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Article

Faezeh Nejati and S.A. Edalatpanah

The purpose of this paper is to investigate the effect of steel and carbon fibers on the mechanical properties of light concrete in terms of tension strength, compressive…

Abstract

Purpose

The purpose of this paper is to investigate the effect of steel and carbon fibers on the mechanical properties of light concrete in terms of tension strength, compressive strength and elastic modulus under completely dry and wet conditions.

Design/methodology/approach

In this study, the lightweight concrete made of Light Expanded Clay Aggregate (LECA) as coarse aggregate and sand as fine aggregate was used. To achieve a compressive strength of at least 20 MPa, microsilica was used 10 percent by weight of cement. In order to compensate for the reduction of tension strength of concrete, steel and carbon fibers were used with three volume ratio of 0.5, 1 and 1.5 percent in concrete. The results of concrete specimens were studied at the age of 7, 28, 42 and 90 days under controlled dry and wet conditions.

Findings

The results showed that the addition of steel and carbon fibers to the concrete mixture would reduce the drop in slump. Also, the use of steel and carbon fibers plays a significant role in increasing the tension strength of the specimens. Furthermore, the highest increase in tension strength of steel and carbon fiber samples was 83.3 and 50 percent, respectively, than the non-fibrous specimen when evaluated at 90 days of age. Moreover, the steel and carbon fiber increased the water absorption of the samples. Adding steel and carbon fibers to a lightweight concretes mixture containing LECA aggregates plays a significant role in increasing the modulus of elasticity of the samples. The highest increase in the elastic modulus of steel and carbon fibers was 18.9 and 35.4 percent, respectively, than the non-fibrous specimen at 28 days of age.

Originality/value

In this paper, the authors investigated the mechanical properties of steel fiber and carbon reinforced concrete. Also, according to the conditions of storage of samples and the age of concrete (day), the experiments were carried out on samples.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

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Article

Wang Jiawei and Sun Quansheng

In order to reduce the impact of bridge construction on traffic under the bridge, the construction of bridges for some important traffic nodes usually adopts the swivel…

Abstract

Purpose

In order to reduce the impact of bridge construction on traffic under the bridge, the construction of bridges for some important traffic nodes usually adopts the swivel construction method. The spherical hinge is a rotating mechanism located between the bottom of the pier and the bridge cap, and is subjected to tremendous vertical pressure. According to the mechanical characteristics of the spherical hinges, this paper applies the ultra-high performance concrete (UHPC) material to the spherical hinge. The spherical hinge is subjected to a compression test to test its mechanical behavior. This paper aims to discuss this issue.

Design/methodology/approach

In order to test the mechanical behavior of the UHPC spherical hinge, multiple sets of 100 mm UHPC spherical hinge specimens were prefabricated. Through the universal testing machine to measure the compressive strength of specimens, draw the force-displacement curve to analyze the failure mechanism and establish the stress calculation formula of the spherical hinge at each point along the radial direction.

Findings

Through the test, the compressive strength of UHPC spherical hinge is obtained, and the influencing factors of UHPC spherical hinge strength are found: reducing water–cement ratio, increasing steel fiber content and length and changing steel fiber arrangement direction can effectively improve the compression strength of UHPC spherical hinge.

Originality/value

For the first time, UHPC materials were applied to the spherical hinge structure, the UHPC spherical hinge diameter is 1/3 of the diameter of the reinforced concrete spherical hinge, which is equivalent to the diameter of the steel spherical hinge. By applying the UHPC spherical hinge, the manufacturing cost is reduced, the process is simple, and the construction difficulty is reduced.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

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Article

M.F. Boseman, Y.W. Kwon, D.C. Loup and E.A. Rasmussen

In order to connect a fiberglass composite structure to a steel structure, a hybrid composite made of glass and steel fibers has been studied. The hybrid composite has one…

Abstract

Purpose

In order to connect a fiberglass composite structure to a steel structure, a hybrid composite made of glass and steel fibers has been studied. The hybrid composite has one end section with all glass fibers and the opposite end section with all steel fibers. As a result, it contains a transition section in the middle of the hybrid composite changing from glass fibers to steel fibers. The purpose of this paper is to examine interface strength at the glass to steel fiber transition section, in order to evaluate the effectiveness of the hybrid composite as a joining technique between a polymer composite structure and a metallic structure.

