Bond Behaviour between GFRP Reinforcement and Concrete Using a Pull-Out Test

2018 ◽  
Vol 272 ◽  
pp. 232-237
Author(s):  
Natalia Gažovičová ◽  
Juraj Bilčík ◽  
Ivan Hollý ◽  
Jaroslav Halvonik
Keyword(s):  
Test Methods ◽  
Steel Reinforcement ◽  
Fiber Reinforced Polymers ◽  
Mechanical Interlocking ◽  
Bond Behaviour ◽  
Reinforced Polymers ◽  
Rc Structures ◽  
Pull Out ◽  
Corrosion Of Steel ◽  
Gfrp Reinforcement

Corrosion of steel reinforcement is one of the most often deterioration reasons of RC structures. At present, the corrosion of steel reinforcement can be avoided by using non-metallic reinforcement from composite materials, especially in structures that are exposed to extreme environmental environment. These materials are durable and non-conductive. They are composited from two materials: fibres and matrix. The most commonly used FRP (Fiber Reinforced Polymers - FRP) reinforcement are glass fibre reinforced polymers (GFRP). The bar surface can be e.g. sanded, wrapped, with helically wound ribs. The bond between concrete and reinforcement is one of the basic requirements for the composite action of both materials. The transfer of forces between the steel reinforcement and the concrete is provided by the following mechanisms: adhesion, friction and mechanical interlocking. The bond between GFRP reinforcement and concrete is different and it is ensured by friction and mechanical interlocking of the rebar surface. The chemical bond does not originate between GFRP reinforcement and the surrounding concrete, so adhesion does not contribute to transfer of the bond forces. Some few test methods are used to determine the bond between GFRP reinforcement and concrete. The pull-out test were used to determine the bond behaviour between GFRP rebars and concrete. This paper describes the preparation, process, results and evaluation of the pull-out tests.

Bond of GFRP Reinforcement with Concrete

2016 ◽  
Vol 691 ◽  
pp. 356-365 ◽  
Author(s):  
Ivan Hollý ◽  
Juraj Bilčík ◽  
Ondrej Keseli ◽  
Natalia Gažovičová
Keyword(s):  
Steel Reinforcement ◽  
Reinforcing Bars ◽  
Tunnel Boring Machines ◽  
Rc Structures ◽  
Factors Affecting ◽  
Glass Fiber Reinforcement ◽  
Boring Machines ◽  
Electromagnetic Transparency ◽  
Corrosion Of Steel ◽  
Gfrp Reinforcement

Corrosion of steel reinforcement is the major cause of deterioration of existing RC structures. Combined effects of moisture, temperature, and chlorides reduce the alkalinity of concrete and exacerbate the corrosion of steel reinforcement, especially for concrete structures subjected to aggressive environments, such as marine structures and bridges and parking garages exposed to de-icing salts. Glass fiber reinforcement polymer (GFRP) bars are suitable alternatives to steel bars in reinforced concrete applications if durability, electromagnetic transparency, or ease of demolition in temporary constructions is sought, that have to be demolished partially by tunnel boring machines (TBMs). The bond of GFRP reinforcement is different from steel reinforcing bars. This paper presents factors affecting the bond strength between GFRP reinforcement and concrete.

Experimental Investigation of Bond between GFRP Reinforcement and Concrete

2020 ◽  
Vol 309 ◽  
pp. 140-145
Author(s):  
Ivan Hollý
Keyword(s):  
Test Methods ◽  
Transport Infrastructure ◽  
Mechanical Interlocking ◽  
Composite Action ◽  
Pull Out ◽  
Steel Bars ◽  
Glass Fiber Reinforcement ◽  
High Alkalinity ◽  
Gfrp Reinforcement ◽  
Gfrp Rebars

