This study experimentally investigated the effect of steel fibers on the flexural behavior and ductility of high-strength concrete hollow beams. Eight square beams (four solid and four hollow) were cast with concrete containing 0%, 0.5%, 1.0%, or 1.5% steel fibers by volume. The hollow beams had a central square hole that reduced the cross-sectional area by about 28%. All beams were tested under four-point bending until failure. Test results showed that beams with steel fibers failed in flexure, while the beam without fibers failed in flexural-shear. In general, hollow beams exhibited better ductility than solid beams. Hollow beams with up to 1.0% fibers had lower cracking, yielding,
A Review Study on Effect of Steel Fibre and Marble Dust with Strength of Pave...ijtsrd
There is growing interest in the construction of concrete pavements, due to its high strength, durability, better serviceability and overall economy in the long run. The thrust nowadays is to produce thinner and green pavement sections of better quality, which can carry the heavy loads. The high strength steel fibre reinforced concrete is a concrete having compressive strength greater than 40MPa, made of hydraulic cements and containing fine and coarse aggregates; and discontinuous, unconnected, randomly distributed steel fibres. The present study aims at, developing pavement quality concrete mixtures incorporating marble dust as partial replacement of cement as well as steel fibres. The aim is to the design of slab thickness of PQC pavement using the achieved flexural strength of the concrete mixtures. In this study, the flexural, compressive and split tensile strength for pavement quality concrete mixtures for different percentage of steel fibres and replacement of cement with marble dust are reported. It is found out the maximum increase in flexure strength, compressive strength and split tensile strength is for 0% Marble Dust and 1% Steel fibre. Also it has been possible to achieve savings in cement by replacing it with marble dust and adding fibres. This study also shows that in view of the high flexural strength, high values of compressive strength and high values of split tensile strength, higher load carrying capacity and higher life expectancy, the combination of 10 to 20% marble dust replacement along with addition of 0.5 to 1% steel fibres is ideal for design of Pavement Quality Concrete (PQC). Krishan Kumar | Sumesh Jain"A Review Study on Effect of Steel Fibre and Marble Dust with Strength of Pavement Quality Concrete" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: http://www.ijtsrd.com/papers/ijtsrd151.pdf http://www.ijtsrd.com/engineering/civil-engineering/151/a-review-study-on-effect-of-steel-fibre-and-marble-dust-with-strength-of-pavement-quality-concrete/krishan-kumar
Experimental Study on Durability Characteristics of High Performance Concrete...theijes
High performance concrete (HPC) is developed gradually over the last 15 years with respect to production of concrete with higher and higher strength. To enhance the properties such as durability, strength, workability, economy has increased due to the usage of mineral admixtures in making high performance concrete. The scope of the present study is to investigate the effect of mineral admixtures and by-products towards the performance of HPC. An effort has been made to concentrate on the mineral admixture of silica fume towards their pozzolanic reaction and industrial by-product of bottom ash and steel slag towards their hydration reaction can be contributed towards their strength and durability properties. The strength characteristics such as compressive strength, tensile strength and flexural strength were investigated to find the optimum replacement of mineral admixture and by-product admixture. HPC with mineral admixture of silica fume at the replacement levels of 0%, 5%, 10%, 15% & 20% were studied at the age of 28 days and industrial by-products of bottom ash and steel slag aggregate at the replacement level of 10%, 20%, 30%, 40% & 50% were studied at the age of 28 days. There were a total of 15 mixes created with different material contents. Out of 14 were HPC mixes and 1 were conventional concrete mixes. Finally strength has enhanced with the mix of silica fume can replaced by cement with 5% and bottom ash and steel slag can replaced by fine and coarse aggregate with 10% can be achieved higher strength when compared with other percentage of mixes. The combination mixes can be classified as binary and ternary mixes. Binary mixes involved combinations of silica fume and bottom ash (SF+BA), silica fume and steel slag aggregate (SF+SSA), bottom ash and steel slag aggregate (BA+SSA) and Ternary mixes involved combination of three materials such as silica fume, bottom ash and steel slag aggregate (SF+BA+SSA) in High performance concrete. The investigation revealed that the combined use of silica fume, bottom ash and steel slag aggregate improved the mechanical properties of HPC and thus there 3 materials may use as a partial replacement material in making HPC. The durability studies such as acid resistance, salt resistance, sulphate resistance & water absorption were conducted. From the experimental investigation, it was observed that mineral admixture of silica fume and industrial by-products of bottom ash & steel slag aggregate plays a vital role in improving the strength and durability parameter itself.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
In this study, fourteen reinforced concrete beams were tested to investigate the shear behavior of lightweight fiber reinforced concrete beams. Lightweight Expanded Clay Aggregate (LECA) was used as a partial and full replacement to the normal weight aggregate. The experimental program included three lightweight concrete beams with partial replacement of aggregate, nine lightweight concrete beams with full replacement of aggregate, and two normal weight control beams. In each group one beam was cast using steel fiber concrete, one with polypropylene fiber concrete, and one without fibers. The effects of parameters such as weight of concrete, type of fibers, area of stirrups, and shear span to depth ratio (a/d) on the beams behavior are presented. The response of the tested beams is analyzed in terms of mode of failure, deflection, strain, cracking load, and ultimatecapacity. The test results are compared to those estimated from different design codes for lightweight concrete structures.
