Evaluating the Performance of Functionalized Carbon Structures with Integrated Optical Fiber Sensors under Practical Conditions.

Kort Bremer,Lourdes Alwis,Yulong Zheng,Frank Weigand,Michael Kuhne,Marco Krüger,Reinhard Helbig,Bernhard Roth

doi:10.3390/s18113923

Abstract

An Optical Frequency Domain Reflectometry (OFDR) based fiber optic sensor scheme “embedded” in concrete for the purpose of structural health monitoring (SHM) of carbon concrete composites (C3) is presented. The design, while strengthening the concrete structure, also aims to monitor common SHM parameters such as strain and cracks. This was achieved by weaving the carbon fiber together with optical fiber, based on a specialized technique that uses an embroidery setup where both the carbon and optical fiber are woven on a water dissolvable polymer substrate. The performance of the sensing scheme was characterized in-situ utilizing the OFDR based technique and the results presented. The sensors embedded on a custom made concrete block were subjected to varying strain via a three point bending test to destruction and the results discussed. The intended dual-achievement of the scheme thus proposed in SHM and strengthening the C3 is demonstrated. The suitability of the OFDR scheme for C3 is combined with a fibre Bragg grating (FBG)-based approach, and discussed in detail.

Highlights

The project Carbon Concrete Composite (C3 ) is one of the largest research programmes in the field of building constructions in Germany at present, aiming to replace traditional steel reinforced concrete (SRC) as building material by carbon reinforced concrete (CRC)
The functionalised carbon structures (FCSs) have been embedded in concrete blocks and the sensor performance was evaluated using a 3-point bending test
Was closely monitored and only negligible attenuation variation of the light propagating in the optical fiber was detected, which can be attributed to connector tolerances

Summary

Introduction

The project Carbon Concrete Composite (C3 ) is one of the largest research programmes in the field of building constructions in Germany at present, aiming to replace traditional steel reinforced concrete (SRC) as building material by carbon reinforced concrete (CRC). The use of fiber optic sensors (FOSs) for Structural Health Monitoring (SHM) of reinforced concrete structures is state of the art and within this domain, FOSs are utilized mainly to monitor corrosion of the reinforcing steel and to measure the deformation of the reinforced concrete. FOSs are applied both on the surface of reinforced concrete [5,6]

Methods

Results

Conclusion