Full Depth Reclamation - Colorado Asphalt Pavement...
Transcript of Full Depth Reclamation - Colorado Asphalt Pavement...
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Full Depth Reclamationp
METROPOLITAN GOVERNMENT PAVEMENT ENGINEERS COUNCIL17TH ANNUAL GENERAL COUNCIL MEETING ANDCOMPREHENSIVE PAVEMENT INFORMATION SESSIONS
*Definition from Asphalt Recycling & Reclamation Association
Full Depth Reclamation* (FDR) Rehabilitation technique where full thickness of asphalt pavement & predetermined portion of underlying materials are uniformly pulverized & blended to an upgraded, homogenous base material
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Definitions
Stability - Ability of asphalt mixture to resist deformation from imposed loads;
Unbound, non stabilized material
resist deformation from imposed loads; dependent upon both internal friction (aggregate structure) & cohesion (binder)
Bound - Particle structure strengthened with a binding medium such as asphalt or cement
Stabilization - Mechanical, chemical or bituminous treatment designed to increase
Bound, stabilized material
bituminous treatment designed to increase material stability or otherwise improve engineering properties
DefinitionsMechanical stabilization - 1st step in reclamation; Mechanical stabilization - 1st step in reclamation; also used to describe FDR without addition of binder (Pulverization)
Chemical stabilization - FDR with chemical additive (Calcium or Magnesium Chloride, Lime, Fly Ash, Kiln Dust, Portland Cement, etc.)
Bituminous stabilization - FDR with asphalt emulsion, emulsified recycling agent, or foamed / expanded asphalt additive
Combination stabilization -Any 2 or more of above
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Project Analysis‐Design
• Needed for pavement design▫ Pavement design is necessary
• If not assessed▫ Weak areas or thicknesses variability won’t be▫ Weak areas or thicknesses variability won t be known until construction
1. Ideal Pavement & Material Assessment
• Springtime (preferred) structural l ti bevaluation by agency or
consulting engineer ▫ Structure; layer evaluations▫ Drainage▫ Distresses▫ Road needs
Dynamic Cone Penetrometer (DCP)
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Ideal Pavement Assessment
• Soil borings▫ Sample top 6‐10 inch▫ Auger to 5 ft for layer
thickness & identification & water table location
• Strength testing options identify weak areas & determine subgrade strength/modulus▫ Falling Weight Deflectometer (FWD)▫ California Bearing Ratio (CBR) or
R V ltable location R‐Value▫ Dynamic Cone Penetrometer (DCP) ▫ Proof rolling (granular surfaces only)
Falling Weight Deflectometer - FWD
CBR device
R-ValueDetermination
(Hveem)
Typical costs
• Coring ‐ $1,000 to $1,500 (<2‐mile project)(<2 mile project)
• Soil / pavement borings ~$1,000 per mile• FWD w/ analysis ‐ $4,000 to $6,000• Sampling & sub grade testing ‐ $2,500
(<2‐mile project)• DCP ‐ equipment costs $1 500DCP equipment costs $1,500
Costs will vary depending on many factors, especially mobilization and traffic control
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Performance‐Related Specification Guidelines
Determine if appropriate early curing is occurring
Short Term Strength byCohesiometer ASTM D1560
Performance ParameterCriteria
Indirect Tensile Test (IDT)
Relative indicator of qualityStrain or deflection w/ applied
load for structural design
Resilient Modulus ASTM D4123
Resistance to moisture damage
Retained Strength ASTM D4867
g gCohesiometer ASTM D1560
Tests run on 150-mm SGC prepared specimens
Thermal cracking resistanceIndirect Tensile Test (IDT) AASHTO T 322
ReliabilityConstruction & QA/QC Requirements
Engineered Emulsion Technology
F l t d f • Formulated for: • Chemical break /Solvent less ▫ Earlier strength than conventional emulsions▫ Adhesion characteristics▫ Resistant to moisture damage▫ DispersionDispersion
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Engineered Emulsion Technology, cont.