STUDY ON BEHAVIOUR OF COMPRESSION MEMBER WITH BAMBOO AS REINFORCEMENT AND COC...civej
Concrete is the most widely used construction material. Among all ingredients of concrete, aggregates form
the major portion; further there exists a challenge in attaining the structural light weight concrete utilizing
the waste. Among the natural waste coconut shells can suitably replace these natural aggregates. The
compression testing on cube and split tensile test on cylinder were performed to authenticate its feasibility.
Concrete is reinforced with steel bars to negate its weak tension carrying capacity. However, due to higher
cost and non-renewability of steel, nowadays attempts were made to provide a low-cost, sustainable
material. The feasibility for the usage of locally procured bamboo as reinforcement is tested to evaluate its
Elasticity and ultimate strength. The axial compression test on various columns were performed comparing
its axial deformation, Energy absorption capacity, ultimate load, displacement ductility and degradation in
stiffness.
A Review Study on Effect of Steel Fibre and Marble Dust with Strength of Pave...ijtsrd
There is growing interest in the construction of concrete pavements, due to its high strength, durability, better serviceability and overall economy in the long run. The thrust nowadays is to produce thinner and green pavement sections of better quality, which can carry the heavy loads. The high strength steel fibre reinforced concrete is a concrete having compressive strength greater than 40MPa, made of hydraulic cements and containing fine and coarse aggregates; and discontinuous, unconnected, randomly distributed steel fibres. The present study aims at, developing pavement quality concrete mixtures incorporating marble dust as partial replacement of cement as well as steel fibres. The aim is to the design of slab thickness of PQC pavement using the achieved flexural strength of the concrete mixtures. In this study, the flexural, compressive and split tensile strength for pavement quality concrete mixtures for different percentage of steel fibres and replacement of cement with marble dust are reported. It is found out the maximum increase in flexure strength, compressive strength and split tensile strength is for 0% Marble Dust and 1% Steel fibre. Also it has been possible to achieve savings in cement by replacing it with marble dust and adding fibres. This study also shows that in view of the high flexural strength, high values of compressive strength and high values of split tensile strength, higher load carrying capacity and higher life expectancy, the combination of 10 to 20% marble dust replacement along with addition of 0.5 to 1% steel fibres is ideal for design of Pavement Quality Concrete (PQC). Krishan Kumar | Sumesh Jain"A Review Study on Effect of Steel Fibre and Marble Dust with Strength of Pavement Quality Concrete" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: http://www.ijtsrd.com/papers/ijtsrd151.pdf http://www.ijtsrd.com/engineering/civil-engineering/151/a-review-study-on-effect-of-steel-fibre-and-marble-dust-with-strength-of-pavement-quality-concrete/krishan-kumar
Experimental Study on Durability Characteristics of High Performance Concrete...theijes
High performance concrete (HPC) is developed gradually over the last 15 years with respect to production of concrete with higher and higher strength. To enhance the properties such as durability, strength, workability, economy has increased due to the usage of mineral admixtures in making high performance concrete. The scope of the present study is to investigate the effect of mineral admixtures and by-products towards the performance of HPC. An effort has been made to concentrate on the mineral admixture of silica fume towards their pozzolanic reaction and industrial by-product of bottom ash and steel slag towards their hydration reaction can be contributed towards their strength and durability