The manuscript and poster “NDT Sensor Fusion in Structural Pavement Condition Surveys” introducing the RPB HealTec concept were presented at the InfraMation conference in Las Vegas on the 28th of September. InfraMation is the world’s largest thermal imaging conference.
An article introducing the RPB HealTec project in the context of the new approach in structural road condition surveys was published in the Highways magazine (August-September 2016 issue). This magazine has over 12,500 subscribers of the digital version and circulation of 7000 print copies.
The analysis of the sensor fusion results for the data acquired during the field trials on the A22 Brennero Motorway showed that the combination of the sensor outputs (GPR and IRT, especially) provides more information on the road pavement subsurface condition than the individual sensors as well as increasing the degree of validity of the survey results.
Moreover, the cross-referencing of the individual sensor outputs should be used for verification of the “existence” of the detected defects in order to decrease the number of false positive alarms. For instance, while the GPR analysis showed to be efficient in the detection of subsurface defects such as delaminations between the layers and material/structural changes as well as the sites of transition between the road pavement and bridge deck, IRT provides the segregation map for the entire lane thus allowing assessment of the condition of the regions not covered by the GPR antennas as well as the “global picture” of road surface around the detected defects.
The corresponding examples include delaminations close to the lane borderline, deteriorated joint in the middle of the lane, structural changes (e.g., patching and overlays), local variations in the material properties (e.g., trapped moisture, asphalt degradation), surface defects (e.g., cracking, potholes), etc. In general, it was concluded that IRT significantly extends the quality of the subsurface condition information extracted from GPR, while ACU can be used as an additional tool for mapping of the surface level defect locations and changes in the material properties.
The final RPB HealTec system configuration was implemented in May 2016 on the premises of the A22 Brennero Motorway.
Integration of the multi-sensor system was performed on the software and hardware levels for the main NDT sensors: GPR, IRT and ACU as well as the spatial referencing equipment: INS/GPS and DMI.
Installation of GSSI SIR 30 GPR system with 900 MHz and 1.6 GHz antennas for subsurface structure assessment and detection of defects and deterioration areas:
DR.HILLGER ACU system with 75 KHz transducers for profiling of the surface layer condition and identification of the changes in the asphalt material properties:
FLIR A655SC IRT camera for inspection of the structural condition of the top asphalt layers based on the analysis of segregation patterns in combination with HDV for spatial referencing and detection of surface defects:
Hardware and software level integration for synchronised sensor data acquisition:
The “Trend Deviation Analysis for Automated Detection of Defects in GPR Data for Road Condition Surveys” paper was presented at the 23rd International Conference on Systems, Signals and Image Processing (IWSSIP) 2016 conference in Bratislava, Slovak Republic: IWSSIP_2016_RPB_HealTec_GPR_processing .
It covered the underlying principle of the proposed trend deviation analysis of GPR data for automated detection of subsurface detects, structural changes and deterioration areas in road pavement structural condition surveys.
The Fifth Technical meeting took place on the 29th of January 2016 and was hosted by CITY, London, UK.
Partners discussed the project progress including the GPR, IRT, HDV, ACU and GPS/INS sensor equipment acquisition (hardware and SDK), the results of laboratory and preliminary field testing, hardware and software level system integration, post-processing software development and dissemination activities along with the organisational questions and further planning for the next 6 months.
At the present stage of the project, the individual NDT sensor modules (WP2-4) were identified and implemented and the WP5-6 teams are working on the system integration involving. For instance, in addition to the power supply, wiring, and central control unit, the hardware integration solution also involves manufacturing of additional holders for protection of the equipment, additional sensors for environmental condition measurement, distance measuring instrument (DMI), etc. The software integration focuses on the development of the software and GUI for synchronized data acquisition and storage and system performance control (i.e., remote sensor control). The post-processing software provides access to the survey data (i.e., synchronized and GIS-mapped sensor output display) and performs data analysis for identification of the road pavement areas that can potentially contain defects or structural changes (both surface and subsurface) based on the decision-level fusion of multidimensional sensor outputs.
The next stage of the project will focus on organisation of the field trials of the integrated solutions followed by further optimization of integrated hardware and software system prototype configuration along with formalization of the plan for dissemination and exploitation activities based on the existing highway maintenance standards and promotion through the trade magazines.
The meeting concluded with an agreement that given the successes achieved so far the next meeting is to be scheduled for the end of March in order to coincide with the field test trials that are going to take place in Athens (CERTH).
The “NDT Sensor Fusion: Optimisation of NDT Sensor Data Processing Strategies for Road Infrastructure Inspection” paper was presented at Universities’ Transport Study Group (UTSG) 2016 conference in Bristol, UK: RPB_HealTec_UTSG_2016.pdf.
It covered the underlying principles of the proposed RPB HealTec concept of multidimensional NDT sensor fusion for structural road condition survey.
Two papers on NDT sensor fusion and ACU transducer positioning were presented withing the NDT session at the 22nd International Conference on Systems, Signals and Image Processing (IWSSIP) 2015 conference in London, UK.
The First Project Review meeting took place on the 28th of May 2015 and was hosted by CITY, London, UK.
Partners present the up-to-date progress and planning in the ongoing workpackages to the Project Officer and Project Reviewer. The first reporting period saw successful completion of WP1 “System Specification” and Milestone MS2 was passed with the NDT technologies being operational. The project RTD partners are working on integration of GPR, IRT and ACU systems on hardware and software levels (WP2-6) with expert advice from the SMEs, while WP8 team is planning dissemination activities for the next year.
The Third Technical meeting took place on the 13th of March 2015 and was hosted by CERTH, Athens, Greece.
Partners discussed the project progress including the defined system specifications based on FEM simulation results and preliminary laboratory testing along with the organisational questions and further planning for the next reporting period.
The research carried out to determine the suitability of the selected techniques showed promising preliminary results in location of surface and sub-surface defects. GPR has been used to assess pavement construction and condition at traffic speed for several years, and the proof of concept presented at the meeting justified its selection. The other two techniques, Thermography and Air Coupled Ultrasonics, may be less familiar to pavement engineers but successful early trials presented encouraging data.
The next stage of the project will establish the design and construction requirements for a prototype collection platform along with the required fusion software to combine all data sets.
The meeting concluded with an agreement that given the successes achieved so far promotion of the RBP Healtec system should be implemented, and the next meeting has been scheduled for the end of May.