Continuous Bituminous Pavement Stripping Assessment Through Non-destructive Testing

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General Information
Study Number: TPF-5(504)
Former Study Number:
Lead Organization: Minnesota Department of Transportation
Solicitation Number: 1569
Partners: FHWA, FL, GADOT, IL, KY, MN, MO, MS, TN, TX
Status: Cleared by FHWA
Est. Completion Date:
Contract/Other Number:
Last Updated: Feb 13, 2024
Contract End Date:
Financial Summary
Contract Amount:
Suggested Contribution:
Total Commitments Received: $1,075,000.00
100% SP&R Approval: Approved
Contact Information
Lead Study Contact(s): Eyoab Zegeye
eyoab.zegeye@state.mn.us
FHWA Technical Liaison(s): Stephen Cooper
Stephen.J.Cooper@dot.gov
Phone: 443-257-7145
Organization Year Commitments Technical Contact Name Funding Contact Name
Federal Highway Administration 2023 $150,000.00 Stephen Cooper Stephen Cooper
Florida Department of Transportation 2024 $25,000.00 Charles Holzschuher Jennifer Clark
Florida Department of Transportation 2025 $25,000.00 Charles Holzschuher Jennifer Clark
Florida Department of Transportation 2026 $25,000.00 Charles Holzschuher Jennifer Clark
Florida Department of Transportation 2027 $25,000.00 Charles Holzschuher Jennifer Clark
Georgia Department of Transportation 2023 $25,000.00 Ian Rish Brennan Roney
Georgia Department of Transportation 2024 $25,000.00 Ian Rish Brennan Roney
Georgia Department of Transportation 2025 $25,000.00 Ian Rish Brennan Roney
Georgia Department of Transportation 2026 $25,000.00 Ian Rish Brennan Roney
Illinois Department of Transportation 2023 $25,000.00 Brian Hill John Senger
Illinois Department of Transportation 2024 $25,000.00 Brian Hill John Senger
Illinois Department of Transportation 2025 $25,000.00 Brian Hill John Senger
Illinois Department of Transportation 2026 $25,000.00 Brian Hill John Senger
Kentucky Transportation Cabinet 2024 $25,000.00 Brad Frazier Jarrod Stanley
Kentucky Transportation Cabinet 2025 $25,000.00 Brad Frazier Jarrod Stanley
Kentucky Transportation Cabinet 2026 $25,000.00 Brad Frazier Jarrod Stanley
Minnesota Department of Transportation 2023 $25,000.00 Eyoab Zegeye Leif Halverson
Minnesota Department of Transportation 2024 $25,000.00 Eyoab Zegeye Leif Halverson
Minnesota Department of Transportation 2025 $25,000.00 Eyoab Zegeye Leif Halverson
Minnesota Department of Transportation 2026 $25,000.00 Eyoab Zegeye Leif Halverson
Minnesota Department of Transportation 2027 $25,000.00 Eyoab Zegeye Leif Halverson
Mississippi Department of Transportation 2023 $25,000.00 Jim Poorbaugh Robert Vance
Mississippi Department of Transportation 2024 $25,000.00 Jim Poorbaugh Robert Vance
Mississippi Department of Transportation 2025 $25,000.00 Jim Poorbaugh Robert Vance
Mississippi Department of Transportation 2026 $25,000.00 Jim Poorbaugh Robert Vance
Missouri Department of Transportation 2023 $25,000.00 Jonathan Varner Jennifer Harper
Missouri Department of Transportation 2024 $25,000.00 Jonathan Varner Jennifer Harper
Missouri Department of Transportation 2025 $25,000.00 Jonathan Varner Jennifer Harper
Missouri Department of Transportation 2026 $25,000.00 Jonathan Varner Jennifer Harper
Missouri Department of Transportation 2027 $25,000.00 Jonathan Varner Jennifer Harper
Tennessee Department of Transportation 2023 $25,000.00 Xiaoyang Jia David Lee
Tennessee Department of Transportation 2024 $25,000.00 Xiaoyang Jia David Lee
Tennessee Department of Transportation 2025 $25,000.00 Xiaoyang Jia David Lee
Tennessee Department of Transportation 2026 $25,000.00 Xiaoyang Jia David Lee
Texas Department of Transportation 2023 $25,000.00 Ruben Carrasco Ned Mattila
Texas Department of Transportation 2024 $25,000.00 Ruben Carrasco Ned Mattila
Texas Department of Transportation 2025 $25,000.00 Ruben Carrasco Ned Mattila
Texas Department of Transportation 2026 $25,000.00 Ruben Carrasco Ned Mattila

