Nondestructive Testing to Identify Delaminations Between HMA Layers: Phase III–Develop User Guidelines (2014) / Chapter Skim
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SHRP 2 Renewal Project R06D Nondestructive Testing to Identify Delaminations Between HMA Layers Phase 3 -- Develop User Guidelines
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SHRP 2 Renewal Project R06D Nondestructive Testing to Identify Delaminations Between HMA Layers Phase 3 -- Develop User Guidelines Michael Heitzman and Nam H Tran National Center for Asphalt Technology at Auburn University Auburn, Alabama Kenneth Maser Infrasense, Inc.
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© 2015 National Academy of Sciences. All rights reserved.
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NOTICE The project that is the subject of this document was a part of the second Strategic Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The Transportation Research Board of the National Academies, the National Research Council, and the sponsors of the second Strategic Highway Research Program do not endorse products or manufacturers.
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The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters.
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Contents 1 CHAPTER 1 Background 3 Phase 3 Objective and Work Plan 4 CHAPTER 2 Developing User Guidelines 4 Proposed Specifications 7 Survey of Vendors 8 Identify Target Users 8 Guideline Format 10 CHAPTER 3 Pilot Workshops 11 Workshop Discussion 13 CHAPTER 4 Summary and Conclusions 14 Reference 15 Abbreviations, Acronyms, Initialisms, and Symbols A1 APPENDIX A1 GPR Vendor Survey Responses A8 APPENDIX A2 SASW/IE Vendor Survey Responses B1 APPENDIX B1 GPR User Guidelines B22 APPENDIX B2 GPR Vendors' Features C1 APPENDIX C1 SASW/IE User Guidelines C17 APPENDIX C2 SASW/IE Vendor Features
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CHAPTER 1 Background Several types of surface distress in asphalt pavements, such as longitudinal cracking in the wheel path and tearing in the surface, can be attributed to delamination between hot mix asphalt (HMA) layers.
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and on ten 25-ft intact and delaminated pavement sections constructed on the NCAT Pavement Test Track. The evaluation was performed under warm-dry pavement and cool-wet pavement conditions.
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will require a lane closure and can be used to supplement GPR results. In addition, continuing improvement in data analysis software is needed to make NDT a network-level tool for detecting delamination in HMA pavements.
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CHAPTER 2 Developing User Guidelines The research team developed guidelines for using the NDT technologies improved under SHRP 2 Project R06D to identify delamination between asphalt layers. The guidelines were developed in three steps.
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Table 2.1 Proposed System Requirements for GPR System Component Specification System type Array of multiple antenna elements lined up transverse to the direction of travel Frequency Range - Impulse radar systems Center frequency of pulse > 2.0 GHz; –10 db limits: 0.5 to 5.0 GHz Frequency Range - Frequency sweep radar systems Frequency range: up to 3.0 GHz Lateral spacing of antenna elements < 1.5 ft Lateral coverage per pass 12 ft (full lane width) Longitudinal data collection rate > 2 scans per foot per antenna element Travel speed during data collection > 20 mph Travel speed during mobilization Posted speed limit Real-time display B-scan for selected antenna elements System monitoring and control From within the survey vehicle Data collection rate Data collection should be triggered on distance using a DMI Spatial reference Vehicle DMI, external distance wheel, or global positioning system (GPS)
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of the pavement. The data collection is typically triggered using a DMI mounted to the vehicle wheel or to an external distance wheel.
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Survey of Vendors The proposed NDT system specifications along with questionnaires were sent to GPR vendors and mechanical wave equipment manufacturers. Four GPR vendors and two mechanical wave equipment manufacturers responded.
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Identify Target Users Determining the target audience for the guidelines is an important step that precedes preparation of the document. The target audience must have a need for the equipment, funding to purchase the equipment, and a level of technical expertise to operate and analyze the data.
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8. Test Output Data Quality Control Check 9.
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CHAPTER 3 Pilot Workshops The original scope of this Phase 3 implementation effort included a focus on a pilot workshop effort by FHWA. Later, the scope was expanded to have the research team coordinate with FHWA and key NDT vendors (3d-Radar and Olson Engineering)
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Poor weather conditions restricted representatives from other DOTs from attending. The program included presentations by Dr.
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made by the device. When an antenna array is used, the density of tests (rows of data)
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CHAPTER 4 Summary and Conclusions Phase 3 of this SHRP 2 study prepared user guidelines for using GPR and SASW/IE NDT technologies to detect delamination in asphalt pavements. The research team solicited input from NDT equipment vendors so the guidelines would accurately reflect the capability of each technology.
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