properties. The strength characteristics such as compressive strength, tensile strength and flexural strength were investigated to find the optimum replacement of mineral admixture and by-product admixture. HPC with mineral admixture of silica fume at the replacement levels of 0%, 5%, 10%, 15% & 20% were studied at the age of 28 days and industrial by-products of bottom ash and steel slag aggregate at the replacement level of 10%, 20%, 30%, 40% & 50% were studied at the age of 28 days. There were a total of 15 mixes created with different material contents. Out of 14 were HPC mixes and 1 were conventional concrete mixes. Finally strength has enhanced with the mix of silica fume can replaced by cement with 5% and bottom ash and steel slag can replaced by fine and coarse aggregate with 10% can be achieved higher strength when compared with other percentage of mixes. The combination mixes can be classified as binary and ternary mixes. Binary mixes involved combinations of silica fume and bottom ash (SF+BA), silica fume and steel slag aggregate (SF+SSA), bottom ash and steel slag aggregate (BA+SSA) and Ternary mixes involved combination of three materials such as silica fume, bottom ash and steel slag aggregate (SF+BA+SSA) in High performance concrete. The investigation revealed that the combined use of silica fume, bottom ash and steel slag aggregate improved the mechanical properties of HPC and thus there 3 materials may use as a partial replacement material in making HPC. The durability studies such as acid resistance, salt resistance, sulphate resistance & water absorption were conducted. From the experimental investigation, it was observed that mineral admixture of silica fume and industrial by-products of bottom ash & steel slag aggregate plays a vital role in improving the strength and durability parameter itself.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
In this study, fourteen reinforced concrete beams were tested to investigate the shear behavior of lightweight fiber reinforced concrete beams. Lightweight Expanded Clay Aggregate (LECA) was used as a partial and full replacement to the normal weight aggregate. The experimental program included three lightweight concrete beams with partial replacement of aggregate, nine lightweight concrete beams with full replacement of aggregate, and two normal weight control beams. In each group one beam was cast using steel fiber concrete, one with polypropylene fiber concrete, and one without fibers. The effects of parameters such as weight of concrete, type of fibers, area of stirrups, and shear span to depth ratio (a/d) on the beams behavior are presented. The response of the tested beams is analyzed in terms of mode of failure, deflection, strain, cracking load, and ultimatecapacity. The test results are compared to those estimated from different design codes for lightweight concrete structures.
STUDY ON BEHAVIOUR OF COMPRESSION MEMBER WITH BAMBOO AS REINFORCEMENT AND COC...civej
Concrete is the most widely used construction material. Among all ingredients of concrete, aggregates form
the major portion; further there exists a challenge in attaining the structural light weight concrete utilizing
the waste. Among the natural waste coconut shells can suitably replace these natural aggregates. The
compression testing on cube and split tensile test on cylinder were performed to authenticate its feasibility.
Concrete is reinforced with steel bars to negate its weak tension carrying capacity. However, due to higher
cost and non-renewability of steel, nowadays attempts were made to provide a low-cost, sustainable
material. The feasibility for the usage of locally procured bamboo as reinforcement is tested to evaluate its
Elasticity and ultimate strength. The axial compression test on various columns were performed comparing
its axial deformation, Energy absorption capacity, ultimate load, displacement ductility and degradation in
stiffness.