Study Description

Stripping is a critical pavement subsurface distress affecting the performance and durability of asphalt pavement systems: full-depth asphalt, recycled, or composite. In full-depth asphalt pavements, stripping can be caused by moisture infiltration in the pavement system, leading to the loss of bond between the aggregate particles and the asphalt binder composing the mixture. The bond failure leads to the formation of an unbonded mixture and ultimately reduces the pavement bearing capacity. In asphalt overlays over concrete (composite), stripping is generally caused by moisture trapped in the interface above the concrete. Stripping leads to the formation of potholes, cracking, slippage cracking, tearing, and ultimately reduced strength and serviceability of pavements if not detected and addressed early.

Over the years, substantial progress has been made in developing bituminous mixtures less prone to stripping, thanks mainly to improved material selection tools, anti-stripping additives, modified asphalt binders, and improved drainage practices. However, stripping continues to be a dominant issue in pavement design and scoping processes for various reasons. To cite a few examples: a) placing new stripping-resistant mixtures on top of old bituminous mixtures that are likely to be affected by stripping; b) increased use of recycled and multi-recycled materials; and c) asphalt overlays on concrete and d) quality control-related section or spot failures (i.e., binder content deficiency).

The most challenging aspect of stripping is that it initiates at the bottom or middle of bituminous layers and propagates upward. Hence, it is almost impossible to detect and quantify at early stages through visual inspections or traditional pavement forensic investigation tools. Once the problem manifests itself on the top surface of the pavement, it is generally too late for minor localized treatments. The lack of appropriate diagnostic tools for stripping makes developing proper pavement rehabilitation plans challenging. For instance, without knowing the stripping's extent, severity, and depth, it becomes challenging to select an appropriate mill depth for a new overlay or a proper rehabilitation strategy (i.e., full reconstruction, mill and overlay, cold recycling).

Fortunately, new advanced non-destructive evaluation (NDE) technologies are becoming increasingly accessible and suitable for solving complex pavement issues. The Strategic Highway Research Program 2 (SHRP2) study R06D (Heitzman, et al. 2012) vetted the capability of several NDE technologies to evaluate pavements affected by delamination: stripping and debonding. Debonding is a similar failure that occurs when the tacking between the pavement layers (lifts) is inadequate. However, the affected layers generally remain physically quasi-intact in debonding, while the layers exhibit full or partial deterioration in stripping. Out of eight (8) vetted tools, two (2) provided promising results for identifying and quantifying stripping: the 3D-Ground Penetrating Radar (3D-GPR), an air-launched antenna array with frequency sweep measurements and the Impact Echo/Spectral Analysis of Surface Waves (IE/SASW) scanning system. Among these two technologies, 3D-GPR provided the added advantage of continuous full-lane width data collection in a single pass at safe traffic traveling speeds. Furthermore, the ability of 3D-GPR to scan full-lane width resulted in higher chances of detecting stripping locations than more traditional single-channel 2D-GPR systems. While in the case of debonding, 3D-GPR was less effective and offered good information only in wet conditions. The IE/SASW was most effective at identifying discontinuities when the pavement was cold and stiff. However, it required lane closure and did not provide continuous full-lane coverage.

After the R06D study, several states (FL, TX, NM, CA, KY and MN) participated in an Implementation Assistance Program (IAP) sponsored by FHWA and AASHTO, aimed at determining if the 3D-GPR and the IE/SASW technologies met "proof of concept" and were ready for national implementation. The study concluded that the 3D-GPR system met the criteria for high-speed data collection. The IE/SASW system significantly improved data collection speed but still requires lane closure. The IAP identified several drawbacks and concerns that need to be addressed to effectively use 3D-GPR in detecting stripping at project and network levels. The recommended needs for improvements are listed below:

·         Develop standard practices for testing pavement using 3D-GPR and other companion NDE technologies such as Traffic Speed Deflectometer and Falling Weight Deflectometer

·         Establish proper equipment calibration and data quality verification (i.e., coring locations and numbers) procedures to improve the accuracy of the output

·         Develop a standard algorithm for automated processing of 3D-GPR data and detection of stripping. At present, identifying stripping in the bituminous layers is accomplished through a visual examination of the GPR images. This process is significantly dependent on the person's experience interpreting the images, time-consuming and labor-intensive, and difficult to adopt in state agencies' practices.

