WRI Research Related to the Optimal Timing of Preventive Maintenance for Addressing Environmental Aging

Transcription

1 WRI Research Related to the Optimal Timing of Preventive Maintenance for Addressing Environmental Aging Kickoff Meeting Fred Turner Western Research Institute MnROAD Research Facility July 23, 2008

2 Relevant Research Contracts Fundamental Properties of Asphalts and Modified Asphalts III, Federal Highway Administration Asphalt Surface Aging Prediction (ASAP) System, Research and Innovative Technology Administration Asphalt Research Consortium, Federal Highway Administration (Aging element, F1c, being conducted by TAMU) 2

3 FPIII Aging Research Study aging in laboratory and field conditions Develop testing methods for analyzing aging Compare results with the Global Aging System as implemented in the MEPDG 3

4 Techniques Developed Micro extraction with FTIR analysis Photoacoustic FTIR for surface analyses Small scale DSR methodology for full range modulus and relaxation rheology (in progress) Carbonyl index Non-carbonyl FTIR-G* correlations Spectral correlation software 4

5 Aging at the Arizona Validation Site 5

6 Arizona Validation Site Constructed Nov Shoulder cored Nov mm lifts, 19-mm NMS dense graded aggregate, 4.7% AC) Farrar, M. J., P. M. Harnsberger, K. P. Thomas, W. Wiser. Evaluation of Oxidation in Asphalt Pavement Test Sections after Four Years of Service. Proceedings of the International Conference on Perpetual Pavement, September, 2006, Columbus, Ohio. 6

7 1000 Asphalt Hardening: Laboratory and Field Aging Relationship between carbonyl content and complex modulus of asphalts gel G*, kpa, 60 C, 10 rad/s Carbonyl Content, Absorbance Units sol 80 C, Dry 60 C, Dry 80 C, Moist 60 C, Moist AZ1-1 7

8 Arizona Site Aging Profile Carbonyl Gradient AZ1-1 Carbonyl Index (A1700/A2900) Depth (mm) Linear relationship Log G* vs. C=O G* Gradient Hirsch Model E* Gradient 8

9 Infrared Spectra From Each Layer AZ1-3b core Spectra normalized to CH 3 umbrella bending mode at 1376 cm -1 Carbonyl index Sulfoxide index Aromaticity index Other indexes Functional group depth gradients 9

10 G* gradient - Arizona validation site at year four Calibration curve 10

11 Carbonyl Index Absorbance A 2900 Absorbance A Wavenumber, cm Wavenumber, cm -1 Carbonyl Index (CI) = A 1700 A

12 Carbonyl Index (8 asphalts) 12

13 ASAP Project Develop and demonstrate ruggedized FTIR instrumentation, data acquisition system, and data processing procedures to predict and monitor the surface embrittlement of asphalt pavements caused by aging 13

14 Techniques Applied Micro extraction with FTIR analysis Photoacoustic FTIR for surface analyses Carbonyl index Non-carbonyl FTIR-G* correlations 14

15 Project Elements Laboratory (WRI) Validate spectroscopy-rheology correlation Find non-carbonyl relationship for airborne applications Prepare samples for calibrating ruggedized FTIR system Unaged, RTFO-aged, RTFO/PAV-aged, field samples Develop procedures for handling real-world analyses: Asphalt content < 100%, Aggregate infrared absorption, contaminants Carbonyl indexing Aggregate and contaminant subtraction techniques 15

16 Project Elements Development of FTIR system (Innova, PLX, SimWright) Design, construct, and test a vehicle-mounted ruggedized FTIR system Demonstrate the technology in the field using a vanmounted, non-contact system Determine the effective limits for low-altitude airborne deployment 16

17 Age-Related Change at Surface Observations and Assumptions Az1-1 4-yr viscosity profile HMA pavements oxidize most rapidly at their top surfaces. The oxidized binder at the surface has a much higher stiffness than the bulk binder e+5 4e+5 6e+5 8e+5 The surface stiffness or complex modulus at lower ambient temperatures will approach the glassy modulus of the binder (~ 10 9 Pa). Depth, inches 2 3 Pavement damage begins under traffic load when the surface complex modulus of the binder reaches some fraction of the glassy modulus at current use temperature e+5 4e+5 6e+5 8e+5 Binder Viscosity, P 17

18 Infrared Spectra Changes w/ Aging WRI/FHWA AAB-1 neat AAB-1 RTFO Absorbance Carbonyl Solvent AAB-1 PAV 100 C 20hrs AAB-1 PAV 80 C 480hrs cm -1 Region Wave Number, cm -1 18