Review Use of Demolished Concrete in Pavement Constructionijtsrd
Recycled aggregates consist of crushed, graded inorganic particles processed from the material that have been used in the constructions and demolition debris. The target of the present thesis work is to determine the strength characteristic of recycled aggregates for the application in concrete pavement construction. The scope of the thesis is to determine and compare the compressive strength, flexural strength and sulphate resistance of concrete by using different percentages of recycled aggregates. The investigation was carried out by using workability test, compressive strength test, flexural strength test and sulphate resistance test. A total of five mixes with replacement of coarse aggregates with 0%, 10%, 20%, 30% and 40% recycled coarse aggregates were studied. The water cement ratio was kept constant at 0.38. It was observed that workability of concrete was decreased with the increase in recycled aggregates in concrete. For the strength characteristics, the results showed that the strengths of recycled aggregate concrete was comparable to the strengths of natural aggregates concrete. Munesh Kumar | Sumesh Jain"Review Use of Demolished Concrete in Pavement Construction" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-5 , August 2017, URL: http://www.ijtsrd.com/papers/ijtsrd2368.pdf http://www.ijtsrd.com/engineering/civil-engineering/2368/review-use-of-demolished-concrete-in-pavement-construction/munesh-kumar
Experimental Study of Brick Walls with Opening Strengthened During Constructi...inventionjournals
Failure of brick walls structures can be caused by structural weakness or overloading, dynamic vibrations, settlement, and in-plane and out-of-plane deformations. In addition, the appearance of openings in brick walls has an effect on the load capacity and cracking regime after construction under working load. For these reasons, there is a need for strengthening brick walls with openings during construction. In the present study, a total of five brick wall specimens having a wall dimensions (85*65) cm and thickness (10) cm with square opening (25*25) cm were tested. The brick wall specimens were divided into two groups as follows, Group one consisted of one wall with R.C lintel 35 cm length as a control wall .Group two consisted of four strengthened specimens by number of horizontal plies of steel wire mesh (one, two three and four plies) embedded into bed joint mortar. All specimens were tested under static loads in regular increments from zero up to the crack load then failure load. In addition, wall deformations have been measured by LVDT. The obtained test results show that using one ply of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 117 % from the control ultimate capacity. Using two plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 136 % from the control ultimate capacity. However, using three plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 156 % from the control ultimate capacity. In addition, using four plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 190 % from the control ultimate capacity. The results suggest that increasing number of horizontal plies of steel wire mesh into bed joint mortar increases significantly the load carrying capacity of wall. In addition, ductility has been significantly increased. Thus, it was found that strengthening with this technique is durable, economic and easy to apply.
Flexural characteristics of sfrscc and sfrnc one way slabseSAT Journals
Abstract Fibre reinforced concrete with steel fibres attracted the attention of engineers and researchers during the last five decades. In recent times self-compacting concrete has been accepted as a quality product and are widely used. A large number of studies are available with respect to several parameters viz., load deflection behavior, toughness, flexural strength, ductility, effects of beam dimensions, concrete filling sequence, flexural toughness parameters, crack control etc. of fibre Reinforced Concrete. The present study aims to study the flexural behavior of SFRSCC and SFRNC slabs with steel fibres. Keywords: Self compacting concrete1, Fibre reinforced concrete2, Steel fibre reinforce normal concrete3, Steel fibre reinforce4, Self-compacting concrete5.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
EFFECT OF CARBON LAMINATION ON THE STRENGTH OF CONCRETE STRUCTURESIAEME Publication
This work consists of preparation and testing of different structural model like cubes, Beams and Columns. They are tested for Compression test, Flexural test and Split tensile Test. The comparison between Laminated and un-laminated Structural Models was made in order to know how much strength gain after testing of these structural models, so by which the rehabilitation of any structure can be done without demolishing it with less weight to strength ratio.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Reuse of Lathe Waste Steel Scrap in Concrete PavementsIJERA Editor
These project works assess on the study of the workability and mechanical strength properties of the concrete reinforced with industrialized waste fibers or the recycled fibers. In each lathe industries wastes are available in form of steel scraps are yield by the lathe machines in process of finishing of different machines parts and dumping of these wastes in the barren soil contaminating the soil and ground water that builds an unhealthy environment. Now a day’s these steel scraps as a waste products used by innovative construction industry and also in transportation and highway industry. In addition to get sustainable progress and environmental remuneration, lathe scrap as worn-recycle fibers with concrete are likely to be used. When the steel scrap reinforced in concrete it acquire a term; fiber reinforced concrete and steel fibers in concrete defined as steel fiber reinforced concrete (SFRC).Different experimental studies are done to identify about fresh and hardened concrete properties of steel scrap fiber reinforced concrete (SSFRC) and their mechanical properties are found to be increase due to the addition of steel scrap in concrete i.e. compressive strength, flexural strength, impact strength, fatigue strength and split tensile strength were increased but up to 0.5-2% scrap content . When compared with usual concrete to SSFRC, flexural strength increases by 40% and considerable increases in tensile and compressive strength. These steel scrap also aid to improve the shrinkage reduction, cracking resistance i.e. preventing crack propagation and modulus of elasticity. The workability of fresh SSFRC are carried out by using slump test but it restricted to less scrap contents. This work focuses on the enhancement of structural strength and improvement in fatigue life of concrete pavements by reuse of scrap steel in concrete. These concrete roads with SSFRC promises an appreciably eminent design life, offer superior serviceability and minimize crack growth and corrosion. The pioneer idea of this work is the reuse of waste lathe scrap as recycled steel fibers, which provides more cost-effective and eco-friendly sustainable SFRC PAVEMENTS.