·         Determine the need and benefits of linking the 3D-GPR data to other NDE technologies. 3D-GPR alone cannot identify stripping all the time and at all subsurface moisture conditions. In addition, 3D-GPR is only readily available to some road agencies. Hence, it is important to continue evaluating other NDE technologies that could fill in the blank spots of 3D-GPR. The other NDE technologies proposed for this study are TSD, FWD, 1D-GPR, IE/SASW, and PASP.

·         Develop specifications and implementation plans and promote the use of 3D-GPR for testing stripping

·         Facilitate communication between vendors and agencies to enable vendors to make improvements to their hardware and software

·         Establish a national user group to provide a venue for experts in NDE technologies to advance GPR and other NDE technologies in local and national road authorities.

In September 2021, FHWA sponsored a well-attended Virtual Peer Exchange to gather updates on Post-R06D advancements from state agencies, universities, research institutions, consultants and vendor perspectives. The meeting noted that several state transportation agencies, including the Minnesota Department of Transportation (MNDOT), are working toward incorporating 3D-GPR in their project scoping process and addressing stripping and other subsurface pavement issues in their roadways. The group reiterated the need to address the IAP recommendations through a national pool fund study. MnDOT was selected to lead and manage the pool fund study efforts, including drafting and advancing the present proposal. MnDOT recognizes the opportunities and challenges of this effort and believes they are best addressed in collaboration with other agencies and stakeholders.

Objectives

The primary objective of the proposed pooled-fund project is to develop a methodology for rapid and automatic detection of stripping in bituminous pavements using 3D-GPR and other NDE technologies.  As per the IAP and R06D findings and recommendations, particular emphasis will be placed on using 3D-GPR, which is particularly suitable for high-speed continuous and lane-width data collection and is already being incorporated in project scoping processes for thickness determination. Nevertheless, other NDE technologies, such as FWD and TSD, will also be considered to complement, evaluate, verify and validate the 3D-GPR findings. Similarly, recognizing that 3D-GPR alone cannot identify stripping all the time and at all subsurface moisture conditions, the study will also investigate using IE/SASW, MIRA, and Thermal Imaging for localized spot verifications. Furthermore, the proposed pool fund study will include contemporary 2D and 3D-GPR testing on limited projects to compare and identify advantages and disadvantages. The tools (i.e., equipment, testing procedures, data processing algorithms, specifications) advanced through this project will assist state transportation agencies in rapidly and confidently detecting the extent, depth, and severity of stripping in their roads.  The set goals are to be accomplished by:

·         Developing a methodology for rapid and automatic stripping detection based on 3D-GPR and other NDE technologies such as Falling Weight Deflectometer (FWD) and Traffic Speed Deflectometer (TSD). The development will be based on the experience and needs of participants so that the developed methodology can effectively and efficiently support their pavement evaluation program.

·         Developing a software for automated processing of 3D-GPR data and detection of stripping

·         Verifying and validating the developed methodology on projects selected by the participating agencies. The more states, the stronger the methodology

·         Providing participating agencies guidelines on data collection and analysis protocols

·         Drafting AASHTO specification.

