scholarly journals Compressive Behavior and Analytical Model of Ultra-Early Strength Concrete-Filled FRP Tube With Zero Curing Time

2022 ◽  
Vol 8 ◽  
Author(s):  
Yue Liu ◽  
Jia-Zhan Xie ◽  
Jing-Liang Yan
Keyword(s):  
Compressive Strength ◽  
Fiber Reinforced Polymer ◽  
Curing Time ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Early Strength ◽  
Frp Tube

Fiber-reinforced polymer (FRP) has been widely used in civil engineering due to its light weight, high strength, convenient construction, and strong corrosion resistance. One of the important applications of FRP composites is the concrete-filled FRP tube (CFFT), which can greatly improve the compressive strength and ductility of concrete as well as facilitate construction. In this article, the compressive performances of a normal concrete-filled FRP tube (N-CFFT) column with 5-hour curing time and an ultra-early strength concrete-filled FRP tube (UES–CFFT) column with zero curing time were studied by considering the characteristics of rapid early strength improvement of ultra-early strength concrete and the confinement effect of the FRP tube. Monotonic axial compression tests were carried out on 3 empty FRP tubes (FTs) without an internal filler and 6 CFFT (3 N-CFFTs and 3 UES-CFFTs) specimens. All specimens were cylinders of 200 mm in diameter and 600 mm in height, confined by glass fiber–reinforced polymer (GFRP). Test results indicated that the compressive bearing capacity of the specimens increased significantly by adopting the ultra-early strength concrete as the core concrete of the CFFT, although the curing time was zero. It was also shown that the compressive behavior of the UES–CFFT specimens with zero curing time increased significantly than that of the N-CFFT specimens with 5-hour curing time because the former was able to achieve rapid strength enhancement in a very short time than the latter. The ultimate compressive strength of UES–CFFT specimens with zero curing time reached 78.3 MPa, which was 66.2 and 97.2% higher than that of N-CFFT with 5-hour curing time and FT specimens, respectively. In addition, a simple confinement model to predict the strength of UES–CFFT with zero curing time in ultimate condition was introduced. Compared with the existing models, the proposed model could predict the ultimate strength of UES–CFFT specimens with zero curing time with better accuracy.

scholarly journals Compressive Strength Testing of Hybrid Concrete-Filled Fiber-Reinforced Plastic Tubes Confined by Filament Winding

2021 ◽  
Vol 11 (7) ◽  
pp. 2900
Author(s):  
In-Kyu Kang ◽  
Sun-Hee Kim
Keyword(s):  
Compressive Strength ◽  
High Strength ◽  
Maximum Error ◽  
Filament Winding ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Reinforced Polymer ◽  
Reinforced Plastic ◽  
Frp Tube

In this study, an experiment on compressive strength of the hybrid concrete-filled fiber-reinforced polymer (FRP) tube (CFFT) confined by filament winding was conducted to improve the longitudinal strength while considering the thickness of filament winding as a variable. A maximum error of 17% was observed when the results of performing the finite element analysis (FEA) by applying the mechanical properties of the fiber-reinforced polymer (FRP) materials suggested in previous studies were compared to those of the compressive strength experiment on the hybrid-CFFT. Moreover, a maximum error of 15% was exhibited when the results derived from the strength equation proposed by analyzing the compressive strength experiment were compared. Furthermore, the compressive strength of the hybrid-CFFT increased by up to 14% when the longitudinal compressive strength of the pre-tensioned spun high strength concrete (PHC) pile and concrete-filled tube (CFT) were compared.

Concrete-Filled FRP Tubes: New Forms for Improved Confinement Effectiveness

2012 ◽  
Vol 256-259 ◽  
pp. 657-661
Author(s):  
Togay Ozbakkloglu
Keyword(s):  
Experimental Study ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Similar Material ◽  
Reinforced Polymer ◽  
Improved Performance ◽  
Frp Tube ◽  
Frp Tubes

This paper reports on the development and testing of a new concrete-filled fiber reinforced polymer (FRP) tube (CFFT) system. The CFFT system was designed to enhance the effectiveness of rectangular FRP tubes in confining concrete. The technique used in the development of the CFFT system involved the incorporation of an internal FRP panel as an integral part of the CFFT. The performance of the system was investigated experimentally through axial compression tests of six unique CFFTs. The results of the experimental study indicate that the new CFFT system presented in this paper offer significantly improved performance over conventional CFFTs with similar material and geometric properties. Examination of the test results have led to a number of significant conclusions in regards to confinement effectiveness of each new CFFT system. These results are presented and a discussion is provided on the parameters that influenced the compressive behavior of the new CFFT system.

Compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes as internal reinforcements

2019 ◽  
Vol 23 (4) ◽  
pp. 713-732 ◽  
Author(s):  
Shu Fang ◽  
Li-Juan Li ◽  
Tao Jiang ◽  
Bing Fu
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Small Diameter ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Polymer Tubes

Concrete infilled in a small-diameter fiber-reinforced polymer tube is strongly confined, thus having a high compressive strength and excellent deformability. Such a feature is exploited in the development of two types of high-performance hybrid members at Guangdong University of Technology, China, by incorporating small-diameter (30 to 60 mm) concrete-filled fiber-reinforced polymer tubes as internal reinforcements. Understanding the compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes is essential to understanding the behavior of the proposed hybrid members and the development of their design approaches. This article therefore presents a systematic study on the axial compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes with the test parameters being the thickness, diameter, and fiber type of fiber-reinforced polymer tubes and concrete strength. The test results show that the tested small-diameter concrete-filled fiber-reinforced polymer tubes have a compressive strength and an ultimate axial strain of up to 267 MPa and 10.3%, which are, respectively, about 6 and 34 times that of the corresponding unconfined specimens, demonstrating the great potential of small-diameter concrete-filled fiber-reinforced polymer tubes as internal reinforcements for use in high-performance hybrid members. The applicability of three widely accepted stress–strain models developed based on test results of fiber-reinforced polymer-confined concrete cylinders with a diameter of 150 mm or above is also examined. It is shown that the three models tend to predict a steeper second portion of stress–strain responses than the test results, revealing the need of a tailored stress–strain model for small-diameter concrete-filled fiber-reinforced polymer tubes.

