Experimental Investigation of the Fatigue Behavior of Basalt Fiber Reinforced Polymer Grid-Concrete Interface

Bo Wen,Chunfeng Wan,Lin Liu,Da Fang,Caiqian Yang

doi:10.1155/2020/9624154

Abstract

Fatigue behavior is an important factor for mechanical analysis of concrete members reinforced by basalt fiber reinforced polymer (BFRP) grid and polymer cement mortar (PCM) and plays a critical role in ensuring the safety of reinforced concrete bridges and other structures. In this study, on the basis of the static loading test results of concrete specimens reinforced by BFRP grid and PCM, a series of fatigue tests with different loading levels were conducted on interfaces between BFRP grid and concrete to investigate the fatigue behavior of BFRP grid-concrete interfaces. The test results indicate that with high loading level, the fatigue failure mode of interface is interfacial peeling failure while it transforms to the fatigue fracture of the BFRP grid under low loading level. The fatigue life (S-N) curves of BFRP grid-concrete interface are obtained and fitted in stages according to different failure modes, and the critical point of the two failure modes is pointed out. The relative slip evolution of interface during fatigue is further revealed in different stages with two failure modes, and the law of interface strain is studied with the increase of fatigue times. The relation of effective bonding length of interface and fatigue times is also described.

Highlights

Fiber reinforced polymer (FRP) is widely used in the reinforcement and repair of reinforced concrete structures owing to its numerous advantages [1]
Where ω is the total slip of the loading end under the load, ε0 is the strain measured by strain gauge G1 in the nonbonding area of the basalt fiber reinforced polymer (BFRP) grid, and l0 is the length of the nonbonding area with a value of 200 mm
Numerical fittings on fatigue test specimens with interfacial peeling failure (F-1, F-2, and F-3) and fatigue fracture of the BFRP grid (F4, F-5, and F-6) were separated to obtain the S-N curve expressions under different failure modes. e intersection of the two S-N curves is interpreted to represent the critical point of the two fatigue failure modes. e expression of the S-N curve between interface fatigue life and stress level can be expressed as

Summary

Introduction

Fiber reinforced polymer (FRP) is widely used in the reinforcement and repair of reinforced concrete structures owing to its numerous advantages (e.g., light weight, high strength, high environmental resistance, and strong designability) [1]. E interface behavior between FRP and concrete has been the focus of many studies and applications to ensure efficient improvement of structural performance [5, 6]. Organic polymer adhesives such as epoxy resins have particular disadvantages including rapid aging and poor environmental corrosion resistance. Previous studies have used inorganic materials (e.g., modified cement, fiber cement-based materials, and polymer mortar) as an interface adhesive in place of epoxy resin to improve durability of the FRP-concrete interface [7,8,9,10]. Previous studies have used inorganic materials (e.g., modified cement, fiber cement-based materials, and polymer mortar) as an interface adhesive in place of epoxy resin to improve durability of the FRP-concrete interface [7,8,9,10]. e combination of FRP grid and polymer mortar for structural strengthening improves component stiffness with better durability compared with traditional external FRP cloth and is more suitable for harsh reinforcement environments [11,12,13,14,15]

Methods

Results

Conclusion