• Formulated for:Hi h h lt t t• High asphalt content ▫ Good dispersion with higher film thickness
▫ Durable▫ Flexible
• Climate‐specific binderF l t d f h EEFDR• Formulated for each EEFDR project (SHRP)
Engineered Mix Design
• Virgin aggregate or RAP may be• Virgin aggregate or RAP may be needed▫ To increase depth of finished structural layer
▫ To improve gradationCleanliness (P200)Material qualityGradation
Add rock
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Equipment
Reclaimer
Reclaimer
• Typically used in FDR & GBS construction
• Typical properties:▫ Center mount cutter
Generally up cuts
▫ Accurate emulsion addition
▫ 8‐ or 10‐ft wide▫ Emulsion added to enclosed mixing drum
▫ Road is usually reclaimed a third at a time (24 ft wide, 8‐ft wide milling head)
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Construction Production Rates
• Typical production rates▫ Reclaimer rate (~30‐90 ft/min)▫ Daily production approximately 0.5 ‐ 0.75 centerline miles (reclaimer)
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Profiling ‐ Pre‐pulverization
• Pre‐pulverize, blade & lightly compact before reclamation
▫ Aids in material sizing
▫ Corrects road profile if required
▫ Adjust for additional moisture to facilitate in mixing and compaction
▫ May not be required with some reclaimers
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EEFDR process
Compaction
CompactPadfoot roller
Blade to desired profile & remove pad marks
Final compaction ‐ pneumatic and/or steel rollers
• Cover with appropriate wearing surface after curing
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Pad foot Compactor
• Best for achieving compaction at bottom of layer• High amplitude/ low frequency• Back drag blade preferred• 28,000 lb ‐ 34,000 lb
Motor Grader to Remove Pad MarksLevel Surface
Stephenson County, IL
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Finishing Rollers
Achieve surface compaction & final appearance
• Pneumatic roller▫ 20‐ton minimum▫ 90 psi tire pressure
Vibratory steel roller▫ 10‐ton minimum▫ low amplitude/ high frequency
Field Testing ‐ Quality Control
• Specific tests & testing frequency determined by agency & road requirements▫ Moisture content▫ Depth▫ Top sizeE l i t t▫ Emulsion content
▫ Compaction▫ Modified Proctor for target density
▫ Return to traffic
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Benefits,• Construction
‐ Immediate compaction
‐ Traffic return usually same day
‐ Overlay within 1‐2 weeks (or sooner)‐ Depends on weather & moisture
‐More uniform strength
‐ Increased structural capacity‐May reduce overlay thickness need
Benefits contd,
• Performance
‐ Flexible‐ Reduced moisture sensitivity‐ Resistance to cracking (fatigue)‐ Improved low temperature cracking‐ Same composite sectionp‐ 100% recyclable
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Structural Benefit
• The EEFDR process will increase the structural coefficient of the material
• The structural coefficient of EEFDR materials is dependent upon:▫ Amount of P200 (fines)▫ Angularity of existing material
Existing 2” Mill/Overlay2”Mill/Overlay
6” FDR
2” New HMA ( SN 88)3” HMA (SN .72)
6” Base (SN .72)
Total SN 1.44
2” New HMA (SN.88)
1” Old HMA (SN.24)
6” Base (SN.72)
Total SN 1.84
2 New HMA ( SN .88)
6” Full Depth (SN1.50)Reclamation
1” Base (SN.12)
Total SN 2.50
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Builds structure down into pavement
STA 0343‐027~US34 asphalt overlay, HMA, Full Depth Reclamation,
• Square yards (25,812) for the FDR section totaled 3.7 lane miles.
• (Included shoulders)• •$74,648.98 per lane mile for 8”• •$9,331.12 per inch/lane mile• •Square yard equals $10.60 per s yd. or $23.56 per ton (11,600 tons) 465 TL
• > Structural number = 2.00 for FDR
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18th Annual “Best in Colorado” Asphalt Pavement Awards Dinner & Program
BEST OVERALL QUALITY Innovative Technology (Asphalt Emulsion and Full Depth Reclamation and US Highway 160 East - Aztec CreekMP 11.5 – 17.97Contractor: Four Corners Materials Contractor: Four Corners Materials Construction Manager: SEMA ConstructionOwner: CDOT Region 5
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CDOT NH 1601‐061 US 160
• 310‐00610 Full Depth Reclam. of HMA 159,931 SY $2.75 $439,810.00
• 310‐00700 Asphalt Emulsion Full Depth 156,030 SY $2.50 $390,075.00
• 411‐90040 Recycling Agent 517,637 GAL $1.75 $905,864.75 ($5.81 SY)
• $11.06 per s. yd.