Effect of fiber angles on normal- and high-strength concrete-filled fiber-reinforced polymer tubes under monotonic axial compression

2019 ◽  
Vol 23 (5) ◽  
pp. 924-940
Author(s):  
Bing Zhang ◽  
Xia-Min Hu ◽  
Qing Zhao ◽  
Tao Huang ◽  
Ning-Yuan Zhang ◽  
...  
Keyword(s):  
Axial Compression ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Absolute Value ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Polymer Tube ◽  
Polymer Tubes

Concrete-filled fiber-reinforced polymer tubes are a novel form of composite columns, which are particularly attractive for structural members in harsh environments and seismic regions due to their corrosion resistance and ductile behavior. Over the past two decades, many studies have been conducted on concrete-filled fiber-reinforced polymer tubes under axial compression, and many stress–strain models have been proposed. However, existing studies mainly focused on concrete-filled fiber-reinforced polymer tubes with only hoop fibers. In order to investigate the effect of fiber angles (i.e. the fiber angle between the fiber orientation and the longitudinal axis of fiber-reinforced polymer tube), this study conducted axial compression tests of 42 concrete-filled fiber-reinforced polymer tubes with ±80°, ±60°, or ±45° fiber angles. These concrete-filled fiber-reinforced polymer tubes were constructed using normal-strength concrete or high-strength concrete. Fiber-reinforced polymer tube thickness was also investigated as an important parameter. In order to clarify the effect of fiber angles on the properties of fiber-reinforced polymer tubes, axial compression tests on 15 short fiber-reinforced polymer tubes and tensile split-disk tests on 75 fiber-reinforced polymer rings were conducted. Experimental results indicate that fiber angles had significant influences on the hoop properties of fiber-reinforced polymer tube; the confinement effect of fiber-reinforced polymer tube and the peak stress of the confined concrete decreased with the decrease of the absolute value of fiber angles, while the ultimate strain of the confined concrete increased with the decrease of the absolute value of fiber angles. Two existing stress–strain models, which were developed mainly on test results of concrete confined by fiber-reinforced polymer tubes with only hoop fibers, are capable of providing reasonably accurate predictions for concrete-filled fiber-reinforced polymer tubes with ±80° and ±60° fiber angles, but it underestimates the ultimate axial strain of concrete-filled fiber-reinforced polymer tubes with ±45° fiber angles.

scholarly journals Compressive Strength of Modified FRP Hybrid Bars

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1898
Author(s):  
Marek Urbański
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Basalt Fiber ◽  
Test Method ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Free Length ◽  
Compression Properties ◽  
Reinforced Polymer ◽  
Frp Bars

A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.

Compressive Behavior of Circular Concrete Columns Confined by Basalt Fiber Reinforced Polymer (BFRP)

2018 ◽  
Vol 765 ◽  
pp. 355-360 ◽  
Author(s):  
Sakol Suon ◽  
Shahzad Saleem ◽  
Amorn Pimanmas
Keyword(s):  
Basalt Fiber ◽  
Concrete Columns ◽  
Primary Objective ◽  
Fiber Reinforced Polymer ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Reinforced Polymer ◽  
Ductile Behavior ◽  
Basalt Fiber Reinforced Polymer

This paper presents an experimental study on the compressive behavior of circular concrete columns confined by a new class of composite materials originated from basalt rock, Basalt Fiber Reinforced Polymer (BFRP). The primary objective of this study is to observe the compressive behavior of BFRP-confined cylindrical concrete column specimens under the effect of different number of layers of basalt fiber as a study parameter (3, 6, and 9 layers). For this purpose, 8 small scale circular concrete specimens with no internal steel reinforcement were tested under monotonic axial compression to failure. The results of BFRP-confined concrete specimens of this study showed a bilinear stress-strain response with two ascending branches. Consequently, the performance of confined columns was improved as the number of BFRP layer was increased, in which all the specimens exhibited ductile behavior before failure with significant strength enhancement. The experimental results indicate the well-performing of basalt fiber in improving the concrete compression behavior with an increase in number of FRP layers.

A Simple Design-Oriented Model for FRP-Confined High-Strength Concrete

2013 ◽  
Vol 743 ◽  
pp. 45-49
Author(s):  
Jian Chin Lim ◽  
Togay Ozbakkloglu
Keyword(s):  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Simple Design ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Strength Enhancement ◽  
Reinforced Polymer ◽  
Test Database

This paper presents a study on the axial compressive behavior of fiber reinforced polymer (FRP)-confined high-strength concrete (HSC). A large experimental test database assembled from the published literature was used to investigate and quantify factors influencing the compressive behavior of FRP-confined HSC. The database consisted of 976 test data having unconfined concrete strength ranging from 6.2 to 169.7MPa. Based on the analysis results of the database, it was found that the threshold confinement stiffness increases significantly with an increase in concrete strength, which in turn adversely affects the strength enhancement of confined concrete. It was also observed that the hoop rupture strain of FRP shell decreases with an increase in concrete strength. Existing confinement models that are applicable to FRP-confined HSC were assessed using the database. Finally, a new simple design-oriented model for FRP-confined HSC developed on the basis of the database is presented.

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