DOTD LTRC. Quality Control /Quality Assurance (QA/QC) (QA/QC) Influence Widths and Depths. Density vs. Stiffness

Transcription

1 A presentation by What s the Problem? Gavin Gautreau, P.E. Louisiana Transportation Research Center (LTRC) Sr. Geotechnical Research Engineer Murad Abu-Farsakh, P.E., Ph.D. Louisiana Transportation Research Center (LTRC) Associate Professor, Research, Geotechnical Engineering Research Laboratory (GERL) Manager DOTD LTRC What s the problem? I don t think it was compacted properly Intelligent Compaction Technology LTRC Project Number: 06-3GT Quality Control /Quality Assurance (QA/QC) Contractor Quality Control (QC) Contractor experience Means and methods Roller compactors energy into layer Required to build uniform pavement layers Compaction and Density Moisture content control Obtain density of pavement layers Meet the specifications Quality Control /Quality Assurance (QA/QC) Departmental Quality Assurance (QA) Acceptance Testing Departmental Nuclear Moisture Density Testing Roughly 1 test per 1000 feet of road What do we know about the points in between? Consistency vs. Irregularities? Density vs. Stiffness Influence Widths and Depths Density Mass/Volume Proctor Tests, Nuclear Gauge, Sand Cone, etc. Optimum moisture (soils) / temperature (HMA) Compactive effort energy Stiffness Deflection under Load Dynamic Cone Penetrometer, Falling Weight Deflectometer, LFWD, GeoGauge, etc. M E Pavement Design Guide Methodology NCHRP Report 676 1

2 GPS Technology and Precision Continuously Operating Reference Stations (CORS) Recent LTRC Projects 07-3GT Corps of Engineers 07-4GT Public Works 09-2GT Pavement Management 09-3GT Corps of Engineers 10-1GT Public Works 11-6GT HQ Public Safety mation/gps%20correction%20services%20for%20alabama.pdf Automated Machine Guidance (AMG) Automated Machine Guidance GPS Receivers AMG links sophisticated software with construction equipment to direct the operation of machinery with a high level of precision, improving the speed and accuracy of highway construction processes. Commonly used for grade control Motor Graders, Dozers, etc. Road construction, levee construction, etc. Intelligent Compaction Intelligent Soil Compaction Systems The combined use of an Instrumented Roller and Automatic Feedback Control in an attempt to improve earthwork compaction. Specific term, yet generically used as a common reference to the technology. 2

3 (NCHRP) Report 676: Intelligent Soil Compaction Systems The report explores intelligent compaction, a new method of achieving and documenting compaction requirements. Intelligent compaction uses continuous compaction-roller vibration monitoring to assess mechanistic soil properties, continuous modification/adaptation of roller vibration amplitude and frequency to ensure optimum compaction, and full-time monitoring by an integrated global positioning system to provide a complete GPS-based record of the compacted area. FHWA Every Day Counts - Initiative introducing new technologies Intelligent Compaction / Continuous Compaction Control Automated Machine Guidance Roller Integrated Compaction Monitoring (RICM) Roller Integrated Compaction Monitoring (RICM) [i.e., intelligent compaction (lc) or continuous compaction control (CCC)] refers to the compaction of road materials, including subgrade soils, aggregate bases, stabilized materials, and asphalt paving materials, using modern rollers equipped with an integrated IC or CCC measuring system. Continuously records the roller s location and reaction to layer stiffness and plots the result during compaction operations, so the operator can adjust to ensure appropriate compaction effort. The recorded stiffness measurements can be correlated to conventional physical and engineering properties of materials, such as dry density, strength, and modulus. The field generated data and plots also provide a good means for quality control/quality assurance (QC/QA) of compaction operations. Influence Areas and Depths Sample Coverage NCHRP Report 676 Roller Operator questions Roller Parts with GPS Roller Passes How many for density? How many were made? Were that many passes needed? Did every part of the project Get touched/compacted by the roller? Get the required number of passes? 1. Roller (example) 2. Global Positioning System (GPS) 3. Onboard Display What if we add a GPS and technology to a Roller that is already on the job? 3