An Experimental Study on Compressive Strength of Steel Fibre Reinforced High ...IJERD Editor
Steel fiber reinforced concrete (S F R C) is a composite material developed to reduce the brittleness
of concrete and dramatically increases its ductility. Steel fiber reinforced concrete (S F R C) is used extensively
to line the tunnels and other underground structures, to increase the thickness of pavements, and to repair and
strengthen various structures. Increasing utilization of lightweight materials in structural applications is making
pumice stone a very popular raw material. More than the target means strength of M 50 concrete is achieved
with 10 percent and 20 percent replacement of natural coarse aggregate by pumice aggregate, silica fume and
with 1% & 1.5 percent of fiber. The compressive strength of pumice concrete is seen to increase with the fiber
content and reaches an optimum value at 1.5% of fiber content and afterwards it gets decreased for various
contents of pumice.
Experimental Study Compared With American Code - ConcreteFilled – Double Skin...ijceronline
Six Specimens with three different volume fractions of steel fibers are cast and tested. Experiments on circular steel tubes in – filled with steel fiber reinforced concrete (SFRC) and normal concrete have been performed to investigate the contribution of steel fibers to the load bearing capacity of Short Composite Columns . The main variable considered in the test study is the percentage of steel. Fibers added to the in –filled concrete. All the specimens were tested under axial failure state realization. This project presents the percentage Variation in the compression strengths of the 3 types of Composite members taken under Study. The results show that 1.5% SFRC in filled steel columns exhibit enhanced ultimate load carrying compression until capacity. Experimental studies compared with American code
To Study the Properties of Latex Modified Steel Fibre Reinforced Concretepaperpublications3
Abstract: This journal documents the effects of using steel fibres in Styrene Butadiene Rubber (SBR) latex modified concrete. The study was carried out to record the different properties of steel fibre reinforced latex modified concrete such as compressive strength, split tensile strength and flexural strength. Latex modified concrete is defined as Portland cement and aggregate combined at the time of mixing with polymers that are dispersed in water. This dispersion is called as latex. Polymer when used as an admixture can improve properties like higher strength and lower water permeability than the conventional concrete. Since, concrete is weak in tension, steel fibres have been added to concrete, to improve its characteristics in tension. The polymer concrete specimens with and without fibres and latex were cast and tested to watch the improvement of certain mechanical and physical properties like compressive strengths, tensile strengths, flexural strengths and workability. Styrene Butadiene Rubber Latex polymer and hooked end steel fibres have been used for our study. The percentage of steel fibre used were 0%,0.5%,0.75%,1%,1.25% at an interval of 0.25%. The fraction of steel fibre which gave the best result was taken and latex was varied in percentage 5%, 10%, 15% to obtain maximum strength. In all total 24 specimen cubes (150mm X 150 mm X 150 mm), 24 beam (500mm X 100mm X 100mm) and 24 cylinder specimens (150 mm X 300 mm) were made. The hardened properties of concrete were tested at 28th days.
