NCAT/MnROAD Cracking Group Update. March 29, 2018

Transcription

1 NCAT/MnROAD Cracking Group Update March 29, 2018

2 Outline Project background Laboratory testing Pavement response Performance observations 2

3 Cracking Group Experiment Primary objective Correlate lab cracking tests to field performance Constraints Short timeframe Range of expected cracking Suite of lab cracking tests being performed by MnDOT and NCAT Identify the test(s) that best correlate with each type of field cracking 3

4 HMA Mixtures Mixtures selected to achieve range of low-temperature cracking (LTC) potential Based on input from pooled-fund sponsor states Contractor selected, procured materials, submitted to NCAT NCAT performed mix designs Contractor produced/placed mixture 4

5 Pavement Design Inputs WB I-94 average daily traffic volume ~30,000 vehicles ~13% HC Flexible ESALs ~800k per year (design lane) ètraffic level 5 Soils: USDA Clay Loam, Loam AASHTO A-6 USCS Lean Clay (CL) Expected life ~10 yrs 5

6 MnROAD CG Construction Contract Construction of 8 mainline I-94 HMA test sections ~$1.2 million construction contract Project let Friday, May 20, 2016 è four bidders Construction schedule - Contract: July 11 thru October 15, 2016 Actual: July 18 thru October 14, 2016 Opened to Traffic - November 2,

7 MnROAD CG Section Traffic Open to traffic - November 2, 2016 MnROAD 2017 NRRA construction No traffic from June 5 thru September 19, 2017 Approximately 900,000 ESALs to date 7

8 MnROAD Site MnROAD Mainline MnROAD Low Volume Road MnROAD Low Volume Road Cracking Group Cells

9 MnROAD Cracking Group Cells 9

10 Constructed Section Typical 10

11 Typical sensor layout Cells 17, 19, 21 11

12 Sensor layout Cell 23 12

13 MnROAD Mixtures Cell # NMAS Design RAP (%) Design RAS (%) QC Total ABR % Virgin Binder Grade QC Binder Content (%) Ndesign C16 (20% RAP/5% RAS) % 5% 42% 64S C17 (10% RAP/5% RAS) % 5% 28% 64S C18 (20% RAP/PG 64S) % 0% 24% 64S C19 (Cell 18 w/ +binder) % 0% 22% 64S C20 (30% RAP/52S-34) % 0% 37% 52S C21 (20% RAP/58H-34) % 0% 24% 58H C22 (Cell 21 w/ LMS) % 0% 23% 58H C23 (15% RAP/ HiMA) % 0% 18% 64E

14 Density Acceptance Nuclear density gage approach Avoid coring within cell Density cores within transition area Adjust gage readings using core bulk densities 14

15 Adjusted HMA nuclear density DRIVING PASSING CELL Lift 1 Lift 2 Lift 1 Lift

16 All cells showed significantly higher density within mat as compared to confined and unconfined joints RDM can get as close as 6 inches from joints Relationship is unique, dielectric affected by aggregate type: Granite ~5 Limestone ~7

17 Air Voids vs. Dielectric y = e x R² = 0.78 y = e -1.19x R² =

18 Cell 19 Dielectric/Density Results 18

19 Cell 16 Dielectric/Density Results 19

20 140 IRI (in/mi) / PASSING LANE (HiMA) 22 (LMS) 21 (Typ. MnDOT mix) 20 (30% RAP) 19 (3% AV) 18 (20% RAP) 17 (10% RAP, 5% MWSS) 16 (20% RAP, 5% MWSS)

21 140 IRI (in/mi) / DRIVING LANE (HiMA) 22 (LMS) 21 (Typ. MnDOT mix) 20 (30% RAP) 19 (3% AV) 18 (20% RAP) 17 (10% RAP, 5% MWSS) 16 (20% RAP, 5% MWSS)

22 NCAT/MnDOT Materials Testing Overview of mixtures Cantabro Tensile Strength Ratio (TSR) Hamburg Wheel Tracking Test (HWTT) 50 C and 45 C Illinois Flexibility Index Test (IFIT) IDT Creep & Strength (AASHTO T322) DCT Extracted binder properties 22

