Investigation of the Effects of Basalt Fibers on the Flexural Strength of RC Beams without Stirrups

The aim of the present paper is to study the mechanical properties of aluminate cement mortar mixed with different chopped fibers under high temperature. The specimens with a size of 40 mm ? 40 mm ? 160 mm is treated at various tempera?tures of 25?C, 200?C, 400?C, 600?C, and 800?C. The compressive and flexural strength of the aluminate cement mortar and its micro-structures are tested. The results show that the chopped steel fibers and basalt fibers are effective in improv?ing the high temperature mechanical properties of aluminate cement mortar. When the volume fraction of chopped steel fibers is 2%, the compressive strength and flexural strength of the test block treated at the temperature of 800?C increase by 18.3% and 128.6%, respectively.

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An experimental study on flexural strengthening of RC beams using CFRP sheets

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.16546 ◽

2018 ◽

Vol 7 (4) ◽

pp. 2075 ◽

Cited By ~ 4

Author(s):

Yasmin Murad

Keyword(s):

Flexural Strength ◽

Orientation Angle ◽

Longitudinal Axis ◽

Flexural Behavior ◽

Experimental Program ◽

Rc Beams ◽

Rc Structures ◽

Flexural Strengthening ◽

Cfrp Sheets ◽

Reinforced Polymer

The use of carbon fiber reinforced polymer (CFRP) sheets is becoming a widely accepted solution for strengthening and repairing rein-forced concrete (RC) structures. To date, the behavior of RC beams, strengthened with 60˚ and 45˚ inclined CFRP sheets, has not clearly explained. An experimental program is proposed in this paper to investigate the flexural behavior of RC beams strengthened with CFRP sheets. CFRP sheets were epoxy bonded to the tension face to enhance the flexural strength of beams inducing different orientation angles of 0˚, 45˚, 60˚ and 90˚ with the beam longitudinal axis. The study shows that strengthening RC beams with CFRP sheets is highly influenced by the orientation angle of the sheets. The orientation angle plays a key role in changing the crack pattern and hence the failure mode. The influence of CFRP sheets was adequate on increasing the flexural strength of RC beams but the ductility of the beams was reduced. The best performance was obtained when strengthening RC beam obliquely using 45˚ inclined CFRP sheets where the specimen experienced additional deflection and strength of 56% and 12% respectively and the reduction in its ductility was the least. It is recom-mended to strengthen RC beams, which are weak in flexure, using 45˚ inclined CFRP sheets.

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Improvement of Flexural Strength of RC Beams by Using the Multi-Layer Multi-Tensioning Method with CF Sheets

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.334-335.429 ◽

2007 ◽

Vol 334-335 ◽

pp. 429-432

Author(s):

Takayuki Kusaka ◽

Keiko Watanabe ◽

Ken Suke Okubo ◽

Hironori Namiki

Keyword(s):

Reinforced Concrete ◽

Carbon Fiber ◽

Flexural Strength ◽

Crack Initiation ◽

Concrete Structures ◽

Experimental Results ◽

Reinforced Concrete Structures ◽

Rc Beams ◽

Conventional Methods ◽

Energy Absorbing

A novel retrofitting method using extremely prestressed carbon fiber sheets, MLML (Multi-Layer Multi-Tensioning) method, was proposed for improving the flexural strength of reinforced concrete structures. The experimental results suggested that the crack initiation strength and the energy absorbing capacity of RC beams could be largely improved by the MLMT method. However, the advantage of the MLMT method was not so clear on the rebars yielding strength and the ultimate flexural strength of RC beams, compared with the conventional methods.

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Flexural Strength Design of Hybrid FRP-Steel Reinforced Concrete Beams

Materials ◽

10.3390/ma14216400 ◽

2021 ◽

Vol 14 (21) ◽

pp. 6400

Author(s):

Binbin Zhou ◽

Ruo-Yang Wu ◽

Yangqing Liu ◽

Xiaohui Zhang ◽

Shiping Yin

Keyword(s):

Reinforced Concrete ◽

Flexural Strength ◽

Failure Modes ◽

Reinforcement Ratio ◽

Reinforced Concrete Beams ◽

Rc Beams ◽

Strength Reduction Factor ◽

Steel Reinforced Concrete ◽

Strength Design ◽

Reinforced Beams

Through proper arranging of a hybrid combination of longitudinal fiber reinforced polymer (FRP) bars and steel bars in the tensile region of the beam, the advantages of both FRP and steel materials can be sufficiently exploited to enhance the flexural capacity and ductility of a concrete beam. In this paper, a methodology for the flexural strength design of hybrid FRP-steel reinforced concrete (RC) beams is proposed. Firstly, based on the mechanical features of reinforcement and concrete and according to the latest codified provisions of longitudinal reinforcement conditions to ensure ductility level, the design-oriented allowable ranges of reinforcement ratio corresponding to three common flexural failure modes are specified. Subsequently, the calculation approach of nominal flexural strength of hybrid FRP-steel RC beams is established following the fundamental principles of equilibrium and compatibility. In addition to the common moderately-reinforced beams, the proposed general calculation approach is also applicable to lightly-reinforced beams and heavily-reinforced beams, which are widely used but rarely studied. Furthermore, the calculation process is properly simplified and the calculation accuracy is validated by the experimental results of hybrid FRP-steel RC beams in the literature. Finally, with the ductility analysis, a novel strength reduction factor represented by net tensile steel strain and reinforcement ratio is proposed for hybrid FRP-steel RC beams.

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Effect of the plate bondstress-slip property on the flexural strength of FRP Plated RC beams using a displacement-based approach

SN Applied Sciences ◽

10.1007/s42452-020-03723-w ◽

2020 ◽

Vol 2 (11) ◽

Cited By ~ 1

Author(s):

Mohamed El-Zeadani ◽

Raizal Saifulnaz Muhammad Rashid ◽

Mugahed Yahya Hussein Amran ◽

Mohamed Ibrahem Swi

Keyword(s):

Flexural Strength ◽

Rc Beams ◽

Displacement Based

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FLEXURAL PERFORMANCE OF RC BEAMS UNDER TROPICAL CLIMATE EFFECTS

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2014.3 ◽

2014 ◽

Vol 1 (1) ◽

Author(s):

Nauwal Suki ◽

Mohd Hisbany Mohd Hashim ◽

Afidah Abu Bakar

Keyword(s):

Flexural Strength ◽

Room Temperature ◽

Tropical Climate ◽

The Other ◽

Bending Test ◽

Rc Beams ◽

Near Surface ◽

Climate Effects ◽

Flexural Performance ◽

Temperature Conditions

This study investigates the flexural performance of RC beams under the effects of a tropical climate. Effects from the tropical climate, such as heat and rain throughout the year, may cause deterioration to the surface of concrete. Concrete will gradually erode and may expose the steel inside the beam. If the steel is exposed, it may be oxidized, thus decreasing the strength of the RC structure. To avoid this situation from happening, the Near Surface Mounted (NSM) method of strengthening may be applied as an alternative. Three beams with the size of 125 mm x 300 mm x 1800 mm (width; height; length) were constructed for this study. The first one is a beam without strengthening, while the other two beams were strengthened with CFRP plate horizontally positioned on the tension zones, where one beam is placed under room temperature conditions, while the other is left to endure the conditions of the tropical climate for a period of 6 months. All three beams were then tested under a four-point bending test. Results show that the strengthened beam placed under room temperature conditions has 1% more flexural strength compared to the exposed beam. The exposed beam, however, has 21% more flexural strength compared to the control beam. Thus, NSM is proven to strengthen beams even in a tropical climate.

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