MnPavement Rehabilitation Best Practices LRRB Inv 808

Transcription

1 MnPavement Rehabilitation Best Practices LRRB Inv 808 Gene Skok (UofM) Shongtao Dai (MnDOT( MnDOT) 12 th Minnesota Pavement Conference February 14, 2008 Mn/DOT Office of Materials and Road Research

2 Outline Objectives Literature Review Types of Reclamation Definition of Factors Decision Checklists Criteria Recommendations

3 Pavement Rehabilitation (LRRB INV 808) Objective Laying out the Best Practices for the selection of asphalt concrete recycling techniques: Full-Depth Reclamation (FDR) Cold In-place Recycling (CIR) Mill/Overlay (M&O).

4 Why Mill and Overlay? Low Initial Cost Minimize clearance/grade issues Construction time minimized Covers up reflective cracks

5 Rehabilitation Decision Factors Existing Conditions (PQI) Ride (RQI) Surface Rating (SR) Transverse Cracks (0.01, 0.10, 0.20) Long. Cracks & Deter. (0.02, 0.03, 0.04).

6 Rehabilitation Decision Factors (cont.) Multiple Cracking (0.15) Alligator Cracking (0.35) Rutting (0.15) Raveling & Weathering (0.02) Patching (0.04) PQI = (RQI X SR) 1/2

7 STRUCTURAL ADEQUACY TONNAGE PAVEMENT THICKNESS DESIGN Soil Factor (GE vs HCADT) R-Value (GE vs ESAL s) Mn/PAVE (Thickness vs Load Spectra)

8 Pavement Rehabilitation Database Location Original Pavement Construction Pre-Rehab Rehab Post-Rehab

9 Pavement Rehabilitation Database

10 MN Rehabilitation Projects Surveys District 2 District 1 CIR (37) District 4 District 3 FDR (41) M&O (25) District 8 Metro District 7 District 6

11 SR Values Pre-Rehab. SR Values 4 for C.I.R. Projects SR FDR Average Project

12 Pre Rehabilitation SR Value for FDR SR Values 4 Projects SR FDR Average Project

13 Pre-Rehabilitation SR Value for Mill and Overlay Projects SR levels SR M&O Average Project

14 SR Values before and Degradation Curves after Rehabilitation SR CIR FDR Med. M&O Thick M&O Year from rehab

15 Surface Rating (SR) Degradation Rates Rehabilitation Procedure Cold In-Place Recycling Full Depth Reclamation Thin Mill & O.L. Medium Mill & O.L. Thick Mill & O.L. Deterioration Rate

16 SR Values for Individual Degradation curves FDR Projects SR Before/After (FDR) SR Year Relative to Rehab

17 Transverse Cracking IWD. for FDR Projects Condition Histories Transverse IWD Transverse Distress (CIR) Year Relative to Rehab

18 Transverse Cracks I.W.D. for S.R. Level TC effect on SR Transverse Crack IWD CIR FDR M&O Typical Overall SR

19 Decision Check Lists 1. Geometrics 2. Pavement Condition (s) 3. Review Figure 3.7 (PQI < 2.5) 4. Structural Adequacy a. Pavement Thickness b. Tonnage c. Falling Weight Deflectometer

20 Geometrics Checklist Clearances Shoulder Width Grading Width Curb and Gutter Constructability

21 Geometrics 3.6 GEOMETRIC CONSIDERATIONS NOTE: Official State Aid rules can be found directly at ype=rule_chap&year RULE_CHAP&year=current&chapter=8820 OR by browsing to and then selecting: Statues, Session Laws, and Rules Under the Minnesota Rules section on the main page, Retrieve an entire chapter Enter in the number 8820 and click Get Chapter

22 Table 3.6. Pavement Condition(s) ) Checklist Ride Quality Index (RQI) 1.Methoda. Pavement Conditions 1. Using Mn/DOT Van 2. Rating Panel Checklist Critical Value 2. Rated by a panel Surface Rating (SR) Condition Individual Weighted Distress (IWD) 1.Rut Depth 2.Transverse Cracking a.low Severity b.medium Severity c. High Severity Total T.C. IWD 3. Long. Cracking/ Joint Det. 4. Alligator Cracking 5. Raveling, Weather, Patch Total IWD SR PQI Discussion

23 Selection of Rehabilitation Procedure based on Surface Procedure Selection Ratings Selection of Rehabilitation Procedures based on Surface Conditions For SR =< 2.5 IWD(Mult) > 5 and/or IWD(Trans) > 5 HMA > 4 FDR CIR Expected Life (see Table 3.3 and 3.6) HMA < 4 FDR IWD(Mult) < 5 and IWD(Trans) < 5 RQI > 3.0 Thin M&O RQI < 3.0 Med. or Thick M&O

24 Structural Adequacy Table 3.7 Summary of Structure Adequacy. PAVEMENT THICKNESS 1. Design Procedure: a. Soil Factor, R-Value R, Mechanistic b. Soil Type (Classification) AASHTO Class R- Value Measured Estimated Resilient Modulus Measured Estimated c. Traffic (20 year Predicted): AADT HCAADT ESAL s d.required Thickness (Granular Equivalent Thickness) Soil Factor Procedure R-Value Procedure Mn PAVE NOTES

25 SPECIFIC CRITERIA 1. Is existing HMA thickness adequate to support CIR equipment? (3.5 in.)? 2. Is existing subgrade stiffness adequate to support CIR equipment? (5000 psi)? 3. Consider SR degradation rate.

26 Criteria Continued 4. If not structurally adequate then CIR should NOT be used without additional overlay 5.If SR < 2.5 and IWD for multiple cracking or T.C. > 5.0: - Mill and OL should not be used - if existing HMA > 3.5 in. use FDR or RIC - if existing HMA < 3.5 in. use FDR only

27 Criteria Continued more 6. If the SR < 2.5 and Mult.. or Transverse cracking IWD is < than 5.0, use mill & overlay 7. Finally, cost/benefits should be considered along with decay rates in the final decision. NOTE: T.C. IWD = 5.0 for a pavement with all medium severity T.C. represents a crack count of 50 cracks per 100 ft. An IWD = 5.0 for a pavement with all high severity T.C. represents a crack count of 25 cracks per 100 ft.

28 RECOMMENDATIONS Determine ride (RQI) periodically with Mn/DOT IRI correlation(s) ) or panel Determine IWD and SR using Mn/DOT Distress Manual periodically Run FWD periodically to determine: - Tonnage - Subgrade Stiffness - GE of pavement section

29 RECOMMENDATIONS (cont.) 4. Continue documenting performance information from 1., 2., and 3. in the rehabilitation database (?) - include RQI, SR (IWD s( IWD s), GE, Soil Stiffness. This could be part of the PMS or Mn/ROAD database (s).

30 Summary Types of Reclamation Decision Factors Database Development Decision Checklists Criteria Recommendations

31 Acknowledgements Minnesota Local Road Research Board Technical Advisory Committee Mn/DOT, Dave Janisch, Erland Lukanen, Graig Gilbertson,Perry Collins Counties, Brian Noeltzman,Wayne Olson,Milt Hagen,Brad Wentz,Brian Shepard,Kathy Jaschke,Darrell Pettis, Curt Bolles,, Guy Kohnlhofer, Midwest Construction, Tom Olson,American Engineering, Dave Rettner,, SEM Materials,Dan Wegman,

32 THANK YOU!, Any Questions?