PSI - Issue 64

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000 Available online at www.sciencedirect.com Procedia Structural Integrity 64 (2024) 293–300

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Rebar detection: Comparison of stepped frequency continuous wave and pulsed GPR Mercedes Solla a, *, Alexandre Novo b , Ahmed Elseicy a , F. Javier Prego c a CINTECX, GeoTech research group, Universidade de Vigo, 36310 Vigo, Spain Abstract Reinforced concrete structures are widely used in civil engineering owing to their versatility, strength, and durability. One of the most recommended methods for rebar mapping is Ground-Penetrating Radar (GPR) because of its non-destructive and non-invasive character. In concrete mapping, GPR is mainly used for locating subsurface objects (rebars, tendons, ducts), measuring concrete cover, mapping mesh configuration (spacing), and detecting bottom of slab. To achieve these, concrete scanning GPR practitioners often need very high-resolution images. This work presents a comparison in rebar mapping between two GPR systems with different modulation techniques: Stepped frequency continuous wave (SFCW) and pulsed radar. The SFCW system used has a frequency range of 400-6000 MHz, while the pulsed system used a ground-coupled central frequency antenna of 2.3 GHz. Measurements were conducted on laboratory specimens, with rebar diameters ranging from 8 to 32 mm. Three different specimens were used, with one for calibration and other two to analyze both the horizontal and vertical resolutions of the frequency antennas. SMAR 2024 – 7th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Rebar detection: Comparison of stepped frequency continuous wave and pulsed GPR Mercedes Solla a, *, Alexandre Novo b , Ahmed Elseicy a , F. Javier Prego c a CINTECX, GeoTech research group, Universidade de Vigo, 36310 Vigo, Spain b Screening Eagle Technologies, 29004 Malaga, Spain c EXTRACO S.A., R&D Department, 32004 Ourense, Spain Abstract Reinforced concrete structures are widely used in civil engineering owing to their versatility, strength, and durability. One of the most recommended methods for rebar mapping is Ground-Penetrating Radar (GPR) because of its non-destructive and non-invasive character. In concrete mapping, GPR is mainly used for locating subsurface objects (rebars, tendons, ducts), measuring concrete cover, mapping mesh configuration (spacing), and detecting bottom of slab. To achieve these, concrete scanning GPR practitioners often need very high-resolution images. This work presents a comparison in rebar mapping between two GPR systems with different modulation techniques: Stepped frequency continuous wave (SFCW) and pulsed radar. The SFCW system used has a frequency range of 400-6000 MHz, while the pulsed system used a ground-coupled central frequency antenna of 2.3 GHz. Measurements were conducted on laboratory specimens, with rebar diameters ranging from 8 to 32 mm. Three different specimens were used, with one for calibration and other two to analyze both the horizontal and vertical resolutions of the frequency antennas. Keywords: Ground-penetrating radar; rebar specimens; detection; frequency domain; time domain 1. Introduction In Transport Infrastructures (TI), many structures are made of Reinforced Concrete (RC), being rigid pavements and bridge decks those requiring frequent maintenance and servicing to ensure safety and functionality. Unfortunately, traditional inspection methods often struggle to detect damage originating from inside the structure (e.g. the initiation © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers b Screening Eagle Technologies, 29004 Malaga, Spain c EXTRACO S.A., R&D Department, 32004 Ourense, Spain Keywords: Ground-penetrating radar; rebar specimens; detection; frequency domain; time domain 1. Introduction In Transport Infrastructures (TI), many structures are made of Reinforced Concrete (RC), being rigid pavements and bridge decks those requiring frequent maintenance and servicing to ensure safety and functionality. Unfortunately, traditional inspection methods often struggle to detect damage originating from inside the structure (e.g. the initiation

* Corresponding author. Tel.: +34-699-419-032. E-mail address: merchisolla@uvigo.es

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers 10.1016/j.prostr.2024.09.250 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SMAR 2024 Organizers * Corresponding author. Tel.: +34-699-419-032. E-mail address: merchisolla@uvigo.es