The reinforcing steel embedded in concrete is generally protected against corrosion by the high alkalinity (pH = 12.5 to 13.5) of the concrete pore solution. The structural degradation of concrete structures due to reinforcement’s corrosion has an impact on the safety, serviceability and durability of the structure. The corrosion of reinforcements in the construction of a transport infrastructure (especially bridges), parking areas, etc., is primarily initiated by chlorides from de-icing salts. Glass fiber reinforcement polymer (GFRP) bars are suitable alternatives to steel bars in reinforced concrete applications. The bond between concrete and reinforcement is one of the basic requirements for the composite action of both materials. The transfer of forces between the steel reinforcement and the concrete is provided by the following mechanisms: adhesion, friction and mechanical interlocking. The bond between GFRP reinforcement and concrete is different and it is ensured by friction and mechanical interlocking of the rebar surface. The chemical bond does not originate between GFRP reinforcement and the surrounding concrete, so adhesion does not contribute to transfer of the bond forces. Some few test methods are used to determine the bond between GFRP reinforcement and concrete. The pull-out tests were used to determine the bond behavior between GFRP rebars and concrete. This paper describes the preparation, process, results and evaluation of the pull-out tests.

Influence of Test Configuration on Bond Strength of GFRP Bars

2019 ◽  
Vol 292 ◽  
pp. 217-223 ◽  
Author(s):  
Ondřej Janus ◽  
Frantisek Girgle ◽  
Vojtech Kostiha ◽  
Petr Štěpánek ◽  
Pavel Sulak
Keyword(s):  
Bond Strength ◽  
Concrete Cover ◽  
Silica Sand ◽  
Beam Test ◽  
Bond Behaviour ◽  
Test Configuration ◽  
Gfrp Bars ◽  
Pull Out ◽  
Frp Reinforcement ◽  
Gfrp Reinforcement

It is well-known that test configuration affects bond behaviour of steel reinforcement, but this effect has not yet been sufficiently quantified when using FRP reinforcement. This paper presents partial results from an ongoing experimental programme that deals with the bond strength of GFRP bars with concrete, with regards to the effect of the surface treatment of the rebars and test configuration. A modified beam test is presented in this study along with a pull-out test with an eccentric bar placement. The bond strength of GFRP reinforcement with sand-coated treatment using silica sand and ribbed type with milled ribs was tested. The sand-coated bars exhibit different bond behaviour compared to the ribbed ones due to different forces transfer from the reinforcement to the concrete. Thickness of the concrete cover layer also has a significant effect on the bond behaviour of the reinforcement.

scholarly journals Bond-Slip Models for FPR-Concrete Interfaces Subjected to Moisture Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Justin Shrestha ◽  
Dawei Zhang ◽  
Tamon Ueda
Keyword(s):  
Fiber Reinforced Polymers ◽  
Experimental Investigations ◽  
Reinforced Polymers ◽  
Bond Slip ◽  
Exposure Effect ◽  
Pull Out ◽  
Proposed Model ◽  
Maximum Period ◽  
Moisture Conditions

Environmental related durability issues have been of great concerns in the structures strengthened with the fiber reinforced polymers (FRPs). In marine environment, moisture is one of the dominant factors that adversely affect the material properties and the bond interfaces. Several short-term and long-term laboratory experimental investigations have been conducted to study such behaviors but, still, there are insufficient constitutive bond models which could incorporate moisture exposure conditions. This paper proposed a very simple approach in determining the nonlinear bond-slip models for the FRP-concrete interface considering the effect of moisture conditions. The proposed models are based on the strain results of the experimental investigation conducted by the authors using 6 different commercial FRP systems exposed to the moisture conditions for the maximum period of 18 months. The exposure effect in the moisture conditions seems to have great dependency on the FRP system. Based on the contrasting differences in the results under moisture conditions, separate bond-slip models have been proposed for the wet-layup FRP and prefabricated FRP systems. As for the verification of the proposed model under moisture conditions, predicted pull-out load was compared with the experimental pull-out load. The results showed good agreement for all the FRP systems under investigation.

scholarly journals An Experimental Interpretation of High-Performance Fiber-Reinforced Polymer Concrete with FNN Paradigms

2020 ◽  
Vol 8 (5) ◽  
pp. 2624-2632
Keyword(s):  
High Performance ◽  
Fiber Reinforced Polymers ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Rc Structures ◽  
Fuzzy Neural ◽  
High Performance Fiber ◽  
Design Defects ◽  
The Impact

