Santa Clara County. Rubberized Asphalt Concrete (RAC) Theron Roschen, PE - Quincy Engineering

Transcription

1 Santa Clara County Rubberized Asphalt Concrete (RAC) Theron Roschen, PE - Quincy Engineering With assistance from: The California Department of Resources Recycling and Recovery (CalRecycle)

2 Why choose asphalt rubber? Less maintenance Resistance to reflective cracking Established life cycle cost-effectiveness Can be used in reduced thickness Proven alternative to costly reconstruction Quieter pavements (4dB 6-years post overlay)

3 NO COST TECHNOLOGY TRANSFER THROUGH Seminars Field Assistance Technical Reviews Guidelines Grant Assistance

4 California Scrap Tire Overview Generates million scrap tires/year $1.75 per tire collected from CalRecycle Grants

5 Asphalt-Rubber as defined by ASTM D8-88 Asphalt-Rubber is a blend of asphalt cement, reclaimed tire rubber and certain additives, in which the rubber component is at least 15% by weight of the total blend and has reacted in the hot asphalt cement sufficiently to cause swelling of the rubber particles.

6 Type 1 Asphalt-Rubber Binder - Paving grade asphalt and reclaimed vulcanized rubber. Type 2 Asphalt-Rubber Binder - Paving grade asphalt, extender oil, high natural and reclaimed vulcanized rubber. Terminal Blend - Paving grade asphalt, polymers, and reclaimed vulcanized rubber digested into asphalt at the refinery

7 80% +/- 2% of total binder 20% +/- 2% of total binder Paving Asphalt AR-4000 Asphalt Modifier (extender oil) 2.5% to 6% by weight of paving asphalt High Natural Rubber 25% +/- 2% of total rubber Scrap Tires 75% +/- 2% of total rubber Type II Asphalt Rubber

8 Terminal Blend Tire Rubber Asphalt Recycled tire rubber completely digests tire rubber particles into an asphalt binder Refined for 16 hours, under pressure and temperature Non proprietary Meets PG grading system Material comes ready to use upon arrival Polymers may be added Meets CalRecycle Grants

9 Viscosity is what defines Asphalt-Rubber Binder Asphalt-Rubber 1,500 to 2,500 Centipoises At 375 Extremely Viscous Rubberized Asphalt Terminal Blend 300 to 600 Centipoises At 325

10 Granulation 2 Inch Chips Reduced to ¾ Inch While Separating Steel

11 Granulation ¾ Inch Reduced to 3/8 Inch While Separating Fabric and Steel

12 Finish Product and Bagging

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14 Ground tire rubber in 2,000 pound Supersacks

15 Rubber is fed from the weigh hopper into a high shear mixer.

16 liquid asphalt and modifier at 375 to 425 F

17 Aggregate Gradation Comparison Open Graded Gap Graded Dense Graded

18 % Passing Composite Power 45 Chart 100 Maximum Density Gap Grade 80 Dense Grade Open Grade SMA RAC Presentation 12.7 West 19 Covina 25 January 27,

19 HMA vs. RAC RAC Presentation West Covina January 27,

20 Cost Factors When AR is in production the plant can not make conventional Haul distance and ambient temperatures Traffic control for cooling time KLEINFELDER Mike Robinson Lincoln / Rocklin PMAR March 5,

21 Contractor s Cost Issues Small Projects = LARGE UNIT COSTS!! Expensive move-in Agencies can save $$ with coordination/procurement Follow Caltrans Bidding in the Winter will allow efficient scheduling for the upcoming season Be flexible KLEINFELDER Mike Robinson Lincoln / Rocklin PMAR March 5,

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24 Design of Asphalt Rubber Pavements Uses a deflection based design method Up to 50 % reduction in thickness compared to conventional AC design thickness to retard reflective cracking Over 1000 reduced thickness projects KLEINFELDER Mike Robinson Lincoln / Rocklin PMAR March 5,

25 Heavy Vehicle Simulator UC Davis

26 Heavy Vehicle Simulator UC Davis

27 Page 27 Agenda

28 3 Conv. AC 1 1/2 ARHM 1 ARHM

29 Performance in Indio, CA

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31 SHOULD BE A MINIMUM OF 315 F LEAVING PLANT Temp of ARHM-GG