23 MnROAD Mixtures Cell # NMAS Design RAP (%) Design RAS (%) QC Total ABR % Virgin Binder Grade QC Binder Content (%) Ndesign C16 (20% RAP/5% RAS) % 5% 42% 64S C17 (10% RAP/5% RAS) % 5% 28% 64S C18 (20% RAP/PG 64S) % 0% 24% 64S C19 (Cell 18 w/ +binder) % 0% 22% 64S C20 (30% RAP/52S-34) % 0% 37% 52S C21 (20% RAP/58H-34) % 0% 24% 58H C22 (Cell 21 w/ LMS) % 0% 23% 58H C23 (15% RAP/ HiMA) % 0% 18% 64E

24 Cantabro Mass Loss, % C16 C17 C18 C19 C20 C21 C22 C23

25 Design Tensile Strengths Tensile Strength, psi C16 C17 C18 / C19 C20 C21 C22 C23 Unconditioned Conditioned

26 QC Tensile Strengths (PMLC) Tensile Strength, psi C16 C17 C18 C19 C20 C21 C22 C23 Unconditioned Conditioned

27 Tensile Strength Variation Cell Unconditioned Conditioned Difference, psi Difference, % Difference, psi Difference, % C % % C % % C18 / C % % C % % C % 5.7 6% C % -7-9% C % 8.6 9%

28 Tensile Strength Ratio (TSR) TSR C16 C17 C18 / C19 C20 C21 C22 C23 Design TSR PMLC TSR

29 Hamburg Wheel Tracking Test (HWTT) 50 C water bath, typical Rut depths were not recorded past 12.5 mm. All testing was done at 50 C. Lower temp for softer binder grades 158 lb. load Cyclic testing 10,000 cycles (20,000 passes) 2 sets per mix typical Specimen V a = 7.0 ± 0.5% Failure = 12.5 mm rutting

30 Hamburg Wheel Tracking Test (HWTT) Rut depths were not recorded past 12.5 mm. All testing was done at 50 C.

31 Hamburg Wheel Tracking Test (HWTT) Rut depths were not recorded past 12.5 mm. All testing was done at 50 C SIP = 7500 Passes SIP = 9500 Passes Rut Depth, mm C16 C17 C18 C19 C20 C21 C22 C23 Avg. Rut 10,000 passes (mm) Avg. Rut 20,000 passes (mm)

32 Hamburg Wheel Tracking Test (HWTT) Rut depths were not recorded past 12.5 mm. All testing was done at 50 C. Testing 45 C. Testing conducted at 45 C.

33 Illinois Flexibility Index Test (IFIT) 25 C 50 mm/min load rate Minimum of 6 replicates 50 mm thick specimens Notch Depth = 15 mm Notch Width = 1.5 mm Load vs. Axial Deformation Test until load < 0.1 kn Outlier evaluation 33

34 Illinois Flexibility Index Test (IFIT) FI = 0.01 G ) m

35 Illinois Flexibility Index Test (IFIT) Rut depths were not recorded past 12.5 mm. All testing was done at 50 C. Flexibility Index C16 C17 C18 C19 C20 C21 C22 C23

36 Cell ID IFIT Statistical Differences Flexibility Index Standard Deviation CV (%) Statistical Group Anticipated Cracking Potential C23 (15% RAP/ HiMA) A Low C20 (30% RAP/52S-34) A B C Moderate/High C21 (20% RAP/58H-34) A B Moderate C17 (10% RAP/5% RAS) A B High C18 (20% RAP/PG 64S) B C Moderate C22 (Cell 21 w/ LMS) B High C19 (Cell 18 w/ +binder) B C Moderate C16 (20% RAP/5% RAS) C High

37 Indirect Tension Test (IDT) AASHTO T Specimens are cut from SGC cylinders (38 50 mm thick) Creep compliance at 0 C -10 C, and -20 C (constant load is applied for 100 sec) and tensile strength at -10 C Temperatures vary by material Thermal stress analysis conducted to determine critical temperature

38 AASHTO T 322 IDT CC&S Rut depths were not recorded past 12.5 mm. All testing was done at 50 C. Testing 45 C. Testing conducted at 45 C.