EFFECT OF STEEL AND POLYPROPYLENE FIBER ON MECHANICAL PROPERTIES OF CONCRETEIAEME Publication
This experimental work describes the mechanical properties of Hybrid Fibre Reinforced concrete(HFRC).HFRC is prepared by adding any two fibres to the conventional concrete to make it a composite mixture and that derives benefits from each of the added fibre and exhibits significant response. The fibres which are used in the present experimental work is steel fibres and polypropylene fibres. Here the polypropylene fibres helps in resists initial cracks and shrinkage ,steel fibres helps in increase the strength of concrete. In present work M30 grade of concrete can be prepared according to the IS 10262:2009 reference code. these steel and polypropylene fibres are added by 50% each with different hybridization from 0% to 1.5%.For calculating strength parameters specimens are casted and cured for 28 days and tested in the lab for Compressive Test, Tensile Test, Flexural test. From the present investigation the strength parameter increases with the percentage of increase in fibre. Therefore here the hybrid ratio of 1.5% gives the more result when compared to other hybrid ratio.
Experimental study on behaviour of concrete using steel fiber as a tensile ma...KavinKumarR3
Concrete is widely used in all over the world. It gives a compression strength and when it is collaborate with the steel the tension strength is increased. Traditional reinforcement will takes time. So by using the steel fibers in the concrete it will gives the high strength and durability. The fiber will leads to compensate the weakness in the concrete. Steel fiber reinforced concrete (SFRC) is successfully used in the slabs, flooring, and even in beams. The formation has proved the high tensile strength when it added in the concrete.
Ultimate Behavior of Lightweight High Strength Concrete Filled Steel Tube (LW...IOSR Journals
Strength and ductility of concrete members can be significantly improved with lateral confinement, usually achieved by using a steel tube casing. The concrete confinement can be utilized to make bridge lighter and have longer spans. In addition, a significant portion of the load carried concrete bridge girders is the self-weight of the girders and deck. If all or part of the girder and deck can be made using high strength lightweight concretes, there is a potential for appreciable economic savings since the self-weight could be reduced by as much as 15-20%. The study described herein investigates the static nonlinear behavior of lightweight high strength concrete filled steel tube (LWHCFST) bridges up to failure. The current study had two specific goals. The first was to experimentally determine the static modulus of elasticity of confined high strength lightweight concrete mixture. The second was to develop a nonlinear finite element computer program to study the ultimate behavior of a filled tube (LWHCFST) example bridge. The nonlinear stress-strain behavior of confined high strength lightweight concrete is evaluated experimentally by the authors and is used to help establish a comparison between the ultimate behavior of the bridge using confined normal weight concrete and confined high strength lightweight concrete. The ultimate strength of the bridge is related to the occurrence of an equivalent failure mechanism. The study indicated that the use of (LWHCFST) is beneficial for extending bridge girder lengths
Review Use of Demolished Concrete in Pavement Constructionijtsrd
Recycled aggregates consist of crushed, graded inorganic particles processed from the material that have been used in the constructions and demolition debris. The target of the present thesis work is to determine the strength characteristic of recycled aggregates for the application in concrete pavement construction. The scope of the thesis is to determine and compare the compressive strength, flexural strength and sulphate resistance of concrete by using different percentages of recycled aggregates. The investigation was carried out by using workability test, compressive strength test, flexural strength test and sulphate resistance test. A total of five mixes with replacement of coarse aggregates with 0%, 10%, 20%, 30% and 40% recycled coarse aggregates were studied. The water cement ratio was kept constant at 0.38. It was observed that workability of concrete was decreased with the increase in recycled aggregates in concrete. For the strength characteristics, the results showed that the strengths of recycled aggregate concrete was comparable to the strengths of natural aggregates concrete. Munesh Kumar | Sumesh Jain"Review Use of Demolished Concrete in Pavement Construction" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-5 , August 2017, URL: http://www.ijtsrd.com/papers/ijtsrd2368.pdf http://www.ijtsrd.com/engineering/civil-engineering/2368/review-use-of-demolished-concrete-in-pavement-construction/munesh-kumar
Experimental Study of Brick Walls with Opening Strengthened During Constructi...inventionjournals
Failure of brick walls structures can be caused by structural weakness or overloading, dynamic vibrations, settlement, and in-plane and out-of-plane deformations. In addition, the appearance of openings in brick walls has an effect on the load capacity and cracking regime after construction under working load. For these reasons, there is a need for strengthening brick walls with openings during construction. In the present study, a total of five brick wall specimens having a wall dimensions (85*65) cm and thickness (10) cm with square opening (25*25) cm were tested. The brick wall specimens were divided into two groups as follows, Group one consisted of one wall with R.C lintel 35 cm length as a control wall .Group two consisted of four strengthened specimens by number of horizontal plies of steel wire mesh (one, two three and four plies) embedded into bed joint mortar. All specimens were tested under static loads in regular increments from zero up to the crack load then failure load. In addition, wall deformations have been measured by LVDT. The obtained test results show that using one ply of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 117 % from the control ultimate capacity. Using two plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 136 % from the control ultimate capacity. However, using three plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 156 % from the control ultimate capacity. In addition, using four plies of horizontal steel wire mesh embedded into bed joint mortar gives an increase in the load carrying capacity up to 190 % from the control ultimate capacity. The results suggest that increasing number of horizontal plies of steel wire mesh into bed joint mortar increases significantly the load carrying capacity of wall. In addition, ductility has been significantly increased. Thus, it was found that strengthening with this technique is durable, economic and easy to apply.