·         Facilitating and supporting communication between experts in NDE technologies, state engineers and vendors to advance the use of GPR for inspecting pavement subsurface issues

·         Providing training and technical assistance that includes providing support for specification development and strategies for agency full implementation

·         Conducting technology promotion for the technologies

Scope of Work

The work plan will be finalized and approved by the pool fund panel. While the details and scope of the objectives will be further defined during the first task of the project, it is anticipated that the project will include the followings:

·         Task 1 – Finalizing the Scope of Work

·         Task 2 – Survey and Literature Review

·         Task 3 – Building GPR Signal Stripping Signature Database

·         Task 4 – Building and Evaluating Artificially Stripped Section in MN ROAD

·         Task 5 – Development of a Software for Automated Detection and Quantification of Stripping

·         Task 6 – Data collection on Roads from Participant States

·         Task 7- Review, Analysis, Data Fusion, and Interpretation of the collected data

·         Task 8 – Development of AASHTO Specification - Testing and Analysis Procedures

·         Task 9 – Training and Technical Assistance

·         Task 10 – Support and Communication

·         Task 11 – Strategic Technology Promotion

A summary of the technical and non-technical project activities is given in the diagrams below. Full description of the task item can be find in the attached document.




Comments

This project is expected to have a minimum participation of at least seven agencies. Minimum annual commitment of $25,000 per year per agency for four years within Fiscal Years 2023-2027.

Documents Attached
Title File/Link Type Privacy Download
RFP for Development of analysis tools for automatic detection and rating of stripping - Addendum WWW POSTED DBE SPECIAL PROVISIONS 1055223-37550764-v1.PDF Request for Proposals Public
RFP for Development of analysis tools for automatic detection and rating of stripping - Scope WWW POSTED SCOPE 1055223-37550766-v1 (1).PDF Request for Proposals Public
RFP for Development of analysis tools for automatic detection and rating of stripping WWW POSTED RFP 1055223-37553328-v1 (1).PDF Request for Proposals Public
TPF5-504 Summary of survey responses _slides. pptx TPF5-504 Summary of survey responses _slides. pptx.pdf Memorandum Public
TPF-5 (504) Survey questionaries TPF-5 (504) Survey questionaries_ v2.pdf Memorandum Public
TPF 5(504) - First In Person Meeting Minutes Nov 2023 TPF 5(504) - First InPerson Meeting -Minutes Nov 2023.pdf Other Public
TPF-5 (504) Quarterly Report - Q4 2023 TPF-5 (504) Quarterly Report 2023-Q4.pdf Quarterly Progress Report Public
TPF-5 (504) Quarterly Report - Q3 2023 TPF-5 (504) Quarterly Report 2023-Q3.pdf Quarterly Progress Report Public
Construction plans for the stripping section built in MnROAD (draft drawings) TPF5-504 MnROAD Test Sections.xlsx Memorandum Public
Construction plans for the stripping section built in MnROAD (draft) MnROAD - Construction plans for the stripping section (draft).pdf Memorandum Public
TPF-5 (504) Quarterly Report - Q2 2023 TPF-5 (504) Quarterly Report 2023-Q2.pdf Quarterly Progress Report Public
TPF-5 (504) Quarterly Report - Q1 2023 TPF-5 (504) Quarterly Report 2023-Q1.pdf Quarterly Progress Report Public
Project kick-off meeting notes Project Kickoff Meeting Notes.pdf Other Public
TPF-5(504)-Project Charter and work plan TPF5-504 Project Charter V02_120122.pdf Work Plan Public
Letter of Acceptance TPF-5(504) Letter of Acceptance.pdf Memorandum Public
Documents Attached
Title File/Link Type Privacy Download
Approval of SPR Waiver State Led Approval SPR Waiver Memo#1569.pdf Memorandum Public
Bituminous Pavement Stripping Pooled Fund Study Proposal MNDOT_DOCS-#15853238-v1-Bituminous_Pavement_Stripping_Pooled_Fund_Study_Proposal__Final.PDF Work Plan Public

Continuous Bituminous Pavement Stripping Assessment Through Non-destructive Testing