39 Summary All cells had <10% ML from Cantabro testing Only Cell 22 plant mix failed TSR significantly Cells & 23 passed 50 C Cells with softer binder grades performed 45 C in Hamburg IFIT results generally followed expected trends Cells with 64S-22 binders among the 5 worst HiMA and lower binder grades top 3 39

40 Remaining Work TX Overlay Test (8 cells) Bending Beam Fatigue (8 cells) Note: recently completed but not reviewed Dynamic Modulus (FHWA) Small Specimen E* (TBD) 40

41 1200 MnDOT DCT FE 1000 FRACTURE ENERGY, J/M^ TEST SECTION LMLC Ave PMLC Ave THRESHOLD

42 CELL DCT Fracture Energy / PMLC DCT Testing Results (PMLC) N MEAN FE (J/m 2 ) CV (%) C23 (15% RAP/ HiMA) A C21 (20% RAP/58H-34) A B STATISTICAL GROUP C20 (30% RAP/52S-34) B C C16 (20% RAP/5% RAS) C D C19 (Cell 18 w/ +binder) C D C17 (10% RAP/5% RAS) D C18 (20% RAP/PG 64S) D C22 (Cell 21 w/ LMS) E Games-Howell method (95% confidence) Outliers removed (ASTM E178) 42

43 Binder Testing Results VIRGIN BINDER EXTRACTED (PAV) CELL RAP RAS SPEC PG CONT. PG CONT. PG Delta T c 16 64S S S S S NA 21 58H H E

44 MnROAD Dynamic Data Processing

45 Dynamic Data Processing Goals Provide common platform between sites User-friendly Visual quality checks Rapidly build databases

46 DADiSP Data Processing MnROAD Truck

47 Access Databases

48 Pavement Response Data Sensor testing with: Dynatest FWD MnROAD truck Data processing Results to date 48

49 MnROAD Truck 17.1k 16.8k 16.5k 17.7k 11.7k 49

50 AVERAGE PEAK STRAINS and HMA MID-DEPTH TEMPERATURE mph AVERAGE MICRO-STRAIN MID-DEPTH (F) C17 [64S-22, 28% ABR] C19 [64S-22, 22% ABR] C21 [58H-34, 24% ABR] C23 [64E-34, 18% ABR]

51 AVERAGE PEAK STRAINS and HMA MID-DEPTH TEMPERATURE mph AVERAGE MICRO-STRAIN MID-DEPTH (F) C17 [64S-22, 28% ABR] C19 [64S-22, 22% ABR] C21 [58H-34, 24% ABR] C23 [64E-34, 18% ABR]

52 MINIMUM AIR TEMPERATURES / Oct-2016 through Mar MINIMUM AIR TEMPERATURE ( C) /18/2016, /31/2017,

53 Cumulative FI, DegC-days Low-Temperature Cracking Min Air Temp, C

54 Cell 23 longitudinal edge line

55 Cell 19 passing lane

56

57 Cell 18 passing lane

58

59 Summary Performance testing is nearly complete BBF recently completed No clear distinguishing performance observations to date Pavement sensor responses follow anticipated trends with respect to speed and temperature Magnitudes also reflect anticipated mixture stiffness results

60 Summary, cont. Some cracking has appeared Consult available construction information RDM, FWD, IC, IR, GPR, etc. Non-destructive forensics FWD, GPR, as examples Destructive forensics Coring Decision made as to whether these will spread Pre-emptive measures?

61 Acknowledgements Pooled fund sponsor states Hardrives, Inc. Ingevity (anti-strip additive) WSB and Associates, Inc. MnDOT: District 3 ORS MnROAD staff OMRR staff NCAT Kyle Hoegh, Dave Timm, and Hyung Jun Ahn (all PhD) 61

62 Thank you! 62