Flexural characteristics of sfrscc and sfrnc one way slabseSAT Journals
Abstract Fibre reinforced concrete with steel fibres attracted the attention of engineers and researchers during the last five decades. In recent times self-compacting concrete has been accepted as a quality product and are widely used. A large number of studies are available with respect to several parameters viz., load deflection behavior, toughness, flexural strength, ductility, effects of beam dimensions, concrete filling sequence, flexural toughness parameters, crack control etc. of fibre Reinforced Concrete. The present study aims to study the flexural behavior of SFRSCC and SFRNC slabs with steel fibres. Keywords: Self compacting concrete1, Fibre reinforced concrete2, Steel fibre reinforce normal concrete3, Steel fibre reinforce4, Self-compacting concrete5.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
EFFECT OF CARBON LAMINATION ON THE STRENGTH OF CONCRETE STRUCTURESIAEME Publication
This work consists of preparation and testing of different structural model like cubes, Beams and Columns. They are tested for Compression test, Flexural test and Split tensile Test. The comparison between Laminated and un-laminated Structural Models was made in order to know how much strength gain after testing of these structural models, so by which the rehabilitation of any structure can be done without demolishing it with less weight to strength ratio.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Reuse of Lathe Waste Steel Scrap in Concrete PavementsIJERA Editor
These project works assess on the study of the workability and mechanical strength properties of the concrete reinforced with industrialized waste fibers or the recycled fibers. In each lathe industries wastes are available in form of steel scraps are yield by the lathe machines in process of finishing of different machines parts and dumping of these wastes in the barren soil contaminating the soil and ground water that builds an unhealthy environment. Now a day’s these steel scraps as a waste products used by innovative construction industry and also in transportation and highway industry. In addition to get sustainable progress and environmental remuneration, lathe scrap as worn-recycle fibers with concrete are likely to be used. When the steel scrap reinforced in concrete it acquire a term; fiber reinforced concrete and steel fibers in concrete defined as steel fiber reinforced concrete (SFRC).Different experimental studies are done to identify about fresh and hardened concrete properties of steel scrap fiber reinforced concrete (SSFRC) and their mechanical properties are found to be increase due to the addition of steel scrap in concrete i.e. compressive strength, flexural strength, impact strength, fatigue strength and split tensile strength were increased but up to 0.5-2% scrap content . When compared with usual concrete to SSFRC, flexural strength increases by 40% and considerable increases in tensile and compressive strength. These steel scrap also aid to improve the shrinkage reduction, cracking resistance i.e. preventing crack propagation and modulus of elasticity. The workability of fresh SSFRC are carried out by using slump test but it restricted to less scrap contents. This work focuses on the enhancement of structural strength and improvement in fatigue life of concrete pavements by reuse of scrap steel in concrete. These concrete roads with SSFRC promises an appreciably eminent design life, offer superior serviceability and minimize crack growth and corrosion. The pioneer idea of this work is the reuse of waste lathe scrap as recycled steel fibers, which provides more cost-effective and eco-friendly sustainable SFRC PAVEMENTS.
