Enhancing Non-Destructive Testing for GFRP Concrete at uOttawa
Enhancing Non-Destructive Testing for GFRP Concrete at uOttawa
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Researchers: Dr. Martin Noël (uOttawa) & Yasmine Kamagate (uOttawa)
Industry: Civil Engineering Research / NDT
Application: Glass Fiber Reinforced Polymer (GFRP) Structures
Overview: Measuring New Variables
Overview: Measuring New Variables
Researchers Martin Noël and Yasmine Kamagate faced a unique challenge: Glass Fiber Reinforced Polymer (GFRP) bars are corrosion-resistant but difficult to detect with standard Ground Penetrating Radar (GPR) due to their electrical similarity to concrete. By installing Apidae Systems’ compact, battery-powered data loggers directly onto the slabs, the team successfully correlated internal moisture and temperature levels with GPR readings, establishing new baselines for infrastructure maintenance without external power requirements.
The Challenge: The "Invisible" Reinforcement
The Challenge: The "Invisible" Reinforcement
GFRP is a valuable alternative to steel in bridge decks and parking garages because it resists corrosion from deicing salts. However, this material presents a significant detection challenge for maintenance crews.
The Conductivity Problem: Unlike steel, which shows up clearly on radar scans, GFRP has dielectric properties very similar to concrete, making it difficult to distinguish signal from noise using Ground Penetrating Radar (GPR).
The Missing Variable: The research team hypothesized that the concrete's electrical properties—and thus the visibility of the GFRP bars—change based on internal temperature and humidity.
Lack of Suitable Tools: The lab previously relied on thermocouples for high-temperature fire testing but lacked a portable solution to monitor internal humidity and temperature over long periods in outdoor, fluctuating environments.
"The challenge is that... GFRP's conductivity is similar to concrete, making it difficult to detect. Our hypothesis is that the electrical properties depend on humidity and temperature." — Dr. Martin Noël, Researcher
The Solution: Embedded, Portable Monitoring
The Solution: Embedded, Portable Monitoring
The research team required a logging solution that was unobtrusive. It had to fit inside the concrete slab without acting as a confounding variable in the GPR scans.
Key Implementation Features:
Zero Interference Form Factor: The loggers were compact enough to fit inside the slab and provided reliable results without interfering with the concrete or GFRP signals.
True Portability: The researchers needed to move slabs between indoor controlled environments and outdoor exposure sites. Apidae’s battery-powered, standalone design eliminated the need for tethered power supplies.
Long-Term Durability: The units were capable of monitoring internal conditions from the initial "wet" cure state (100% humidity) through the drying process over several seasons.
The Results
The Results
The deployment allowed the team to bridge the gap between accelerated lab tests and real-world environmental conditions.
New Data Correlations: The team is working to establish a new correlation point, using the data collected by Apidae System’s devices, between internal environment and GPR clarity, helping to develop future guidelines for infrastructure owners.
Seamless Data Collection: The wireless, battery-operated design meant researchers could collect data easily without managing complex wiring or power sources in the field.
Validated Reliability: The system provided clear, consistent data that matched researcher expectations,
"The data is really clear... They're really easy to use and it's easy for me to collect data." — Yasmine Kamagate, Researcher
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