Strengthening and enhancing of Reinforced Concrete (RC) structural components are important to broaden its administration period, overcoming the first structure limits and to limit the impact of construction defects as well as the design defects. In this work, Fiber Reinforced Polymers (FRPs) is utilized as to strengthen RC structures. In this paper, the utilization of FRP such as Sisal, Jute, and Coir in concrete structures is being examined for its viability in upgrading structural execution both regarding strength and ductility. The structural behavior of FRP specimen is examined by experimental and numerical examination by estimating the parameters, for example, compressive strength, tensile strength, ductility, and deflection. Here, we utilized the Fuzzy Neural Network (FNN) procedure to test the strength of specimen. At the point, when compared with existing work, the proposed FNN model achieves the greatest performance in terms of all parameters for the fiber reinforced specimen under various loaded condition.

scholarly journals Evaluation of the Performance and Ductility Index of Concrete Structures Using Advanced Composite Material Strengthening Methods

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4239
Author(s):  
Tae-Kyun Kim ◽  
Jong-Sup Park
Keyword(s):  
Prestressed Concrete ◽  
Evaluation Method ◽  
Concrete Structures ◽  
Area Ratio ◽  
Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Rc Structures ◽  
Ductility Index ◽  
Concrete Crack ◽  
Index Evaluation

The performance of concrete structures deteriorates over time. Thus, improving their performance using fiber-reinforced polymers (FRPs), PS strands, and various strengthening methods is important. Reinforced concrete (RC) and prestressed concrete (PSC) structures develop initial cracks in concrete during bending tests, and destruction occurs over a certain period of time after a certain load is generated, and then after the reinforcements and strands yield. However, in the case of FRP structures, after an initial concrete crack occurs, FRPs exhibit a rapid shape deformation of the structure after yielding. Thus, in this study we used FRP and PS strand materials and evaluated the ductility index using the load-displacement results obtained from structural tests conducted using various strengthening methods. The ductility index evaluation method compares and analyzes the change rates in the ductility index of PSC and RC structures based on a method that uses structural deflection and the derivation of the energy area ratio. The ductility evaluation results based on the energy area ratio at the crack, yield, and ultimate points showed that all the RC structures, except for the specimens strengthened with reinforcing materials from company H, were in the ductility and semi-ductility sections. Thus, all the PSC structures, except for the control specimens and PH4NP, were found to be brittle.

Seismic Performance of Corroded RC Circular Columns Strengthened with Hybrid Fiber Reinforced Polymers

2011 ◽  
Vol 266 ◽  
pp. 192-195
Author(s):  
Jian Hui Li ◽  
Zhao Zhong Chang ◽  
Ying Li ◽  
Zong Cai Deng
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Maximum Displacement ◽  
Rc Columns ◽  
Reinforced Polymers ◽  
Displacement Ductility ◽  
Corrosion Of Steel

In order to research the seismic performance of strengthening corroded RC circular columns with hybrid Fiber Reinforced Polymer (FRP) sheets, ten RC columns were tested under cyclic load and constant axial. Test phenomena are described, experimental data are analyzed and compared, and the effect of the axial compression ratio and stirrup reinforcement ratio on the seismic behavior is studied. Results show that the corrosion of steel bars may introduce the brittle failure for RC columns in some extent, and the seismic performance can be enhanced effectively for RC columns strengthened with hybrid FRP. Ductility and energy dissipation are improved significantly, but the bearing capacity can be only increased within limits. When the degree of rebar corrosion is 5.1%, the maximum displacement ductility factor and accumulated energy dissipation of the strengthened corroded columns are 123% and 12.5 times larger respectively than that of the un-strengthened corroded columns.

