Louisiana s Experience

Transcription

1 ALF Crumb Rubber Modified Asphalt Louisiana s Experience Louisiana Transportation Conference Baton Rouge Louisiana February 9 th, 2009 Chris Abadie

2 Summary of Louisiana ss Experience Eight CRM asphalt pavement sections using eight different CRM processes Conventional sections constructed as controls Laboratory and field performance testing and observations to evaluate performance ALF test sections 2008 Interstate Projects

3 Locations

4 CRM Descriptions Location Project No. Description 1 OGFC (17.5% Arizona Wet) w/ AR Modified SAMI US CRM (17.5% Arizona Wet) Gap Graded Polymer Modified Gap Graded Wearing Conventional Dense Graded CRM (3% PlusRide Dry) Gap Graded LA 1040 CRM (3% PlusRide Dry) Gap Graded Conventional Dense Graded US CRM (5% Neste Wright, Wet) Dense Graded Conventional Dense Graded LA CRM (10% Rouse, Wet) Dense Graded CRM (17.5% Arizona Ai Wet) )Gap GradedG d Conventional Dense Graded US CRM (1% Rouse, Dry) Dense Graded CRM (2% Generic, Dry) Gap Graded Conventional Dense Graded

5 Roadway Core Air Voids (5 7 years of service)

6 Comparisons of Field Performance Roadway core air void analysis Rut depth measurement International Roughness Index (IRI) DYNAFLECT system structural numbers Quality Control/Quality Acceptance data LA Pavement Management Section visual data

7 Lab vs. Field Performance Indirect Tensile Strength (ITS) and Resilient Modulus (M R ) measurements were compared against field performance Only a few showed good correlations and are noted throughout the presentation

8 US 61 Traffic and Mix Design Year/ADT % Truck Structural Number (SN) 1992/ Polymer Gap Graded CRM Gap Graded CRM OGFC Gradation (% Pass) Polymer Gap Graded CRM Gap Graded CRM OGFC Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids No Stability (Lbs) No Flow (1/100) No % AC

9 US 61 IRI

10 US 61 Random Cracking (0.50) (0.76) (0.83) (1.61) (ITS Strain)

11 US 61 Rut Depth

12 LA 1040 Traffic and Mix Design Year/ADT % Truck Structural Number (SN) 1993/ PlusRide Gap Graded Conventional Gradation (% Pass) PlusRide Gap Graded Conventional Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids No Stability (Lbs) No Flow (1/100) No % AC

13 LA 1040 IRI

14 LA 1040 Random Cracking

15 LA 1040 Rut Depth

16 US 84 Traffic and Mix Design Year/ADT % Truck Structural Number (SN) 1994/ Neste Wright CRM Conventional Gradation (% Pass) Neste Wright CRM Conventional Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids No Stability (Lbs) No Flow (1/100) 10 8 No % AC

17 US 84 IRI

18 US 84 Random Cracking

19 US 84 Rut Depth

20 US 167 Traffic and Mix Design Year/ADT % Truck Structural Number (SN) 1994/ % Rouse CRM 2% Generic CRM Conven. Gradation (% Pass) 1% Rouse CRM 2% Generic CRM Conven. Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids No Stability (Lbs) No Flow (1/100) No % AC

21 US 167 IRI

22 US 167 Random Cracking

23 US 167 Rut Depth

24 LA 15 Traffic and Mix Design Year/ADT % Truck Structural Number (SN) 1994/ Rouse Dense Graded CRM Gap Graded Conven. Gradation (% Pass) Rouse Dense Graded CRM Gap Graded Conven. Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids No Stability (Lbs) No Flow (1/100) No % AC

25 LA 15 IRI

26 LA 15 Random Cracking (0.68) (0.67) (1.92) (ITS Strain)

27 LA 15 Rut Depth

28 Pavement Condition Index

29 ITS Strength

30 ITS Strain

31 Summary of Results Conventional mixes showed higher laboratory performance CRM mixtures show better field performance (rut depth, random cracks, and IRI) than corresponding control section Both CRM wet and dry performed equally well or better than conventional mix types Including CRM significantly increases costs

32 Summary of Results After 7 to 10 years of service: CRM sections exhibited similar or lower IRI than control section CRM sections generally exhibited similar or lower rut depth than control section CRM sections generally exhibited similar or less distress cracking than control section