32 Virgin Asphalt Temp: Reaction Temperature: Mix Plant: 1 st Breakdown: All compaction: Ambient/Surface Temp: >375 F F F >280 F >250 F >55 F RAC Presentation West Covina January 27,

33 Multicool 55 o, 5 mph wind, 2 less than 10 minutes RAC Presentation West Covina January 27,

34 65 o Ambient & Surface, 5 mph wind Temp ( o F) " 1.5" 1.2" 1" Minutes RAC Presentation West Covina January 27,

35 But it s not just cooling RAC Presentation West Covina January 27,

36 But it s not just cooling Roller Not enough densification here Too thin and too cold here RAC Presentation West Covina January 27,

37 StreetSaver PCI Curve Pavement Condition Index (PCI) Asphalt Rubber vs. Conventional for Arterial Streets About 300 data points Conventional HMA Family Curve New RAC Family Curve Age of Pavement (Year) 37

38 RAC pricing can be volatile based on many factors: Cost of Oil Tonnage Bid Blender Availability Geographic Location Urban vs. Rural Locations Contractor Familiarity Proximity of Crumb Plants Haul Distance to Site Seasonal Temps Terminal Blend RAC vs. Field Blend RAC

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40 310 Caltrans and local agency projects were analyzed: The average of all projects - RAC projects cost 15.5% higher. ($95.40 per ton vs. $80.55 per ton) The differential between RAC and conventional has been trending down by 29% over the past 3- years. The average differential between RAC and conventional for local agency projects was approximately $20 per ton. For lower tonnage projects (3,000 to 7,000 tons), the average cost increase was 14.5% higher than a 12,000 ton project.

41 Statewide Local Streets and Roads Needs Assessment

42 Cities (44%) and counties (37%) own and maintain 81% of California s roads ~ 143,000 centerline-miles In 10 years - 25 % of roads will be in failed category Current funding for local system is $2.5 billion a year Status quo will require an additional $1.9 billion a year Shortfall >$82 billion over the next 10 years to bring the system up to date

43 National Transportation Group (TRIP): Added cost to California drivers up to $800 per year in repair and other costs International Pavement Management Assoc.: Replacement value of roadway is $50 per SY. Maintenance should be 1.5% of the replacement value annually to keep PCI as is

44 How Did We Get Here? Population grew from 30M 1990 to 38M (27%) New regulations ADA, NPDS, name your poison Last 15 years, paving costs have increased more than eight-fold Gas tax has not increased in over 20 years, EV s, Hybrids Every additional dollar invested will result in cost savings of almost $2.

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47 350 o F Stir binder Read peak viscosity Average 3 readings Viscometer Testing

48 Process Plant Check plant certification Samples Paving asphalt Crumb rubber AR binder Aggregate Certificates of Compliance Temperatures Plant, site, screed, rollers

49 SHOULD BE A MINIMUM OF 315 F LEAVING PLANT Temp of ARHM-GG

50 Virgin Asphalt Temp: >375 F Reaction Temperature: F Mix Plant: F 1 st Breakdown: >280 F All compaction: >250 F Ambient/Surface Temp: >55 F (higher temperatures recommended)

51 INSPECTION AT THE JOB SITE PRIOR TO PAVING Pre-Construction Meeting: Approved mix design Surface preparation Delivery method Rate of delivery Equipment in good working order Number and type of rollers Acceptance Testing Other Issues (Refer to A-R Design Guide) Ambient and surface temperatures (>55 ο F)

52 Surface Preparation Cracks filled in advance? R & R obvious subgrade failures Leveling course Remove thermoplastic markings Mill conforms at curb and end match Sweep / power wash

53 Surface Preparation Clean & Dry Tack Uniformly applied No more than necessary Emulsions must break before paving Coldmilled surfaces Texture provides aggregate interlock Application of tack can be tricky

54 Automated ski Windrow/pick-up machine or end dump Pave on lane lines Slow down the paver Extra Roller? Keep traffic off till 150 F Consider I/S closure and/or night paving if ambient met

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58 Application 375 o F to 400 o F 0.60 to 0.65 gallons/sy 70% Embedment

59 (Hot Pre-Coated Aggregate)

60 Aggregate 3/8 and ¼ Precoated w/ 0.5 to 1.0% PG binder Supplied to project at 225 o F to 325 o F lbs/sy Clean & dry Apply IMMEDIATELY!