SAFETY ENHANCEMENT OF URBAN STRUCTURES WITH STRUCTURAL RECOVERABILITY AND CONTROLLABILITY

2009 ◽  
Vol 03 (03) ◽  
pp. 143-174 ◽  
Author(s):  
ZHISHEN WU ◽  
MOHAMED F. M. FAHMY ◽  
GANG WU
Keyword(s):  
Damage Control ◽  
Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Rc Structures ◽  
Experimental Database ◽  
Structure Damage ◽  
Urban Structures ◽  
A New Technique ◽  
Novel Concept ◽  
Rc Bridge Columns

The novel concept presented in this paper is the use of fiber reinforced polymers (FRP) to control the performance of new and existing reinforced concrete (RC) structures during and after moderate to strong earthquakes. This study was conducted in three major steps. First, an overview of the different concepts considered to improve both the pre- and post-earthquake performances of new infrastructures is presented. Second, a mechanical model for FRP-RC structure damage control is defined. Third, based on the proposed definition for controllable structures and using the post-yield stiffness and permanent deformations as seismic performance measures, the results of scaled tests of different structural elements are examined. For virgin beams, strengthening new RC beams or those with initial damage using hybrid FRP are presented, and the results of using wet bonding between FRP and concrete as a new technique for the construction of structures are briefly discussed. In addition, the effectiveness of FRP jacketing in existing non-ductile RC bridge columns with different deficiencies for quick recoverability after an earthquake is scrutinized using a large experimental database. Finally, to achieve a recoverable and more durable structure, the performance of steel bars wound with different types of FRP as reinforcement is highlighted.

Shear Performance of Reinforced Concrete Beams with GFRP

2020 ◽  
Vol 1002 ◽  
pp. 531-540
Author(s):  
Suaad K. Ibraheem Al-Fadhli
Keyword(s):  
Load Capacity ◽  
Glass Fibers ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Glass Fiber Reinforced ◽  
Shear Performance ◽  
Practical Program

"Fiber Reinforced Polymers FRP" provide good alternatives to regular reinforcing steel, as their resistance to environmental factors specifies them and provide durability, in addition to their appropriate prices. These polymers are of various compositions and forms, some of which have a basic composition of glass fibers, others contain carbon or additional materials. They have used instead of steel reinforcement as the main longitudinal rebar, also as laminates that can be attached to the concrete surfaces for shear or flexural resistance. In this study, "Glass Fiber Reinforced Polymers GFRP" has tested for shear performance, where a practical program has applied. Three "simply supported beams" as control specimens have been prepared and tested, with the other nine beams with different combinations of reinforcement of steel and GFRP for flexure and shear resistance. Specimens have examined and the results have analyzed. The results showed that the use of GFRP as for main reinforcement with GFRP laminates instead of shear steel reinforcement increases the load capacity by 11%, also decreases the deflection by 46%.

scholarly journals Enhancement of Mechanical Integrity of Advanced Composites using PMAA-Electropolymerised CF Fabrics

2018 ◽  
Vol 188 ◽  
pp. 01007
Author(s):  
Dionysios A. Semitekolos ◽  
Panagiotis Goulis ◽  
Despoina I. Batsouli ◽  
Elias P. Koumoulos ◽  
Loukas Zoumpoulakis ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Structural Integrity ◽  
Fiber Reinforced Polymers ◽  
Nanoindentation Test ◽  
Mechanical Interlocking ◽  
Hot Press ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Advanced Composites

The aim of the present study is the development of new composite materials that show improved mechanical and structural integrity. In order to accomplish this goal, a novel functionalization method of the carbon fibers for the reinforcement of the composites surface was investigated. Through the electrografting of methacrylic acid onto the surface of the carbon fiber, this treatment aims to selectively modify the surface of the carbon fabrics, in order to create active groups that can chemically react with the epoxy resin, under heat and pressure. By this way, better adhesion as mechanical interlocking between the resin and the reinforcement can be achieved. The surface treatment was examined qualitatively by means of Infrared spectroscopy, Scanning Electron Microscopy and Raman spectroscopy. The carbon fiber reinforced polymers were manufactured via the hot-press technique and they were subsequently submitted to flexural, shear and nanoindentation test. Finally, the internal structural integrity was tested through micro-Computing Tomography.

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