Continuous Asphalt Mixture Compaction Assessment using

Continuous Asphalt Mixture Compaction Assessment using Density Profiling System (DPS) [Pooled Fund: TPF 5(443)] (October 14, 2020) Shongtao Dai Office of Materials and Road Research Minnesota Department of Transportation Mn/DOT Office of Materials and Road Research

Technical Advisory Committee Financially Contributing Agencies: FHWA, Idaho, Maryland, Mississippi, Missouri, Maine, New York, Ohio, Pennsylvania, Washington, North Dakota, Utah, Minnesota, Wisconsin? Technically Contributing Agencies: (A lot of experience, knows issues and needs) Alaska; Florida and Nebraska (we can add as needed) Objective A) Further advance and improve DPS system B) Support communication C) Provide training and technical assistance to states and others D) Promote DPS to other vendors, contractors, consultants and DOTs and local government, etc. 2

Project Status Update Workplan developed around these objectives – March, 2020 Task 1: Software and Hardware Improvements Task 2: Development of AASHTO Data Collection and Analysis Specification Task 3: Precision and Bias Statement Task 4: Equipment and Operator Certification Task 5: Support Communication Task 6: Provide Training and Technical Assistance Task 7: Promote the technology 3

Task 1: Software and Hardware Improvements Developed a contract with GSSI: develop more user friendly software for the participates for easy implementation. The contract ends on March 31,2021 Task A – Compatibility Improvements. Task B – GPS Processing Improvements Task C – Data Management Improvements Task D – Data Calculation Improvements Task E – Precision and Accuracy Task F – Dielectric to Air Void Software Task G – Data Quality Assurance Module Task H – Core Validation Module Task I – Daily Analysis and Reporting CSV Files Task J – System failure indication 4

Task A – Compatibility Improvements Task B – GPS Processing Improvements Allow software to read input information from a file. Issue: In 1.0, GPS has an offset in the direction of travel which is affected by speed. Task C – Data Management Improvements Allow online transfer of field collected data in a user-friendly and timely manner -- Cloud 5

Task D – Data Calculation Improvements Issue: Underlying layer effect on dielectric calculation The issue should have been resolved in 2.0 – we will check. HMA PCC Task E – Precision and Accuracy HDPE block and puck with accuracy provided with 2.0 Roger is looking for another material with higher dielectric constant. 6

Task F – Dielectric to Air Void Software A stand-alone software (an additional icon) to allow user to input puck calibration data (dielectrics and density), perform regression and output calibration curve coefficients. Task G – Data Quality Assurance Allow user to check consistency of 3 sensors by performing swerving or transverse line testing. Assess the data: pass, correction or fail. Histogram 2000 Task H – Core Validation Module A part of 2.0 software to allow user to measure/store dielectric at core locations and core density test results Compare results with lab calibration. 1800 1600 1400 Frequency 1200 1000 36.5L 800 35L 600 33.5L 400 200 0 Bin 7

Task I – Daily Analysis and Reporting CSV Files Provide user flexibility to review and output data: histogram; joint vs mat. PaveScan 2.0 has improved features Task J – System Failure Indication During routine data collection, if the system fails (ex: a sensor suddenly gives very high or low value; or power outage; or sensor temperature is out of range, etc), the software should indicate the failure and record the time and date when the failure occurs to the data file. The failure should be documented in a stored file. 8

Task 2: Development of AASHTO Data Collection and Analysis Specification Drafted procedure of data collection and analysis for dielectric to AV% conversion using Gyratory Specimens. Drafted procedure of field data collection and analysis. Created training videos associated with these. http://www.dot.state.mn.us/materials/dps/index.html The website will be updated periodically to include any new information/materials Planning to replace the procedures and lab testing video with 2.0 by the end of Feb. 2021 and field testing video by May, 2021. 9

Continue data collection to build up database needed to the specification development. Data collection this summer: Th251, Th2, Th30, Th95, Th25 and MnROAD. Hired contractors for data collection Get feedback from contractors: how to develop specifications that are acceptable for contractors to use. Promoting the technology. 10

Challenges and Observations in data analysis: Example: Bias and sensor variation Need statistic analysis to better understand physical meaning from collected data and incorporate to the specifications. 11

Moisture measurement device Goal: a device that can go along with DPS system to continuously assess moisture on the pavement surface. Dr. David White from Ingios Demonstrated to us in Dec. 2019— promising Working on sensitivity Plan to invite him back for field testing FLIR MR160 Moisture Meter Mode: Image, contact and pin Good for core location: spot check 12

Task 3&4: Precision and Bias Statement & Equipment and Operator Certification Take Advantage of NCAT Test Track, New Construction, Laboratory and Expertise. NCAT manages one of the inertial profiling system certification centers. Promoting the technology to their sponsors. Please provide your comments on their proposal by Oct. 23. 13

Precision and Bias Statement In general, follow ASTM E691, “Standard Practice For Conducting an Interlaboratory Study To Determine The Precision Of A Test Method” Repeatability: Same test method on identical test items in the same laboratory by the same operator. Reproductively: Same test method on identical test items in different laboratories with different operators. Including (MnDOT will also provide data to NCAT) Lab Dielectric to AV% Conversion Produce pucks at 88%, 90%, 92% and 94% with fine and coarse mixtures and a HDPE specimen Round-robin testing among the participants Field Dielectric Data Collection At least 3 devices (9 sensors) will used New test sections (10-12) with fine and coarse mixtures and different thickness (1-3in) 14

Equipment and Operator Certification In general, follow AASHTO R 56‑14 “Standard Practice for Certification of Inertial Profiling Systems”. NCAT manages one of the inertial profiling system certification centers. Including Lab Dielectric to AV% Conversion Lab testing on pucks with different density (88%, 90%, 92% and 94%) Find out critical steps to get consistent and accurate results Field Dielectric Data Collection Existing 4 test sections with 4 different density levels (from 88% to 94% by Gmm) OGFC section will be used. Baseline density: unclear gauge testing at 1 ft interval on 4 lines (1 close to joint); cores will be taken on these locations later. Perform DPS testing on these lines MnDOT will also provide them data Operator Certification Develop online training and testing program. 15

Task 5: Support Communication Face to face in fall 2021 Webinar in spring 2021 to review the data collected by states Please send data to Kyle if you collected Revise the draft procedures by May 2021 Incorporate state and contractor’s comments/feedback Address issues identified from data analysis (ex. Puck vs core bias) Update procedures with 2.0 device 16

Task 6: Provide Training and Technical Assistance Have been providing online assistance and will continue to do so If needed, we can provide onsite training once we are allowed to travel. List of DOTs Contractors and 3rd party Ohio Grace Pacific (Hawaii DOT) Minnesota Jas Glover (Hawaii DOT) Maryland Advance Testing (NY DOT) Idaho Advance Engineering Testing, Minnesota (FHWA) North Dakota GenEx Systems, Virginia (FHWA) Utah is in process of purchasing. Trying for this month Wouri Technology Consulting, North Dakota (I believe self-funded) Missouri (not sure of this one yet) Mathy Construction, Wisconsin (I believe self-funded) NY. Applying for funding 17

Task Conference call with GSSI to discuss potential implementation 7: Promote the technology Looking at how they can better provide support to contractors in the future. Craig Landefeld from OHDOT made an excellent presentation at NRRA seminar Presentations at our biweekly bituminous meetings Collected data using Earth Science Pavement Density meter Promoted the technology to contractors Will make a brochure 18

Budget 19

Thank you! 20