61 Rollers Minimum of 3 pneumatic 3,000 lbs/wheel minimum 90 psi minimum, or foam-filled 1 steel drum

62 Set & Cure Time No traffic of any kind for at least 15 minutes No traffic other than necessary haul traffic on either seal coat for at least 25 minutes. Keep speeds below 10 mph Sweep 1 hour and next day

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66 Double Chip Seal Two Layer System

67 SAMI - Stress Absorbing Membrane Interlayer Pre-existing Pavement AC or ARC Overlay

68 SAMI in a three layer system AC or ARC Overlay SAMI Leveling Course Pre-existing Pavement

69 Noise Reduction and Asphalt Rubber

70 Vehicle-generated noise comes from: engine, exhaust system, aerodynamic noise tire noise. Power train noise External factors For > 30 mph, pavement/tire noise dominates.

71 Walls Effective only for those in line-of-sight. Do not reduce noise at source.

72 A reduction of 3 db(a) is like doubling the distance from the noise, reducing traffic volume by 50%, or reducing traffic speed by 25% 67 db(a) - 3 db(a) = 64 db(a) 100 ft

73 6-year Noise Study Reduction compared to pre-overlay condition Alta Arden AR 1month -6dB 16 months -5dB 6 years -5dB Antelope* AR 6 months -4dB * (speed increase) 5 years -3dB Bond CA 1 month -2dB 4 year 0dB

74 ADOT included rubber asphalt surfacing as a pavement preservation strategy. Independent studies indicate a noise reduction up to 4.5 dba using rubber asphalt.

75 Rubberized Asphalt Concrete Grants Max. grant is $250,000 Program Currently Being Updated Next Cycle August

76 Rubberized Asphalt Concrete Grants: AB 513 (Frazier), grant program will change for the FY 2014/15 solicitation Fixed amount $10 per ton up to $250,000 (3,500 ton min) Chip Seals $0.50 per SY up to $250,000 (40,000 SY min) Prior Grantees eligible 2 to 3 prior grants $7 per ton > 4 prior grants $4 per ton If Budget Proposal approved, a total $8 million available

77 Rubberized Asphalt Concrete Cooperative Purchasing Program (RCPP) 2013

78 New Program, But Not a New Concept Sacramento County Implemented a RCPP Net RAC savings was 15% Introduced new bidders Eliminated Project Delays due to Unavailability of the Mobile Blender Units

79 RCPP Overview Slide 79

80 Quals: New RAC Champion Requirements 1+yrs. experience with RAC and completed 1 or more RAC projects Supports 1 to 3 RCPP Partners RCPA in excess of 15,000 tons RAC, minimum of 2,000 tons/day Each Qualifying New Partners must account for 15% of total RAC Provide a RCPP Final Report for CalRecycle Reimbursements RCPP Reimbursements ranging from $80,000 for one partner up to $200,000 for 3 participants RAC Partner RCPP Reimbursements ranging from $25K for each partner using 3K tons of RAC to $50K for each partner using 7.5K tons of RAC Services valued at approximately $116,000 Cannot be receiving funds through the RAC Grant Program

81 Quals: Experienced RAC Champion Requirements 3+yrs. experience with RAC and used at least 15,000 tons of RAC Supports 2 to 3 RCPP Partners RCPA in excess of 20,000 tons RAC, minimum of 2,000 tons/day Each Qualifying New Partners must account for 15% of total RAC Provide a RCPP Final Report for CalRecycle Cannot be receiving funds through the RAC Grant Program Reimbursements Experience RAC Champion RCPP Reimbursements ranging from $122,500 for 2 partners up to $175,000 for 3 partners RAC Partner RCPP Reimbursements ranging from $25K for each partner using 3K tons of RAC to $50K for each partner using 7.5K tons of RAC Services valued at approximately $88,000

82 Questions? Theron Roschen, PE Quincy Engineering Questions? Questions? Page 82