Balancing Paving & Compaction Operations. Presented by Todd Mansell, CAT Paving

Transcription

1 Balancing Paving & Compaction Operations Presented by Todd Mansell, CAT Paving

2 What are we trying to achieve? 1. Tonnage 2. Density 3. Smoothness 4. Efficiency 5. Overall quality

3 How do we achieve these things? 1. Tonnage pave faster more trucks, higher plant output 2. Density add rollers, different types of rollers 3. Smoothness non-stop paving, proper end-dumping 4. Efficiency balance paver speed, roller speed, mix delivery 5. Overall quality paving continuously at manageable pace

4 What is most likely to limit our production? Plant output Trucking/traffic Job layout/mobilization Work hours Other factor(s)?

5 Start with Tonnage How many tons of mix can we place today based on plant capacity or job capacity? Do we have enough trucks to delivery this tonnage from the plant to the job site? Consider traffic patterns Is one paver enough to place? 10-ft paver throughput 1,700 tph 8-ft paver 1,100 tph

6 Lines of Communication Foreman Superintendent Truck Boss Project Manager

7 Balancing Plant, Trucking, Paver, Roller Expected 2,500 tons/day 8-hr paving window End dumping (18-ton) 12-ft wide, unconfined edge 2-inch overlay 12.5mm polymer-modified mix Autumn < 70 F Given 3 rollers 79 steel vibratory (2 x Cat CB54XW) 82 pneumatic (Cat CW34)

8 Planning 20 minutes Pre- paving planning Tons per day Number of trucks needed Paver speed Roller speed Rolling Pattern Density Smoothness Tools available NAPA IS-120 Paving Production Calculator App Amplitude Selection App PaveCool or MultiCool Apps

9 Need 7 pieces of information Use Paving Production Calculator or use NAPA IS- 120 Worksheets 1. Plant tph & silo capacity 2. Paving window 3. Average truck capacity 4. Truck cycle time 5. Mat thickness (loose) 6. Mat width 7. Loose mix density

10 Input 7 pieces of information

11 Number of Trucks = 20

12 Paver speed using end dumps Use 75% efficiency for end-dumping Use 100% for MTV 36 fpm

13 Paver Speed, trucking & plant is balanced

14 Breakdown Intermediate Finish %TMD 90-92% 92-94% 94+ % Temp Coverage F F F (1 vibe, 1 static) Settings High A, Low F 90 psi Low A, static 126 feet 200 feet 200 feet

15 Now, let s look at roller settings & drum width 2 x Cat CB54-XW 79 wide drum 1 x Cat CW34 82 compaction width

16 Vibratory Steel Drum Breakdown, intermediate and finish rolling Settings for amplitude and frequency Static mode for finish rolling Build density from the top down

17 Amplitude = compactive effort High Amplitude Low Amplitude

18 Frequency = speed x impacts per foot Low Frequency High Frequency Roller speed is constant

19 Impacts per foot, Frequency & Roller Speed 10 to 14 Impacts per foot

20 Pneumatic Rollers Most commonly used for intermediate rolling Knead the mix Close up surface voids and tension cracks Efficient building density Build density from the bottom up

21 Tire Pressures Change static force by changing ballast Change static force by changing tire pressure Increase inflation pressure to increase force Decrease inflation pressure to decrease force Higher Pressure Lower Pressure

22 Calculate roller speed steel drum vibratory Roller ground speed (fpm) = Frequency (vpm) Impacts per foot Speed = 3,000 vpm 10 ipf = 300 feet per minute

23 Calculated Effective Roller Speed Effective roller speed = 300 fpm 7 passes = 42 fpm Effective Roller speed = 42 x 0.80 = 34 fpm Paver can not exceed 34 fpm

24 12-Foot Wide Lane: 79 x 2 passes Roller A Roller B 6 Overhang 2 Overlap 6 Overhang 12 Wide Mat

25 12-Foot Wide Lane: 79 x 3 passes Roller A Roller A and/or Roller B Roller B 6 Overhang 6 Overhang 12 Wide Mat

26 Drum width considerations Required Number of Overlapping Passes per Drum Width Paving Width (Meters / Feet) 140 cm (55in) 150 cm (59in) Drum Widths 170 cm (67in) 2.5 / / cm (79in) 3.00 / / / 12 (4) / / / / / / cm (84in) Select optimum drum width to get coverage before the mix cools Maximum 3 overlapping drum widths to cover mat Narrower drums have higher PLI Consider production vs. ability to get density

27 Balancing Plant, Trucking, Paver, Roller Expected 2,500 tons/day 8-hr paving window End dumping (18-ton) 12-ft wide, unconfined edge 2-inch overlay 12.5mm polymer-modified mix Autumn < 70 F Given 3 rollers 79 steel vibratory (2 x Cat CB54XW) 82 pneumatic (Cat CW34)

28 Breakdown Compaction Develops the majority of the density in the asphalt layer Works immediately behind the paver where asphalt is the hottest Must match the production / speed of the paver

29 What is a good target density for breakdown? Job spec is 92-97% Our job target for final density is 94% A good goal for breakdown compaction is 95% of our overall target density 0.95 x 94% 90%

30 Amplitude App

31 Amplitude (recommended by App)

32 Determine Number of Passes Required Experience Test Strip Amplitude Selection App Inputs to App Confirm with Test Strip CB54XW 79 drum Low Amp = High Frequency = 3,800 vpm High Amp = Low Frequency = 2,520 vpm

33 Test Strips Verify equipment and patterns develop required density Plan each phase of compaction Can be done first day of job Sometimes required in advance Don t fake it Communicate plan to all crew members

34 Test Strips Check screed laid density Monitor temperature of the asphalt layer Document start and stop of tender zone, if any

