Concrete–fiber-reinforced polymer interfacial bond monitoring with self-triggering sensors

Abstract

External bonding with fiber-reinforced polymers is currently one of the most popular technologies for rehabilitation of concrete structures. However, the effectiveness of the technology largely depends on the strength of the bond between the fiber-reinforced polymer laminate and the concrete substrate. This article provides a system to monitor the loss of bond between the fiber-reinforced polymer laminate and the concrete. Fiber optic sensors are broadly accepted as a structural health monitoring device for fiber-reinforced polymer materials by integrating the sensors into the host material. A recent development in fiber optic sensor technology is the mechanoluminescence-based optoelectronic sensors. Concrete beams strengthened with multifunctional fiber-reinforced polymer laminates were tested in shear using these sensors to evaluate the bond strength of the composite system. The sensors showed response to shear stress transfer in the adhesive layer which was observed to be as low as 2 MPa. The inclusion of sensors does not affect the bond strength (3.35 MPa), for both beams with sensors and without sensors. Real-time failure detection of fiber-reinforced polymer–strengthened beams was successfully achieved in this study. In future, the scheme aims at providing a tool to reduce the response time and decision making involved in the maintenance of deficient structures.

Multiscale Simulation Approach to Localized Interfacial Bonding and Stress -State Analysis of Self-Triggering Sensors

“…Compared to previous FE results, the multi-scale simulation yields a more defined load vs extension curve, exemplifying the high-fidelity results garnered from propagating stress phenomena throughout the multiple scales. The previous study used ABAQUS CAE to simulate the shear loading with a model that had a 150mm bond length, but did not have a modeled sensor [11]. However, in this study, it is intended to show the introduction of a more varied, and therefore realistic response in the loading of a material expected to produce a non-linear load vs extension plot.…”

“…However, in this study, it is intended to show the introduction of a more varied, and therefore realistic response in the loading of a material expected to produce a non-linear load vs extension plot. The multi-scale results are plotted versus a single-scale FE simulation below in figure 7 [11]. With a reasonably accurate global representation of the concrete samples, the local stress transferred to the sensor model and the TL particles can be investigated.…”

“…Given the particles do not require an external energy source, they are "self-triggering" and therefore have great potential for integration in next-generation material structures. These particles have been employed as a coating for fiber optic cores which net "sensors" with triboluminescent qualities [11]. The introduction of mechanical stress creates a strain in the coating that induces the production of light that is transferred through the core and can be used to determine failure [11].…”

“…These particles have been employed as a coating for fiber optic cores which net "sensors" with triboluminescent qualities [11]. The introduction of mechanical stress creates a strain in the coating that induces the production of light that is transferred through the core and can be used to determine failure [11]. The sensors in this study are made with a polymethyl methacrylate (PMMA) optical core, coated with Zinc-Sulfide Manganese (ZnS:Mn) particles.…”

“…Experimental data was collected using fabricated concrete specimens and bonded carbon fiber composite laminates with an embedded TL sensor as per the experimental specifications of Joshi, Pollard, et al [11]. The concrete represents a damaged structure in the field, which is in need of repair.…”