4 GPS Precisions Coverage Record Pass Counts Continuous Compaction Control 1 st Pass 2 nd Pass: 3 rd Pass (or target # of passes) Records location (X,Y) and number of passes on soils or asphalt. Colors guide the operator GPS Precision affects display of paths Emerging Technology Common in Europe GPS devices determine location Data collection Time, Project, Job #, etc. Position (X, Y) Pass Control Elevation (Z) Layer Data Stiffness Measurements Qualitative measurements of the entire job GPS coordinates allow mapping to GIS Measurement Systems Smart Roller Parts CCC Accelerometer-based Force vs. Displacement (E vib, k s ) Drum mounted accelerometer and position sensors Signals can be used to control drum amplitude and frequency Compaction Meter Value (CMV & CCV) Drum mounted accelerometer measures ground reaction Signals can be used to control drum amplitude Energy Method: Machine Drive Power (MDP) Measures driveline power used to overcome rolling resistance with corrections made for grade and machine acceleration Works on both vibratory and non vibratory compactors Works on cohesive soils Instrumented Roller: A roller compactor outfitted with drum vibration instrumentation or other means to compute a Roller Measurement Value, onboard computer, and position monitoring equipment. 1. Roller (example) 2. Engine/Hydraulics 3. Vibratory Settings 4. Soil (or HMA) Reaction 5. Accelerometers 6. Global Positioning System (GPS) 7. Onboard Display /Storage Computer 8. Temperature sensors (Double Drum, HMA) 4

5 Compaction Measurements Compaction Measurements Roller Measurement Values Roller Integrated Stiffness (k s ) Ammann/Case Compaction Meter Value (CMV) CAT/Dynapac Compaction Control Value (CCV) Sakai Ω = excitation frequency C = constant (usually 300) A 2Ω = 2 nd harmonic of vertical drum acceleration frequency domain amplitude A Ω = 1 st harmonic of vertical drum acceleration frequency domain amplitude Ω = excitation frequency A 2Ω = 2 nd harmonic of vertical drum acceleration frequency domain amplitude A Ω = 1 st harmonic of vertical drum acceleration frequency domain amplitude 5

6 Vibration Modulus (E VIB ) Bomag De Coupled Layer Moduli Bomag Contact Force, kn Drum Displacement, mm Equivalent Deformation modulus Layer deformation modulus E 1 Contact Contact Force, kn Force, [kn] E 2 The E vib meter enables the determination of a measuring magnitude directly related with the deformation modulus EV of the soil during each vibration movement and on the basis of the interrelationship between force and immersion of the roller into the ground. Drum Displacement, mm Contact Contact Force, kn Force, [kn] E vib measuring depth effect E 1 = Layer modulus of compacted layer E 0 = Subgrade modulus Drum Displacement, mm Automatic Feedback Machine Drive Power (MDP) 1. Roller Vibration off 2. Cohesive Soil 3. Drive Energy 4. Reactions: Softer soils require more energy to move vs. hard and smooth 5. Onboard Display / Data Computer Automatic adjustment of roller operating parameters such as vibration frequency and amplitude based on real-time feedback from measurement system. P g = gross power of roller W = roller weight a = machine acceleration g = gravity θ = slope angle (roller pitch) V= roller velocity m, b = machine loss coefficients (machine specific) Stiffness/MV with Pass < Target Stiffness/MV Near Target Stiffness/MV Meets Target Stiffness/MV Helps speed contractor efforts Records stiffness for entire area Identifies problem areas - too wet, pipe, etc. Moisture (soils) and temperature (HMA) still need to be good for compaction. The roller wont change these properties. Soil IC Rollers Vendor Model Model # Auto ICMV Feedback ICMV Unit Document System Main US Contact Ammann/Case ACEplus SV Yes k s MN/m ACE Plus George Whitaker (262) George.whitaker@cnh.com Bomag VarioControl BW213 4BVC Caterpillar Compaction Control, AccuGrade CS44 CS78 CP54 CP74 Yes E vib MN/m 2 BCM o5 Office and Mobile No CMV MDP Unitless AccuGrade VisionLink Chris Connolly (301) Chris.Connolly@bomag.com Todd Mansell (763) Mansell_Todd_W@cat.com Dynapac DCA S(GPS) CA Yes CMV Unitless DCA Gert Hannson (210) Gert.hansson@dynapac.com Sakai CIS SW850 SW900 No CCV Unitless AithonMT S Brandon Crockett (800) B crockett@sakaiamerica.com HAMM/Wirtgen HCQ NA No HMV Unitless HAMM HCQ Tim Kowalski (615) tkowalski@wirtgenamerica.com Volvo Trimble NA No CMV Unitless Trimble Bob Marcum SiteVision (828) Bob.Marcum@volvo.com IntelligentCompaction.com 6

