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Pavement Management System

FAA-ERDC Interagency Agreement Research Update Dr. Alessandra Bianchini, PE FAA Working Group Meeting 24-26 April, 2012. Pavement Management System. US Army Corps of Engineers BUILDING STRONG ®. FAA – ERDC Interagency Agreement. Three Projects

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Pavement Management System

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  1. FAA-ERDC Interagency Agreement Research Update Dr. Alessandra Bianchini, PE FAA Working Group Meeting 24-26 April, 2012 Pavement Management System US Army Corps of Engineers BUILDING STRONG®

  2. FAA – ERDC Interagency Agreement • Three Projects • Performance Tests for Superpave HMA Mix Design • Assessment of Material Strength Using Dynamic Cone Penetrometer (DCP) and Vane Shear Tester (VST) • Field Evaluation of Rigid Pavement Curling and Residual Stresses

  3. Performance Tests for Superpave HMA Mix Design P.I. John Rushing (John.F.Rushing@usace.army.mil) Pavement Management System US Army Corps of Engineers BUILDING STRONG®

  4. Performance Tests for HMA Designed Using Superpave Gyratory Compactor • OBJECTIVE • Develop recommendations for HMA performance tests to accompany Item P-401 Superpave mix design procedure • TASKS • Evaluate common HMA performance tests • Determine test precision • Determine relationship to prediction models

  5. Laboratory Performance Tests • Asphalt Pavement Analyzer (APA) – accelerated wheel tracking • Confined Repeated Load – uniaxial confined compression test (Flow Number) • Confined Static Creep – uniaxial confined creep test (Flow Time) • Dynamic Modulus – uniaxial compression using temperature and frequency sweep

  6. AsphaltPavementAnalyzer Temperature = 64C, Hose pressure 250 psi gravel 30% sand granite Limestone – no sand -- Paper on APA testing accepted for publication in the Transportation Research Record (2012) --

  7. FlowNumber • Repeated load tri-axial test (40 psi confining stress, 200 psi axial stress) • Flow number defined as number of load repetitions corresponding to the start of shear deformation under constant volume 30% sand Limestone – no sand

  8. FlowTime • Static creep tri-axial test (40 psi confining stress, 200 psi axial stress) • Flow time defined as time (under constant loading) corresponding to the start of shear deformation under constant volume 30% sand Limestone – no sand

  9. Dynamic Modulus • Frequency: 25, 10, 5, 1, 0.5, 0.1 Hz • Temperature: 70, 100, 130F • Low temperatures (14, 40oF) excluded for rutting evaluation • Testing according to AASHTO TP 62-07 Limestone – no sand 30% sand

  10. Summary • Several promising tests considered as potential performance test to supplement P-401mix design • Majority of laboratory testing complete • Currently analyzing performance test data • Recommendation for new test and specifications to be included in final report in late 2012

  11. Assessment of Material Strength Using DCP and VST • P.I.s Lulu Edwards • (Lulu.Edwards@usace.army.mil) • Lyan Garcia • (Lyan.Garcia@usace.army.mil) Pavement Management System US Army Corps of Engineers BUILDING STRONG®

  12. Assessment of Material Strength Using DCP and VST • OBJECTIVE • Guidance for implementing DCP in assessment of unbound (granular) pavement materials • PROJECT PLAN • Comparison of DCP and VST for construction control • Analysis of DCP for • estimating backcalculated stiffness values • checking anomalies in HWD results • confirmation of as-built layer thicknesses • developing sub-layering profiles

  13. Project Status • Side by side testing of the DCP and HWDto evaluate anomalous HWD results • @ 3 airfields: Phillips, Butts, and Lawson Army Airfield • Findings: DCP allows verifying layer thicknesses and detecting variability within a segment of a runway or taxiway. • DCP database under development • DCP data and corresponding material and physical properties • Test sections and full-scale field tests • Airfield Evaluations • Data from 15 airfield evaluations and 2 projects conducted at the ERDC are included in database so far • Data from other test sections are currently being gathered

  14. Database • Database was generated to keep track of all data collected from various testing/evaluations • Database has all of the data desired, but not all fields will be populated, depending on the testing/evaluation • Data will be extrapolated from the database in order to develop correlations • Data is entered in by DCP test • Supplemental information or other testing results performed at the same location are included

  15. Database • Data entry form: • Layer materials and thicknesses • CBR test results (lab and on-site) • CBR manually picked from DCP

  16. FWD/HWD and Modulus Data • Resilient modulus • FWD/HWD data • Backcalculated modulus values • Backcalculation method Material Physical Properties • Plasticity index • Dry density • Nuclear gauge • Sand cone • Moisture content • Nuclear gauge • Oven • Optimum moisture content • Proctor • Modified Proctor

