant paver speed based on available production and stick to it. Don t speed up to empty out trucks. Keep the Mix in a mass! Bump wings, don t fold completely or bang. Don t drop level below ¼ or empty hopper or insert between loads.

34 Paver Hopper Is the mix in a mass?

35 Are the slats covered at all times?

36 Keeping mix in a mass in the hopper.

37 Want to fix most EOL Segregation? Keep Mix in the Hopper! Keep your Slats covered!

38 Making it disappear. Communication at Key Times: Initial production on project. Review paving ops, truck exchanges, MTV operation When changes in crews, equipment, long breaks between paving. Proper trucking, loading, paving ops Keep the mix in a mass. Don t empty hopper between loads! Will a MTV cure End of Load Segregation? It will, if operated properly, but at a cost. Can I do it without a MTV? Yes Either way, every ton every day The same way.

39 Uniform That s nice!

40 Smooth and Uniform!

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42 End of Load Segregation Is important to address. Is a Specification issue Is high on the radar. Look for the signs. Is preventable. Keep making Asphalt, the Smooth Ride!

43 You Too Can Do This!