Design/methodology/approach

The present micromechanical study considers two types of glass to steel fiber joints: butt and overlap joints. For the butt joint, the end shape of the steel fiber is also modified to determine its effect on interface strength. The interface strength is predicted numerically based on the virtual crack closure technique to determine which joint is the strongest under various loading conditions such as tension, shear and bending. Numerical models include resin layers discretely. A virtual crack is considered inside the resin, at the resin/glass‐layer interface, and at the resin/steel‐layer interface. The crack is located at the critical regions of the joints.

Findings

Overall, the butt joint is stronger than the overlap joint regardless of loading types and directions. Furthermore, modification of an end shape of the middle fiber layers in the butt joint shifts the critical failure location.

Originality/value

The paper describes one of a few studies which investigated the interface strength of the hybrid joint made of fiberglass and steelfiber composites. This joint is important to connect a polymeric composite structure to a metallic structure without using conventional mechanical joints.

Details

Engineering Computations, vol. 29 no. 5
Type: Research Article
ISSN: 0264-4401

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Article

Shuang You, Hongguang Ji, Juanhong Liu, Chenglin Song and Wendi Tang

Macro synthetic steel fibers were incorporated into the concrete material as a toughening agent to improve the corrosion and cracking resistances of concrete in a…

Abstract

Purpose

Macro synthetic steel fibers were incorporated into the concrete material as a toughening agent to improve the corrosion and cracking resistances of concrete in a sulfate-containing service environment.

Design/methodology/approach

To study the basic mechanical properties of this system, an accelerated concrete degradation test was designed to evaluate the influence of the sulfate ions on the concrete. A three-point bending test was carried out in the laboratory to evaluate the fracture toughness. The thickness of the damaged concrete layer and changes of microstructure of the degraded concrete were monitored by using ultrasound, scanning electron microscopy and X-ray diffraction detection methods.

Findings

The results showed that compared to the performance of ordinary concrete, in an exposure environment containing sulfate ions, the structure compactness of macro synthetic steel fiber concrete was improved, degradation resistance to the sulfate solution was enhanced and the fracture resistance performance was improved significantly.

Originality/value

The thickness of the degradation layer on the macro synthetic steel fiber concrete was less than a half of that of ordinary concrete in the sulfate environment, and was generally unchanged with increase in the sulfate concentration. Through micro-structural analysis, it was confirmed that macro synthetic steel fiber improved the compactness of the concrete structure, inhibiting access of sulfate ions to the interior of the concrete and thereby reducing the degree of sulfate degradation to the concrete.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 3
Type: Research Article
ISSN: 0003-5599

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Article

George Bikakis, Nikolaos Tsigkros, Emilios Sideridis and Alexander Savaidis

The purpose of this paper is to investigate the ballistic impact response of square clamped fiber-metal laminates and monolithic plates consisting of different metal…

Abstract

Purpose

The purpose of this paper is to investigate the ballistic impact response of square clamped fiber-metal laminates and monolithic plates consisting of different metal alloys using the ANSYS LS-DYNA explicit nonlinear analysis software. The panels are subjected to central normal high velocity ballistic impact by a cylindrical projectile.

Design/methodology/approach

Using validated finite element models, the influence of the constituent metal alloy on the ballistic resistance of the fiber-metal laminates and the monolithic plates is studied. Six steel alloys are examined, namely, 304 stainless steel, 1010, 1080, 4340, A36 steel and DP 590 dual phase steel. A comparison with the response of GLAss REinforced plates is also implemented.

Findings

It is found that the ballistic limits of the panels can be substantially affected by the constituent alloy. The stainless steel based panels offer the highest ballistic resistance followed by the A36 steel based panels which in turn have higher ballistic resistance than the 2024-T3 aluminum based panels. The A36 steel based panels have higher ballistic limit than the 1010 steel based panels which in turn have higher ballistic limit than the 1080 steel based panels. The behavior of characteristic impact variables such as the impact load, the absorbed impact energy and the projectile’s displacement during the ballistic impact phenomenon is analyzed.

Originality/value

The ballistic resistance of the aforementioned steel fiber-metal laminates has not been studied previously. This study contributes to the scientific knowledge concerning the impact response of steel-based fiber-metal laminates and to the construction of impact resistant structures.