33 Recommendations CRM wet process to be implemented Shown to be excellent method for reducing traverse crack propagation in composite pavements Improves actual pavement performance Should increase life cycle of HMA pavements Increased use of this process will significantly decrease based on increased usage of process

34 DOTD Pavement Research Facility

35 Experiment 2: Comparative Performance of Conventional and Rubberized Hot Mix Asphalt Lane 1 Lane 2 Lane 3 (control) PRM Wearing Course PAC 40 Binder Course PAC 40 Wearing Course AC30 Base PRM Base AC 30 Base Stone Base Soil Cement Working Table PRM: Powdered Rubber Modified

36 Experiment 2: Comparative Performance of Conventional and Rubberized Hot Mix Asphalt Rut Depth (in.) Rubberized wearing course Conventional asphalt mix Rubberized base course Cumulated 18-kip ESALs (million)

37 Experiment 2: Comparative Performance of Conventional and Rubberized Hot Mix Asphalt Implementation Recommendation: Modify Asphalt base course specifications to require rubberized asphalt or polymer modified asphalt T8 WC-PRM T8 WC Base PRM Base in permanent strai cycles

38 Life Cycle Cost Analysis Low Volume Road 2:1 EASL advantage Initial Construction $236,401/ln mi Mill 2 & Overlay 3.5 $66,965 $66,965 Modified Asphalt Base (40 yr design life) Annualized cost = $18,702 / ln mi / yr AC 30 Asphalt Base (30 yr design life) Initial Construction Mill & Overlay Mill 2 w/ Structural Overlay 7 $230,936/ln mi $66, % $126,046 savings Annualized cost = $21,409 / ln mi / yr 40

39 Implementation I 12 Millerville and I 10 Sorrento

40 Implementation Dry Process Dry Process I 12 Baton Rouge

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42 I 12 SMA Hamburg (LWT) 15%CRM Dry Process w/ Vestenimer Average e Rut (mm) PG w/ 15% CRM PG 70 22m w/ 15% CRM Number of Passes

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44 Implementation Wet Process PG 82-22rn Blended at Contractors Tank I-10 Gramercy to Sorrento

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46 I 10 SMA Hamburg (LWT) 12 ut (mm) Average R PG82 22RM PG76 22m (conv.) Number of Passes

47 I 10 and I 12 Mix Design I 10 I 12 Gradation (% Pass) I 10 I 12 Spec. Gravity ¾ Theo. Gravity ½ % Theo. Gravity / % VMA No % VFA No % Air Voids Vid No % AC No Density (lb/ft 3 ) No No No

48 LOUISIANA SUPERPAVE BINDER SPECS PG 82-22RM PG 76-22M PG 70-22M PG 64-22* High Volumn High Volumn Low Volumn Base mix ORIGNIAL BINDER FLASH POINT, 230 C Max., ROTATIONAL VISCOSITY, 135 C, 3 Pa * S, Max., DSR, G*/Sin Specified High Temp., 1KPa, Min. (1.3 K Pa for PG64-22) RTFO aged; (1% Max. Loss in RTFO) DSR, G*/Sin Specified High Temp., 2.2 KPa, Min. PAV aged, (uniform specs for all - 22 grades) 25 C, G* x Sin Delta, = 5000 KPa Max.; (4000 max for 64-22) C, 300 MPa max stiffness and minimum slope of *Note: PG required when 21-30% RAP is used in base course mixes.

49 LOUISIANA SUPERPAVE BINDER SPECS, Modified Requirements Original Binder: Separation Test, 2 C max. difference on ring and ball PG76 22m; Force 4 C, 30 cm: F 2 / F 1 = 0.3 Min. PG 70 22m; Force 4 C, 30 cm. = 0.5 Lb. Min RTFO material: Elastic Recovery, Min. Recovery at 25 C, PG 82RM and PG76m 60% Min PG70m 40% Min

50 I 10 Binder Test Results sampled from contractors blend tank Original Binder 82C G*/Sin delta = 1.13 RTFO G*/Sin Delta = % Elastic Recovery

51 Observations PG76 22m (SBSmodified) mixturesset set laboratory performance standard. Dry Process and Wet Process Rubber Modified Asphalt have recently performed well in SMA. And should also be allowed in dense graded mixtures PG 82 22rm 22 is equal to PG 76 22m.

52 Thank You!