35 Test Strips Check density across width of the asphalt layer Check density after each initial phase pass Outline the gauge placement Write numbers that operator can see

36 Test Strips Pull core as soon as possible Verify accuracy of onsite testing gauge

37 Determine the number of roller passes Set target density values for each roller 95% of target for breakdown roller 100% of target for intermediate roller Remove marks with finish roller sometimes more density Determine number of passes with QC team Start behind screed Breakdown roller, intermediate, finish Take density readings after each roller pass Trial and error to fine tune roller pattern

38 Number of roller passes Breakdown Intermediate Finish 12-ton DDV 14-ton tire 8-ton DDV Settings High A, Low F 1 vibe, low A, high F, 1 static 1 st Pass Temp Density 88% 92% 94% (vibe) 2 nd Pass Temp Density 90% 93% 94% (static) 3 rd Pass Temp Density 91% 93.5% 4 th Pass Temp Density

39 Roller Speed: High Amplitude/Low Frequency Impacts per foot = 10 Drum width = 79 Frequency = 2,520 2 Passes (test strip) 29 fpm 29 fpm < 36 fpm (7-pass pattern)

40 Roller ground speed calculated by hand Roller speed = Frequency (vpm) Impacts per foot Roller Speed = 2,520 vpm 10 ipf = 252 fpm = 2.8 mph

41 Calculated Effective Roller Speed Actual roller speed = 252 fpm 7 passes Actual roller speed = 36 fpm Effective Roller speed = 36 fpm x 0.80 = 29 fpm Paver can not exceed 29 fpm Need 36 fpm from paver to get 2,500 tons per day!!

42 What can I do now!?!? 1. Slow down paver to 29 fpm 2. Set roller at a higher frequency 3. Get an 84 wide roller 4. Get an additional 79 roller

43 Try High Frequency setting 3,800 vpm Lower amplitude MUST verify if we meet 89% with 2 passes 43 fpm 43 fpm > 36 fpm

44 High frequency, but lower amplitude

45 Higher frequency, additional roller pass Higher frequency lower amplitude which requires an additional pass to get same density 34 fpm 34 fpm < 36 fpm

46 What can I do now!?!? 1. Slow down paver to 29 fpm 2. Set roller at a higher frequency 3. Get an 84 wide roller 4. Get an additional 79 roller

47 Roller selection do we have a choice? Mix of roller types Drum width, weight, amplitude, frequency Number of rollers

48 12-Foot Wide Lane: 84 x 2 passes Roller A Roller B 6 Overhang 12 Overlap 6 Overhang 12 Wide Mat

49 Amplitude for 84 drum machine

50 Roller speed using 84 drum Wider drum Lower frequency Higher amplitude Passes (test strip) 42 fpm 42 fpm > 36 fpm

51 Could have selected a 67 in 3 passes Roller A Roller A and/or Roller B Roller B 13 Overlap 13 Overlap 6 Overhang 6 Overhang 12 Wide Mat

52 Establish an effective rolling pattern 1. Based production and density 2. Equipment Selection 3. Balance paver & roller speed 4. Test Strip Decision Point Decision Point 5. Verify during production

53 How far back?? Breakdown

54 What does it take to get density? Temperature Temperature Temperature

55 Time Available for Compaction Density must be achieved while the mix is still HOT

56 Temperature is Critical Breakdown rolling Intermediate rolling possible tender zone Finish rolling 160 Stop rolling Keep steel drums off the mix!!!

57 MultiCool Website and Android App Google Play App store 57

58 Length of the Roller Pass Speed = Distance Time Roller speed based on frequency (ipf) Time available for compaction (MultiCool) Solve the equation for distance

59 Length of the Roller Pass Distance = Speed x Time

60 Roller Ground Speed Distance = Speed x Time Speed Calculation Frequency = 2,640 vpm We want 10 impacts per foot 2, = 264 fpm

61 MultiCool from 275 F to 252 F (breakdown roller only) Time 3 minutes

62 Length of the Roller Pass Roller speed = 264 fpm Time = 3 minutes Distance = Speed x Time = 264 x 3 = 792 ft (in 3 minutes)

63 Length of the Roller Pass We lose some distance changing direction Assume 80% roller efficiency 792 x 0.80 = 633 feet traveled in 3 minutes We have a 5-pass pattern (from test strip) to cover the mat twice = 126 feet Length of roller pass = 126 feet **If conditions change re-calculate the length of roller pass

64 Put it all together! 1.Types of rollers 2.Amplitude & Frequency steel drum 3.Pneumatic tire roller settings 4.Time Available for Compaction 5.Number of roller passes

65 Sequence & Timing Breakdown Intermediate Finish %TMD 90-92% 92-94% 94+ % Temp Coverage F F F (1 vibe, 1 static) Settings High A, Low F 90 psi Low A, static 126 feet 200 feet 200 feet

66 What if I m just static rolling no vibe? Breakdown good walking pace About 4 mph (350 fpm) Too fast will tear the mat

67 What if I have an MTV? Use 100% efficiency on Paver Speed Technology now to keep distance between MTV and paver

68 Who s responsibility is it? Paver Speed? Roller operator? Roller Speed? Roller operator? Quality Control? Foreman Superintendent Truck Boss Project Manager Quality Control Meeting Density & Smoothness targets? Quality Control?

69

70 Thank-you for your attention! Questions? 2017 Caterpillar All Rights Reserved Materials and specifications are subject to change without notice. Featured machines in photography may include additional equipment for special applications. CAT, CATERPILLAR, BUILT FOR IT, their respective logos, Caterpillar Yellow, and the POWER EDGE trade dress, as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission.