Soft coatings are popularly applied in industry to prevent corrosion for structural steel. However, coatings cannot fully prevent corrosion from happening. In this paper, an inline corrosion monitoring system for steel was extended to steel with soft coating based on fiber Bragg grating sensors (FBGs). Experimental results show that an increase in central wavelength of FBGs can be detected if corrosion occurs under soft coatings. A positive relationship between the status of corrosion and the increase in central wavelength was also observed. This study revealed the potential of FBGs to serve as corrosion assessment technique for steel protected with soft coatings.
A corrosion monitoring system for steel using Fiber Bragg grating (FBG) sensors is proposed. FBG sensors were protected by hypodermic tubes and a layer of adhesive. The increase in volume caused by the presence of corrosion product introduces strain that can be monitored by FBG sensors. Experimental results showed a positive correlation between the strain and corrosion product, and the change in central wavelength has the potential to serve as an indicator for material weight loss due to corrosion.
Most transportation agencies now collect pavement roughness data using the inertial profilers, which requires instrumented vehicles and technicians with specialized training to interpret the results. The extensive labor requirements of the profiling activities limit data collection for portions of the national highway system to at most once per year, resulting in outdated roughness data for decision making of maintenance needs. In this paper, a real-time roughness evaluation method was developed by linking the output of durable in-pavement strain sensors to road roughness level. The durable in-pavement sensors will continuously provide information of road roughness in real time after they are installed and calibrated during the road construction until the service life of the associated pavement. Field tests validated the developed strain method by comparison with standard inertial profiling method and the connected-vehicle method. The comparison of the results from the field tests approves the effectiveness of the developed road roughness evaluation method using in-pavement strain sensors, which can be further applied practically for needed concrete pavements.