Flexural Pseudo-Ductility Effect in Hybrid GFRP/CFRP Bars under Static Loading Conditions.

Szymon Duda,Marek Lubecki,Paweł Zielonka,Paweł Stabla,Grzegorz Ziółkowski,Grzegorz Lesiuk

doi:10.3390/ma14195608

Szymon Duda, Marek Lubecki + Show 4 more

Open Access

https://doi.org/10.3390/ma14195608

Copy DOI

Abstract

The problem with composite rebars in the civil engineering industry is often described as the material’s brittleness while overloaded. To overcome this drawback, researchers pay attention to the pseudo-ductility effect. The paper presents four-point bending tests of pure unidirectional (UD) rods with additional composite layers obtained by filament winding and hand braiding techniques. Two types of core materials, glass FRP (fibre reinforced polymer) and carbon FRP, were used. Regarding the overwrapping material, the filament winding technique utilized carbon and glass roving reinforcement in the epoxy matrix, while in the case of hand braiding, the carbon fibre sleeve was applied with the epoxy matrix. Microstructural analysis using scanning electron microscopy (SEM) and computed tomography (CT) was performed to reveal the structural differences between the two proposed methods. Mechanical test results showed good material behaviour exhibiting the pseudo-ductility effect after the point of maximum force. The two applied overwrapping techniques had different influences on the pseudo-ductility effect. Microstructural investigation revealed differences between the groups of specimens that partially explain their different characters during mechanical testing.

Highlights

The civil engineering industry, especially when considering reinforced concrete, demands high-performance materials in terms of durability, stiffness and corrosion resistance.The first two factors are fulfilled by steel rebars, which are nowadays widely used.the corrosion of steel is becoming an increasingly significant problem [1]
The results proved the pseudo-ductility effect of the strength was higher than that of conventional steel reinforcement
For the CF case, after the rapid decline of the force, an additional stiffness remained, which resulted in a significant rise of the reaction force to around 75% of the maximum observed force

Summary

Introduction

The civil engineering industry, especially when considering reinforced concrete, demands high-performance materials in terms of durability, stiffness and corrosion resistance.The first two factors are fulfilled by steel rebars, which are nowadays widely used.the corrosion of steel is becoming an increasingly significant problem [1]. The civil engineering industry, especially when considering reinforced concrete, demands high-performance materials in terms of durability, stiffness and corrosion resistance. The first two factors are fulfilled by steel rebars, which are nowadays widely used. The corrosion of steel is becoming an increasingly significant problem [1]. Fibre reinforced polymer (FRP) composite materials meet the previously mentioned demands. FRP materials are advantageous for their high corrosion resistance, high tensile strength, and high fatigue durability [2]. For the security of the building or structure, the reinforced concrete must not exhibit a rapid, brittle failure

Methods

Results

Conclusion