Monitoring Concrete Deterioration Due to Reinforcement Corrosion by Integrating Acoustic Emission and FBG Strain Measurements.

Weijie Li,Gangbing Song,Bo Wang,Siu Ho,Changhang Xu

doi:10.3390/s17030657

Abstract

Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface.

Highlights

IntroductionReinforced concrete (RC) structures constitute the majority of civil infrastructures of the world
Reinforced concrete (RC) structures constitute the majority of civil infrastructures of the world.Corrosion of concrete reinforcement members has been recognized as one of the predominant deterioration mechanisms for steel reinforced concrete structures
These two different corrosion monitoring methods interpret the phenomenon of reinforcement corrosion two different corrosion monitoring methods interpret the phenomenon of reinforcement corrosion from two different aspects; one is from acoustic emission aspects and the other is from expansive from two different aspects; one is from acoustic emission aspects and the other is from expansive strain strain development aspects

Summary

Introduction

Reinforced concrete (RC) structures constitute the majority of civil infrastructures of the world. Corrosion of concrete reinforcement members has been recognized as one of the predominant deterioration mechanisms for steel reinforced concrete structures. The two major factors responsible for corrosion of steel reinforcement are carbonation of concrete and chloride penetration. The passivation of steel within the concrete is broken down and indicates the initiation of reinforcement corrosion. The corrosion products are usually two to six times more voluminous than the original steel consumed [1], resulting in the generation of expansive pressure exerted by corrosion products to the surrounding concrete. Damage due to reinforcement corrosion occurs in the form of cover cracking, reduction of the steel cross-sectional area, and deterioration of a concrete–steel interface bond [2]

Results

Discussion

Conclusion