19 Infrared Spectra Changes w/ Depth Absorbance WRI/ FHWA Pavement Depth Surface 0.1" 0.5" 1" Wave Number, cm -1 19

20 G* Correlations With Carbonyl Content For AAB-1 1.E+08 1.E+07 AAB-1 y = 1.12E+06e 9.54E+00x R 2 = 9.24E-01 Shear Modulus, G*, at 10 rad/s 1.E+06 1.E+05 y = 2.88E+03e 1.63E+01x R 2 = 9.70E C unaged 25 C RTFO 25 C PAV at 60 C 1.E C PAV at 80 C 25 C PAV at C unaged 60 C RTFO 1.E C PAV at 60 C 60 C PAV at 80 C 60 C PAV at 100 C 1.E Carbonyl Content (1700 cm -1 ), au 20

21 Analysis of Infrared Spectra for Correlating Regions 1.0 AAM-1 R-Squared for Asphalt AAM-1 Correlation Log(G*) at 60 C, 10 Rad/s Wave Number

22 Comparison of Absorbances for Laboratory Sample AAM AAM IR Absorbance at 1212 cm y = x R 2 = IR Absorbance at 1703 cm -1 22

23 Relationship Between Absorbance at 1212 cm -1 and G* 6.0 AAM y = x R 2 = Log G* Absorbance at 1212cm-1 23

24 G* Correlation Using Absorbance at 1212 cm y = x R 2 = G*, fit Four asphalts, ten aging conditions G*, measured 60 C, 10rad/s 24

25 PA spectra changes on oxidation of AAD (a) Blue: Unaged. Green: RTFO only. Black: RTFO/PAV 20hours. Brown: RTFO/PAV 144 hours. Pink: RTFO/PAV 240 hours. Red: RTFO/PAV 480 hours. OPD velocity 0.5 cm/sec, 512 co-added scans, gain (4). 5.0 PA Intensity (arbitray units) cm-1 25

26 Photoacoustic spectra Arizona surface samples from AZ1-3b 512 co-added scans Small (approx. 4 mm wide) samples removed from the surface AZ1-3b core 26

27 PA Spectra of Aggregates 27

28 What is Needed? Validation sites for evaluating concepts and instrumentation Multiple asphalt sources and grades Multiple surface treatments Save original materials Periodic distress surveys and coring High-resolution age profiling in cores 28

29 WRI Contribution Age profiling in cores using micro extraction, photoacoustic techniques Field analyses with ASAP System Other specialized testing? 29

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31 G* Correlations With Carbonyl Content For AAC-1 1.E+08 AAC-1 1.E+07 Shear Modulus, G*, at 10 rad/s y = 4.42E+05e 7.92E+00x 1.E+06 R 2 = 9.62E-01 1.E+05 y = 6.65E+02e 1.14E+01x R 2 = 9.58E-01 1.E C unaged 25 C RTFO 1.E C PAV at 60 C 25 C PAV at 80 C 25 C PAV at 100 C 60 C unaged 60 C RTFO 60 C PAV at 60 C 1.E C PAV at 80 C 60 C PAV at 100 C Carbonyl Content (1700 cm -1 ), au 31

32 G* Correlations With Carbonyl Content For AAD-1 1.E+08 1.E+07 AAD-1 y = 4.22E+05e 1.69E+01x R 2 = 9.23E-01 Shear Modulus, G*, at 10 rad/s 1.E+06 y = 1.64E+03e 2.48E+01x R 2 = 9.74E-01 1.E C unaged 25 C RTFO 25 C PAV at 60 C 1.E C PAV at 80 C 25 C PAV at 100 C 60 C unaged 1.E C RTFO 60 C PAV at 60 C 60 C PAV at 80 C 60 C PAV at 100 C 1.E Carbonyl Content (1700 cm -1 ), au 32

33 G* Correlations With Carbonyl Content For AAM-1 1.E+08 1.E+07 AAM-1 y = 1.60E+06e 5.07E+00x R 2 = 9.46E-01 Shear Modulus, G*, at 10 rad/s 1.E+06 1.E+05 1.E+04 1.E+03 1.E+02 y = 3.92E+03e 1.02E+01x R 2 = 9.72E C unaged 25 C RTFO 25 C PAV at 60 C 25 C PAV at 80 C 25 C PAV at 100 C 60 C unaged 60 C RTFO 60 C PAV at 60 C 60 C PAV at 80 C 60 C PAV at 100 C Carbonyl Content (1700 cm -1 ), au 33

34 Wave Number, cm-1