7 Asphalt IC Rollers VEDA, Geospatial Analysis Software for Intelligent Compaction and Sonic Testing Rolling Vendor Model Model # Auto Feedback Bomag Asphalt Manager ICMV ICMV Unit Docume nt System BW190AD 4AM Yes E vib MN/m 2 BCM o5 Office and Mobile Main US Contact Chris Connolly (301) Chris.Connolly@bomag.com Sakai CIS SW850 SW900 No CCV Unitless AithonMT Brandon Crockett (800) B crockett@sakaiamerica.com HAMM/ HCQ HD+90/ HD+110 No HMV and Unitless HAMM Tim Kowalski Wirtgen HD+120/ HD+140 estimated and % HCQ (615) densities compaction tkowalski@wirtgenamerica.com IntelligentCompaction.com Objectives, LTRC Research 06 3GT New Iberia Frontage Roads, H US 90 (Darnall to LA 85) Demonstrate the value of real time quality control of compaction operations to accelerate construction, reduce re work, and improve uniformity. Improve value of field data and reduce frequency of traditional required sampling through improved construction process control. Evaluate the reliability and potential use of IC data for acceptance and measurements of in situ stiffness of the constructed earth and asphalt materials; linking to properties that relate more directly to design (e.g. modulus) and in service performance. LTRC Demo Project, 06 3GT Shadowing the normal acceptance process. Existing Frontage Roads will be connected as part of the future I-49 corridor. 1) 1.5 Superpave Asphaltic Concrete Wearing Course (Level 1) 2) 2.0 Superpave Asphaltic Concrete Binder Course (Level 1) 3) 8.5 Class II Base Course (Soil Cement) 4) Pavement Striping 5) Pavement Striping & Reflectorized Markers 6) 12 Treated Subgrade Layer 7

8 Zone Information Mapping Applications Machine Drive Power (MDP) Compaction Values Coverage Elevation Weather Delays Pass Count Summary Was Target # Passes Met 8

9 Pass Counting Asphalt CCV with pass Sakai roller data imported into VEDA Software CCV values increase (darken) with each pass. Existing frontage road asphalt removed. existing vs new, treated subgrade Asphalt Temperature with Pass Sakai roller data imported into VEDA Temperature record (lighter) with each pass. Next Steps Continue the Test Sections Collect and Analyze Data Re evaluate Specification Final Report Benefits of Roller Integrated Compaction Monitoring Single Drum IC Rollers Contractor: On board Roller Display Consistent coverage and Pass tracking Verification of compaction effort (Measurement Values) Identifies weak areas Faster compaction (stiffness vs. arbitrary passes) LADOTD Increases sample coverage vs. point tests Records continuous compaction efforts Speeds construction (appropriate passes/energy) Possible replacement for the nuclear gauge (research) Promotes consistent and uniform pavement layers 9

10 Double Drum IC Rollers Benefits of Intelligent Compaction Improve Compaction & Consistency Better Performance Improve Efficiency Cost Savings Increase Information Better QA/QC Acknowledgements National Cooperative Highway Research Program (NCHRP) Report 676: Intelligent Soil Compaction Systems Dr. David White, Iowa State University Sid Scott, SHRP2 Transtec Group & IntelligentCompaction.com District 03, Mark Arceneaux, et. al. Gilchrist Construction, Caterpillar, Sakai, Spectra Measuring LTRC Staff (Geotechnical, Pavement, Asphalt, GERL) Thanks! 10