General Information
Study Number: TPF-5(504)
Lead Organization: Minnesota Department of Transportation
Solicitation Number: 1569
Partners: FHWA, FL, GADOT, IL, KY, MN, MO, MS, TN, TX
Status: Cleared by FHWA
Est. Completion Date:
Contract/Other Number:
Last Updated: Feb 13, 2024
Contract End Date:
Financial Summary
Contract Amount:
Total Commitments Received: $1,075,000.00
100% SP&R Approval:
Contact Information
Lead Study Contact(s): Eyoab Zegeye
eyoab.zegeye@state.mn.us
FHWA Technical Liaison(s): Stephen Cooper
Stephen.J.Cooper@dot.gov
Phone: 443-257-7145
Commitments by Organizations
Organization Year Commitments Technical Contact Name Funding Contact Name Contact Number Email Address
Federal Highway Administration 2023 $150,000.00 Stephen Cooper Stephen Cooper 443-257-7145 Stephen.J.Cooper@dot.gov
Florida Department of Transportation 2024 $25,000.00 Charles Holzschuher Jennifer Clark 850-414-4614 jennifer.clark@dot.state.fl.us
Florida Department of Transportation 2025 $25,000.00 Charles Holzschuher Jennifer Clark 850-414-4614 jennifer.clark@dot.state.fl.us
Florida Department of Transportation 2026 $25,000.00 Charles Holzschuher Jennifer Clark 850-414-4614 jennifer.clark@dot.state.fl.us
Florida Department of Transportation 2027 $25,000.00 Charles Holzschuher Jennifer Clark 850-414-4614 jennifer.clark@dot.state.fl.us
Georgia Department of Transportation 2023 $25,000.00 Ian Rish Brennan Roney 404-347-0595 broney@dot.ga.gov
Georgia Department of Transportation 2024 $25,000.00 Ian Rish Brennan Roney 404-347-0595 broney@dot.ga.gov
Georgia Department of Transportation 2025 $25,000.00 Ian Rish Brennan Roney 404-347-0595 broney@dot.ga.gov
Georgia Department of Transportation 2026 $25,000.00 Ian Rish Brennan Roney 404-347-0595 broney@dot.ga.gov
Illinois Department of Transportation 2023 $25,000.00 Brian Hill John Senger 217-782-8582 John.Senger@Illinois.gov
Illinois Department of Transportation 2024 $25,000.00 Brian Hill John Senger 217-782-8582 John.Senger@Illinois.gov
Illinois Department of Transportation 2025 $25,000.00 Brian Hill John Senger 217-782-8582 John.Senger@Illinois.gov
Illinois Department of Transportation 2026 $25,000.00 Brian Hill John Senger 217-782-8582 John.Senger@Illinois.gov
Kentucky Transportation Cabinet 2024 $25,000.00 Brad Frazier Jarrod Stanley (502) 782-4090 jarrod.stanley@ky.gov
Kentucky Transportation Cabinet 2025 $25,000.00 Brad Frazier Jarrod Stanley (502) 782-4090 jarrod.stanley@ky.gov
Kentucky Transportation Cabinet 2026 $25,000.00 Brad Frazier Jarrod Stanley (502) 782-4090 jarrod.stanley@ky.gov
Minnesota Department of Transportation 2023 $25,000.00 Eyoab Zegeye Leif Halverson Leif.Halverson@state.mn.us
Minnesota Department of Transportation 2024 $25,000.00 Eyoab Zegeye Leif Halverson Leif.Halverson@state.mn.us
Minnesota Department of Transportation 2025 $25,000.00 Eyoab Zegeye Leif Halverson Leif.Halverson@state.mn.us
Minnesota Department of Transportation 2026 $25,000.00 Eyoab Zegeye Leif Halverson Leif.Halverson@state.mn.us
Minnesota Department of Transportation 2027 $25,000.00 Eyoab Zegeye Leif Halverson Leif.Halverson@state.mn.us
Mississippi Department of Transportation 2023 $25,000.00 Jim Poorbaugh Robert Vance RVance@mdot.ms.gov
Mississippi Department of Transportation 2024 $25,000.00 Jim Poorbaugh Robert Vance RVance@mdot.ms.gov
Mississippi Department of Transportation 2025 $25,000.00 Jim Poorbaugh Robert Vance RVance@mdot.ms.gov
Mississippi Department of Transportation 2026 $25,000.00 Jim Poorbaugh Robert Vance RVance@mdot.ms.gov
Missouri Department of Transportation 2023 $25,000.00 Jonathan Varner Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2024 $25,000.00 Jonathan Varner Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2025 $25,000.00 Jonathan Varner Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2026 $25,000.00 Jonathan Varner Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Missouri Department of Transportation 2027 $25,000.00 Jonathan Varner Jennifer Harper 573-526-3636 Jennifer.Harper@modot.mo.gov
Tennessee Department of Transportation 2023 $25,000.00 Xiaoyang Jia David Lee David.Lee@tn.gov
Tennessee Department of Transportation 2024 $25,000.00 Xiaoyang Jia David Lee David.Lee@tn.gov
Tennessee Department of Transportation 2025 $25,000.00 Xiaoyang Jia David Lee David.Lee@tn.gov
Tennessee Department of Transportation 2026 $25,000.00 Xiaoyang Jia David Lee David.Lee@tn.gov
Texas Department of Transportation 2023 $25,000.00 Ruben Carrasco Ned Mattila 512-416-4727 ned.mattila@txdot.gov
Texas Department of Transportation 2024 $25,000.00 Ruben Carrasco Ned Mattila 512-416-4727 ned.mattila@txdot.gov
Texas Department of Transportation 2025 $25,000.00 Ruben Carrasco Ned Mattila 512-416-4727 ned.mattila@txdot.gov
Texas Department of Transportation 2026 $25,000.00 Ruben Carrasco Ned Mattila 512-416-4727 ned.mattila@txdot.gov