Comparisons (Phase 1) $2,783,010 @ $39.40
Description Units Unit Bid Project
Price Quantity TotalAggregate Base Course (Class 2) TON $13 30,620 $398,068 Aggregate Base Course (Class 6) TON $21 7,857 $165,017
Full Depth Reclamation of HMAReclamation of HMA Pavement (0-8") SY $2.80 70,639 197,013HMA (Grading SX) (75) TON $54 25,380 $1,370,521 Asphalt Cement Performance Grade (PG 64-22) TON $460 1,390 $638,781 Emulsified Asphalt (Slow-Setting) GAL $5 2,722 $13,611
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Comparisons (Phase 2) $5,846,396 @ $37.58
Description Units Unit Bid Project
Price Quantity TotalAggregate Base Course (Class 3) TON $16 58,795 $712,402 Aggregate Base Course (Class 6) TON $19 47,571 $585,323 Full Depth Reclamation of HMA (8-12") SY $2.75 159,931 $427,828 Asphalt Emulsion Full Depth Reclamation SY $2.50 156,030 $388,935 Hot Mi AsphaltHot Mix Asphalt (Grading SX) (75) TON $47.50 34,228 $1,686,461 Asphalt Cement Performance Grade (PG 64-22) TON $480 2,304 $1,135,348 Emulsified Asphalt (CSS-1H) GAL $4 7,848 $39,200
City of Las Vegas - MLK Case Study Resource Usage
Reconstruction Option
Milling 36,749 Tons 1400 Tons / Day 26 Days Excavation 62,578 CY 1400 CY / Day 45 Days Type 2 road base 96,941 Tons 1400 Tons / Day 69 Days Hot Mix Asphalt 42,874 Tons 2500 Tons / Day 17 Days
Reconstruction Option 157 Days
FDR Option
Milling 36,749 Tons 1400 Tons /Day 26 Days Excavation 19,712 CY 1400 CY /Day 14 Days Type 2 road base 11,405 Tons 1400 Tons /Day 8 DaysPre‐pulverize material 25,031 CY 1400 CY /Day 18 DaysFDR material 25 031 CY 1400 Cy /Day 18 DaysFDR material 25,031 CY 1400 Cy /Day 18 Days Hot Mix Asphalt 36,749 Tons 2500 Tons /Day 15 Days
FDROption 99 Days
• 85,536 tons of additional Type 2 would have been needed using the traditional reconstruction method
• Using the FDR method saved more than 6,800 truck trips
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• They total $170,909.94 divided by 15,450 square yards come out to $11.06 per square yard.
•• 15,450 square yards equals 2.19 lane miles which comes out to $78,041.07 per lane mile (7,040 square yards per lane mile).
•
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HMA @ SN .44 Per Inch(Costs Per S. Yd.)
HMA $$$ per ton SN 1.00 SN 1.50 SN 2.00
$50.00 $6.32 $9.49 $12.66
$75.00 $9.48 $14.23 $18.98
$100.00 $12.64 $18.98 $25.31
$125.00 $15.80 $23.72 $31.64Note:SN 1.00 = 2.25” overlay thicknessSN 1.50 = 3.50” overlay thicknessSN 2.00 = 4.50” overlay thickness
MEPDG ConsiderationsMEPDG Considerations
Future Design GuideFuture Design Guide
Material Properties:• Level 1 – measured▫ Dynamic Modulus E* input is criticalis critical
• Level 2 – estimated• Level 3 ‐ defaults
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φ/ωσosinωt
Compressive Dynamic Modulus Compressive Dynamic Modulus (|E(|E*|) *|)
• Asphalt Mixture PerformanceTester (AMPT)
•Input into the new pavement design
Time, t
εosin(ωt-φ)
σ, εσ0 ε0
p p gguide (MEPDG)
•AASHTO TP-62•Modulus – Rate of change of stresswith strain (4°C, 20°C, & PG High)
0
0|*|εσ
=E itωφ =
FDR Dynamic Modulus ResultsFDR Dynamic Modulus Results
100,000 A:75% RAPA:25%RAP
Emulsion FDR Mixtures
1,000
10,000
Dyn
amic
Mod
ulus
, M
A:25% RAPB:75% RAPB:25% RAPB:25%RAP;1%cA:25%RAP;1%c19 mm HMA
100
1,000
1.E-05 1.E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07
Reduced Frequency (Hz)
D
FDR “stiffer” than HMA at low frequency or warm temperatures
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CIR Dynamic Modulus ResultsCIR Dynamic Modulus Results10,000,000
19 mm AC (PG 64-22)
10,000
100,000
1,000,000
Dyn
amic
Mod
ulus
, E* (
p
MEPDG - CIR
MEPDG - FDR
12.5 mm AC (PG 64-22)
1,000
,
1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07
Reduced Frequency (Hz)
16 Kansas Projects
MEPDG Default values are low
Questions ???