  17. Database: Shear Strength • Shear strength values measured with • Vane shear • Triaxial test • Direct Shear test

  18. Future Work • Correlation of backcalculatedmoduli to DCP penetration rate using airfield and test section data • Comparison with correlations in the published literature • Comparison of the percent change of layer thicknesses to the percent change of penetration rate at the same depth • Data separated by soil type • Evaluation of DCP and VST for construction control using test section data • Note: most test sections have a high-plasticity clay (CH) subgrade • Unsurfaced runway data available for analysis, if needed • In-situ CBR, moisture content, density were collected along with DCP data • Only some vane shear data available

  19. Field Evaluation of Rigid Pavement Curling and Residual Stresses • P.I. Alessandra Bianchini • (Alessandra.Bianchini@usace.army.mil) Pavement Management System US Army Corps of Engineers BUILDING STRONG®

  20. Field evaluation of rigid pavements curling • OBJECTIVE • Establish correlation between HWD deflections, slab thickness, and temperature deformation; • Evaluate core-ring and saw-cut testing methods to quantify residual stresses • PROJECT PLAN • Identify DoD bases with rigid pavement thickness 12 -16in. • Phase I: HWD testing during end-of-summer months when maximum slab downward curling • Phase II: HWD, core-ring and saw-cut surface testing during winter months when maximum slab upward curling and tensile surface stresses

  21. Selected Testing Sites • Laughlin AFB, TX – 1 apron; thickness 12.25 in. • Robert Gray AAF, TX – 3 aprons; thicknesses 13, 14, and 14.5 in. • Dyess AFB, TX – 2 aprons; thicknesses 15 and 16 in. • 6 slabs for each apron were dedicated to testing Dyess AFB Laughlin AFB Robert Gray AAF

  22. Field evaluation of rigid pavements curling 3 4 2 5 1 6 • Phase I (HWD testing) • Main objective: correlate temperature to deflection at the corner as indicator of slab curling • HWD Testing: on each apron 2 testing sessions • early morning (cooler temperatures) • late afternoon (higher temperatures) • An ANOVA confirmed the influence of thickness in the measured deflections • Regression analysis: the ISMratiovs Temperature. ISM average values at the slab corners, joints, and center and surface temperature values. • Regression analysis: normalized SD differences and surface temperature differences between afternoon and morning testing sessions. Test locations

  23. Field evaluation of residual stress tests • Phase II (Test field evaluation) • Main objective: evaluate testing methods to measure residual stresses • @ each base • HWD Testing • Saw-cut and Core-ring testing on the slab centers (for every apron: 3 slabs/type of test) • Site visited: Laughlin AFB, Robert Gray AAF, Dyess AFB

  24. FAA Residual Stresses – Test Methods Saw cut line Gage 1 Gage inclined at 45 deg Core-ring cut 1 in. 1 in. 1 in. 1 in. Gage 2 Gage 3 • Core-Ring Method • ½ in strain gages • 4in. Ring diameter;1.25 in. cut depth • external gages connected to data logger during the cut • 45 min recording time after cut completion • Sawcut Method • ½ in. strain gages • 4x4in. Sawcut square;1.25 in. cut depth • gages connected to data logger during the cut • 45 min recording time after completion of 4 cuts

  25. Core-Ring Method: Examples Gage 1 Core-ring cut 1 in. 1 in. Gage 2 Gage 3 Laughlin AFB – Apron A26B – 12.25 in. 105.92 10.8 -19.94 -36.25 -533.68 -81.34

  26. Core-Ring Method Gage 1 Core-ring cut 1 in. 1 in. Gage 2 Gage 3 Issue during test execution: Partial Coring Robert Gray AAF Apron A03B – 13 in. Dyess AFB Apron A11B – 15 in. • Partial coring (independent of the concrete age) • Wear of the core bit • Impossibility of using water (due to gage arrangement) • Gage instability (frequent) • Interpretation of the strain results • Difficulty in representing the stress field • Stress computation and interpretation

  27. Saw-Cut Method: Examples Saw cut line Gage inclined at 45 deg 1 in. 1 in. Laughlin AFB -12.25 in. -37.51 -43.04 -48.46 -22.10 -23.55 -29.52 Robert Gray AAF-13 in.

  28. Saw-Cut Method Strain gage rosette: computation of principal stresses E = 4,000,000 psi; v = 0.18 εy • 7 out of 20 tests were rejected based on the computed stress value that was greater than the typical concrete flexural strength (set at 500 psi) εxy A26B: t = 12.25 in. ANOVA confirmed influence of slab characteristics (thickness, age). Environmental conditions (wind speed, temperature differential, surface temperature) were not statistical significant on computed stresses. εx A06B: t = 16 in. A11B: t = 15 in.. A03B: t = 13 in. A06B: t = 14.5 in. A09B: t = 14 in.

  29. Advantages of the Saw-Cut Test • Easier to execute in the field • Test repeatability • Less frequent gage instability (than core-ring test) • Allows computation of principal stresses • Recommendations for future research • Evaluate concrete heating during the cuts • Evaluate/improve cut sequence • Specific analysis on the saw blade wear • Couple the test with computational tools/analysis • Development of criteria to accept/reject test data

  30. Questions? Pavement Management System US Army Corps of Engineers BUILDING STRONG®

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