Study Description

Study Description

Stripping is a critical pavement subsurface distress affecting the performance and durability of asphalt pavement systems: full-depth asphalt, recycled, or composite. In full-depth asphalt pavements, stripping can be caused by moisture infiltration in the pavement system, leading to the loss of bond between the aggregate particles and the asphalt binder composing the mixture. The bond failure leads to the formation of an unbonded mixture and ultimately reduces the pavement bearing capacity. In asphalt overlays over concrete (composite), stripping is generally caused by moisture trapped in the interface above the concrete. Stripping leads to the formation of potholes, cracking, slippage cracking, tearing, and ultimately reduced strength and serviceability of pavements if not detected and addressed early.

Over the years, substantial progress has been made in developing bituminous mixtures less prone to stripping, thanks mainly to improved material selection tools, anti-stripping additives, modified asphalt binders, and improved drainage practices. However, stripping continues to be a dominant issue in pavement design and scoping processes for various reasons. To cite a few examples: a) placing new stripping-resistant mixtures on top of old bituminous mixtures that are likely to be affected by stripping; b) increased use of recycled and multi-recycled materials; and c) asphalt overlays on concrete and d) quality control-related section or spot failures (i.e., binder content deficiency).

The most challenging aspect of stripping is that it initiates at the bottom or middle of bituminous layers and propagates upward. Hence, it is almost impossible to detect and quantify at early stages through visual inspections or traditional pavement forensic investigation tools. Once the problem manifests itself on the top surface of the pavement, it is generally too late for minor localized treatments. The lack of appropriate diagnostic tools for stripping makes developing proper pavement rehabilitation plans challenging. For instance, without knowing the stripping's extent, severity, and depth, it becomes challenging to select an appropriate mill depth for a new overlay or a proper rehabilitation strategy (i.e., full reconstruction, mill and overlay, cold recycling).

Fortunately, new advanced non-destructive evaluation (NDE) technologies are becoming increasingly accessible and suitable for solving complex pavement issues. The Strategic Highway Research Program 2 (SHRP2) study R06D (Heitzman, et al. 2012) vetted the capability of several NDE technologies to evaluate pavements affected by delamination: stripping and debonding. Debonding is a similar failure that occurs when the tacking between the pavement layers (lifts) is inadequate. However, the affected layers generally remain physically quasi-intact in debonding, while the layers exhibit full or partial deterioration in stripping. Out of eight (8) vetted tools, two (2) provided promising results for identifying and quantifying stripping: the 3D-Ground Penetrating Radar (3D-GPR), an air-launched antenna array with frequency sweep measurements and the Impact Echo/Spectral Analysis of Surface Waves (IE/SASW) scanning system. Among these two technologies, 3D-GPR provided the added advantage of continuous full-lane width data collection in a single pass at safe traffic traveling speeds. Furthermore, the ability of 3D-GPR to scan full-lane width resulted in higher chances of detecting stripping locations than more traditional single-channel 2D-GPR systems. While in the case of debonding, 3D-GPR was less effective and offered good information only in wet conditions. The IE/SASW was most effective at identifying discontinuities when the pavement was cold and stiff. However, it required lane closure and did not provide continuous full-lane coverage.