Details

International Journal of Structural Integrity, vol. 10 no. 3
Type: Research Article
ISSN: 1757-9864

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Article

S. Arivalagan

The present day world is witnessing the construction of very challenging and difficult civil engineering structures. Self-compacting concrete (SCC) offers several economic…

Abstract

The present day world is witnessing the construction of very challenging and difficult civil engineering structures. Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fiber extends its possibilities. Steel fiber acts as a bridge to retard their cracks propagation, and improve several characteristics and properties of the concrete. Therefore, an attempt has been made in this investigation to study the Flexural Behaviour of Steel Fiber Reinforced self compacting concrete incorporating silica fume in the structural elements. The self compacting concrete mixtures have a coarse aggregate replacement of 25% and 35% by weight of silica fume. Totally eight mixers are investigated in which cement content, water content, dosage of superplasticers were all constant. Slump flow time and diameter, J-Ring, V-funnel, and L-Box were performed to assess the fresh properties of the concrete. The variable in this study was percentage of volume fraction (1.0, 1.5) of steel fiber. Finally, five beams were to be casted for study, out of which one was made with conventional concrete, one with SCC (25% silica fume) and other were with SCC (25% silica fume + 1% of steel fiber, 25% silica fume + 1.5% of steel fiber) one with SCC (35% silica fume), and other were SCC (35% Silica fume + 1% of steel fiber, 35% Silica fume + 1.5% of steel fiber). Compressive strength, flexural strength of the concrete was determined for hardened concrete for 7 and 28 days. This investigation is also done to determine the increase the compressive strength by addition of silica fume by varying the percentage.

Details

World Journal of Engineering, vol. 11 no. 4
Type: Research Article
ISSN: 1708-5284

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Article

Muhd Afiq Hizami Abdullah, Mohd Zulham Affandi Mohd Zahid, Afizah Ayob and Khairunnisa Muhamad

The purpose of this study is to investigate the effect on flexural strength of fire-damaged concrete repaired with high-strength mortar (HSM).

Abstract

Purpose

The purpose of this study is to investigate the effect on flexural strength of fire-damaged concrete repaired with high-strength mortar (HSM).

Design/methodology/approach

Reinforced concrete beams with dimension of 100 mm × 100 mm × 500 mm were used in this study. Beams were then heated to 400°C and overlaid with either HSM or high-strength fiber reinforced mortar (HSFM) to measure the effectiveness of repair material. Repaired beams of different material were then tested for flexural strength. Another group of beams was also repaired and tested by the same procedure but was heated at higher temperature of 600°C.

Findings

Repair of 400°C fire-damaged samples using HSM regained 72 per cent of its original flexural strength, 100.8 per cent of its original toughness and 56.9 per cent of its original elastic stiffness. Repair of 400°C fire-damaged samples using HSFM regained 113.5 per cent of its original flexural strength, 113 per cent of its original toughness and 85.1 per cent of its original elastic stiffness. Repair of 600°C fire-damaged samples using HSM regained 18.7 per cent of its original flexural strength, 25.9 per cent of its original peak load capacity, 26.1 per cent of its original toughness and 22 per cent of its original elastic stiffness. Repair of 600°C fire-damaged samples using HSFM regained 68.4 per cent of its original flexural strength, 96.5 per cent of its original peak load capacity, 71.2 per cent of its original toughness and 52.2 per cent of its original elastic stiffness.

Research limitations/implications

This research is limited to the size of the furnace. The beam specimen is limited to 500 mm of length and overall dimensions. This dimension is not practical in actual structure, hence it may cause exaggeration of deteriorating effect of heating on reinforced concrete beam.

Practical implications

This study may promote more investigation of using HSM as repair material for fire-damaged concrete. This will lead to real-world application and practical solution for fire-damaged structure.

Social implications

The aim of this research in using HSM mostly due to the material’s high workability which will ease its application and promote quality in repair of damaged structure.

Originality/value

There is a dearth of research on using HSM as repair material for fire-damaged concrete. Some research has been carried out using mortar but at lower strength compared to this research.

Details

Journal of Structural Fire Engineering, vol. 10 no. 1
Type: Research Article
ISSN: 2040-2317

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Article

A.E. Richardson and C. Fallow

To evaluate manufacturers' claims that structural polypropylene fibres provide satisfactory crack control reinforcement and compare the findings against steel fabric used…

Abstract

Purpose

To evaluate manufacturers' claims that structural polypropylene fibres provide satisfactory crack control reinforcement and compare the findings against steel fabric used as crack control in screeds where tensile forces are likely to occur.

Design/methodology/approach

The procedure used to provide load, deflection data, toughness indices and residual strength factors was compliant with ASTM C1018‐97 and in part ASTM C78‐02 to define first crack toughness and first crack strength.

Findings

A142 steel fabric reinforcement as used in screeds was more effective in producing toughness and residual strength when directly compared with the performance of structural polypropylene fibre reinforced concrete. Where polypropylene fibre reinforced concrete did have an advantage over the steel reinforced concrete was when I20 was exceeded and the deflection and crack width was excessive. Steel fabric tended to fail and/or the screed material failed either prior to or in excess of I20, whereas the fibre reinforced concrete held together albeit at a very much reduced load transfer when compared with steel fabric.