After the R06D study, several states (FL, TX, NM, CA, KY and MN) participated in an Implementation Assistance Program (IAP) sponsored by FHWA and AASHTO, aimed at determining if the 3D-GPR and the IE/SASW technologies met "proof of concept" and were ready for national implementation. The study concluded that the 3D-GPR system met the criteria for high-speed data collection. The IE/SASW system significantly improved data collection speed but still requires lane closure. The IAP identified several drawbacks and concerns that need to be addressed to effectively use 3D-GPR in detecting stripping at project and network levels. The recommended needs for improvements are listed below:

·         Develop standard practices for testing pavement using 3D-GPR and other companion NDE technologies such as Traffic Speed Deflectometer and Falling Weight Deflectometer

·         Establish proper equipment calibration and data quality verification (i.e., coring locations and numbers) procedures to improve the accuracy of the output

·         Develop a standard algorithm for automated processing of 3D-GPR data and detection of stripping. At present, identifying stripping in the bituminous layers is accomplished through a visual examination of the GPR images. This process is significantly dependent on the person's experience interpreting the images, time-consuming and labor-intensive, and difficult to adopt in state agencies' practices.

·         Determine the need and benefits of linking the 3D-GPR data to other NDE technologies. 3D-GPR alone cannot identify stripping all the time and at all subsurface moisture conditions. In addition, 3D-GPR is only readily available to some road agencies. Hence, it is important to continue evaluating other NDE technologies that could fill in the blank spots of 3D-GPR. The other NDE technologies proposed for this study are TSD, FWD, 1D-GPR, IE/SASW, and PASP.

·         Develop specifications and implementation plans and promote the use of 3D-GPR for testing stripping

·         Facilitate communication between vendors and agencies to enable vendors to make improvements to their hardware and software

·         Establish a national user group to provide a venue for experts in NDE technologies to advance GPR and other NDE technologies in local and national road authorities.

In September 2021, FHWA sponsored a well-attended Virtual Peer Exchange to gather updates on Post-R06D advancements from state agencies, universities, research institutions, consultants and vendor perspectives. The meeting noted that several state transportation agencies, including the Minnesota Department of Transportation (MNDOT), are working toward incorporating 3D-GPR in their project scoping process and addressing stripping and other subsurface pavement issues in their roadways. The group reiterated the need to address the IAP recommendations through a national pool fund study. MnDOT was selected to lead and manage the pool fund study efforts, including drafting and advancing the present proposal. MnDOT recognizes the opportunities and challenges of this effort and believes they are best addressed in collaboration with other agencies and stakeholders.

Objectives

The primary objective of the proposed pooled-fund project is to develop a methodology for rapid and automatic detection of stripping in bituminous pavements using 3D-GPR and other NDE technologies.  As per the IAP and R06D findings and recommendations, particular emphasis will be placed on using 3D-GPR, which is particularly suitable for high-speed continuous and lane-width data collection and is already being incorporated in project scoping processes for thickness determination. Nevertheless, other NDE technologies, such as FWD and TSD, will also be considered to complement, evaluate, verify and validate the 3D-GPR findings. Similarly, recognizing that 3D-GPR alone cannot identify stripping all the time and at all subsurface moisture conditions, the study will also investigate using IE/SASW, MIRA, and Thermal Imaging for localized spot verifications. Furthermore, the proposed pool fund study will include contemporary 2D and 3D-GPR testing on limited projects to compare and identify advantages and disadvantages. The tools (i.e., equipment, testing procedures, data processing algorithms, specifications) advanced through this project will assist state transportation agencies in rapidly and confidently detecting the extent, depth, and severity of stripping in their roads.  The set goals are to be accomplished by:

·         Developing a methodology for rapid and automatic stripping detection based on 3D-GPR and other NDE technologies such as Falling Weight Deflectometer (FWD) and Traffic Speed Deflectometer (TSD). The development will be based on the experience and needs of participants so that the developed methodology can effectively and efficiently support their pavement evaluation program.