Practical implications

If the forces to be encountered through expansion or contraction are small, then, due to the small distances between the fibres redistributing the stress and minimising the cracks within the concrete matrix, polypropylene fibres may be suitable for crack control when directly compared with A142 fabric reinforcement. The use of fibres has benefits to the floor screed companies, using screed‐laying machines as the process avoids laying steel on which the screed machine will have to operate.

Originality/value

There is a general lack of research coverage examining crack control in screed floor finishing materials.

Details

Structural Survey, vol. 24 no. 4
Type: Research Article
ISSN: 0263-080X

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Article

A.E. Richardson

Seeks to examine the bond strength of a large range of structural polypropylene fibres, as used in concrete, to determine the most effective fibre capable of transmitting…

Abstract

Purpose

Seeks to examine the bond strength of a large range of structural polypropylene fibres, as used in concrete, to determine the most effective fibre capable of transmitting load (N/mm2) between fibre and cement within the concrete matrix.

Design/methodology/approach

Following fibre selection characterised by the highest bond strength, determined from a series of pull out tests, BS flexural tests were carried out using high bond strength fibres (40 mm × 0.9 mm diameter used at 6 kg/m3) to determine whether or not structural polypropylene fibres had any effect on the ultimate flexural strength of fibre‐reinforced concrete, when compared with the plain control sample. Fibre orientation, type of rupture failure mode and post‐crack performance were examined.

Findings

Even structural fibre dispersion was found to be best achieved with the use of monofilament polypropylene fibres (19 mm × 22 micron used at 0.9 × kg/m3) in addition to the 6 kg/m3 structural fibre dose. Structural polypropylene fibres were found not to provide additional flexural strength however, they did provide post‐crack control, limiting the crack width with subsequent enhanced durability that in turn will provide lower life cycle costs.

Practical implications

In addition to increased durability the use of fibre reinforcement negates the need to place steel reinforcement bars.

Originality/value

Investigates the ambiguity in literature between claims made by different investigators regarding the effects of polypropylene fibres on compressive and flexural strengths.

Details

Structural Survey, vol. 23 no. 3
Type: Research Article
ISSN: 0263-080X

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Article

Ashok Kumar Sahani, Amiya K. Samanta and Dilip K. Singharoy

Present study focuses on scope of developing sustainable heat resistant concrete by adding steel fibre (Sf) and polypropylene fibre (PPf) along with partially replacement…

Abstract

Purpose

Present study focuses on scope of developing sustainable heat resistant concrete by adding steel fibre (Sf) and polypropylene fibre (PPf) along with partially replacement of ordinary portland cement (OPC) and natural fine aggregate with fly ash (FA) and granular blast furnace slag (GBFS). Replacement percentages of FA and GBFS were 40% and 50%, whereas Sf and PPf for fibre-added mixes were 1% by volume of concrete and 0.25% by weight of cement, respectively.

Design/methodology/approach

An experimental work had been carried out to make comparison between control mix (CM), fibre-added sustainable mix (SCMF) and fibre-added control mix (CMF) with reference to weight loss, mechanical strength (compressive, split and flexure) after exposed to room temperature (27°C) to 1000°C at the interval of 200°C for 4 h of heat curing followed by furnace cooling and then natural cooling. Furthermore, microstructural analysis was executed at 27°C, 400°C and 800°C, respectively.

Findings

Colour change and hair line cracks were started to appear at 600°C. Fibre-added control mix and sustainable mix did not exhibit any significant cracks as compared to control mix even at 1000°C. Major losses were occurred at temperature higher than 600°C, loss in compressive strength was about 70% in control mix, while 60% in fibre-added mixes. SCMF exhibited the highest retention of strength with respect to all cases of mechanical strength.

Research limitations/implications

Present study is based on the slow heating condition followed by longer duration of heat curing at target temperature.

Practical implications

Present work can be helpful for the design engineer for assessing the fire deterioration of concrete structure existing near the fire establishment such as furnace and ovens. Building fire (high temperature for short duration) might be the further scope of work.

Originality/value

Concept of incorporating pozzolanic binder and calcareous fine aggregate was adopted to take the advantage pozzolanacity and fire resistivity. To the best of author’s knowledge, there is a scope for fill the research gap in this area.

Details

Journal of Structural Fire Engineering, vol. 10 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

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