·         Developing a software for automated processing of 3D-GPR data and detection of stripping

·         Verifying and validating the developed methodology on projects selected by the participating agencies. The more states, the stronger the methodology

·         Providing participating agencies guidelines on data collection and analysis protocols

·         Drafting AASHTO specification.

·         Facilitating and supporting communication between experts in NDE technologies, state engineers and vendors to advance the use of GPR for inspecting pavement subsurface issues

·         Providing training and technical assistance that includes providing support for specification development and strategies for agency full implementation

·         Conducting technology promotion for the technologies

Scope of Work

The work plan will be finalized and approved by the pool fund panel. While the details and scope of the objectives will be further defined during the first task of the project, it is anticipated that the project will include the followings:

·         Task 1 – Finalizing the Scope of Work

·         Task 2 – Survey and Literature Review

·         Task 3 – Building GPR Signal Stripping Signature Database

·         Task 4 – Building and Evaluating Artificially Stripped Section in MN ROAD

·         Task 5 – Development of a Software for Automated Detection and Quantification of Stripping

·         Task 6 – Data collection on Roads from Participant States

·         Task 7- Review, Analysis, Data Fusion, and Interpretation of the collected data

·         Task 8 – Development of AASHTO Specification - Testing and Analysis Procedures

·         Task 9 – Training and Technical Assistance

·         Task 10 – Support and Communication

·         Task 11 – Strategic Technology Promotion

A summary of the technical and non-technical project activities is given in the diagrams below. Full description of the task item can be find in the attached document.




Comments

This project is expected to have a minimum participation of at least seven agencies. Minimum annual commitment of $25,000 per year per agency for four years within Fiscal Years 2023-2027.

Title File/Link Type Private
Letter of Acceptance TPF-5(504) Letter of Acceptance.pdf Memorandum Public
Construction plans for the stripping section built in MnROAD (draft) MnROAD - Construction plans for the stripping section (draft).pdf Memorandum Public
Construction plans for the stripping section built in MnROAD (draft drawings) TPF5-504 MnROAD Test Sections.xlsx Memorandum Public
TPF-5 (504) Survey questionaries TPF-5 (504) Survey questionaries_ v2.pdf Memorandum Public
TPF5-504 Summary of survey responses _slides. pptx TPF5-504 Summary of survey responses _slides. pptx.pdf Memorandum Public
Project kick-off meeting notes Project Kickoff Meeting Notes.pdf Other Public
TPF 5(504) - First In Person Meeting Minutes Nov 2023 TPF 5(504) - First InPerson Meeting -Minutes Nov 2023.pdf Other Public
TPF-5 (504) Quarterly Report - Q1 2023 TPF-5 (504) Quarterly Report 2023-Q1.pdf Quarterly Progress Report Public
TPF-5 (504) Quarterly Report - Q2 2023 TPF-5 (504) Quarterly Report 2023-Q2.pdf Quarterly Progress Report Public
TPF-5 (504) Quarterly Report - Q3 2023 TPF-5 (504) Quarterly Report 2023-Q3.pdf Quarterly Progress Report Public
TPF-5 (504) Quarterly Report - Q4 2023 TPF-5 (504) Quarterly Report 2023-Q4.pdf Quarterly Progress Report Public
RFP for Development of analysis tools for automatic detection and rating of stripping WWW POSTED RFP 1055223-37553328-v1 (1).PDF Request for Proposals Public
RFP for Development of analysis tools for automatic detection and rating of stripping - Scope WWW POSTED SCOPE 1055223-37550766-v1 (1).PDF Request for Proposals Public
RFP for Development of analysis tools for automatic detection and rating of stripping - Addendum WWW POSTED DBE SPECIAL PROVISIONS 1055223-37550764-v1.PDF Request for Proposals Public
TPF-5(504)-Project Charter and work plan TPF5-504 Project Charter V02_120122.pdf Work Plan Public
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Approval of SPR Waiver State Led Approval SPR Waiver Memo#1569.pdf Memorandum Public
Bituminous Pavement Stripping Pooled Fund Study Proposal MNDOT_DOCS-#15853238-v1-Bituminous_Pavement_Stripping_Pooled_Fund_Study_Proposal__Final.PDF Work Plan Public

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