An Experimental Study on Compressive Strength of Steel Fibre Reinforced High ...IJERD Editor
Steel fiber reinforced concrete (S F R C) is a composite material developed to reduce the brittleness
of concrete and dramatically increases its ductility. Steel fiber reinforced concrete (S F R C) is used extensively
to line the tunnels and other underground structures, to increase the thickness of pavements, and to repair and
strengthen various structures. Increasing utilization of lightweight materials in structural applications is making
pumice stone a very popular raw material. More than the target means strength of M 50 concrete is achieved
with 10 percent and 20 percent replacement of natural coarse aggregate by pumice aggregate, silica fume and
with 1% & 1.5 percent of fiber. The compressive strength of pumice concrete is seen to increase with the fiber
content and reaches an optimum value at 1.5% of fiber content and afterwards it gets decreased for various
contents of pumice.
Experimental Study Compared With American Code - ConcreteFilled – Double Skin...ijceronline
Six Specimens with three different volume fractions of steel fibers are cast and tested. Experiments on circular steel tubes in – filled with steel fiber reinforced concrete (SFRC) and normal concrete have been performed to investigate the contribution of steel fibers to the load bearing capacity of Short Composite Columns . The main variable considered in the test study is the percentage of steel. Fibers added to the in –filled concrete. All the specimens were tested under axial failure state realization. This project presents the percentage Variation in the compression strengths of the 3 types of Composite members taken under Study. The results show that 1.5% SFRC in filled steel columns exhibit enhanced ultimate load carrying compression until capacity. Experimental studies compared with American code
To Study the Properties of Latex Modified Steel Fibre Reinforced Concretepaperpublications3
Abstract: This journal documents the effects of using steel fibres in Styrene Butadiene Rubber (SBR) latex modified concrete. The study was carried out to record the different properties of steel fibre reinforced latex modified concrete such as compressive strength, split tensile strength and flexural strength. Latex modified concrete is defined as Portland cement and aggregate combined at the time of mixing with polymers that are dispersed in water. This dispersion is called as latex. Polymer when used as an admixture can improve properties like higher strength and lower water permeability than the conventional concrete. Since, concrete is weak in tension, steel fibres have been added to concrete, to improve its characteristics in tension. The polymer concrete specimens with and without fibres and latex were cast and tested to watch the improvement of certain mechanical and physical properties like compressive strengths, tensile strengths, flexural strengths and workability. Styrene Butadiene Rubber Latex polymer and hooked end steel fibres have been used for our study. The percentage of steel fibre used were 0%,0.5%,0.75%,1%,1.25% at an interval of 0.25%. The fraction of steel fibre which gave the best result was taken and latex was varied in percentage 5%, 10%, 15% to obtain maximum strength. In all total 24 specimen cubes (150mm X 150 mm X 150 mm), 24 beam (500mm X 100mm X 100mm) and 24 cylinder specimens (150 mm X 300 mm) were made. The hardened properties of concrete were tested at 28th days.
EFFECT OF STEEL AND POLYPROPYLENE FIBER ON MECHANICAL PROPERTIES OF CONCRETEIAEME Publication
This experimental work describes the mechanical properties of Hybrid Fibre Reinforced concrete(HFRC).HFRC is prepared by adding any two fibres to the conventional concrete to make it a composite mixture and that derives benefits from each of the added fibre and exhibits significant response. The fibres which are used in the present experimental work is steel fibres and polypropylene fibres. Here the polypropylene fibres helps in resists initial cracks and shrinkage ,steel fibres helps in increase the strength of concrete. In present work M30 grade of concrete can be prepared according to the IS 10262:2009 reference code. these steel and polypropylene fibres are added by 50% each with different hybridization from 0% to 1.5%.For calculating strength parameters specimens are casted and cured for 28 days and tested in the lab for Compressive Test, Tensile Test, Flexural test. From the present investigation the strength parameter increases with the percentage of increase in fibre. Therefore here the hybrid ratio of 1.5% gives the more result when compared to other hybrid ratio.
Experimental study on behaviour of concrete using steel fiber as a tensile ma...KavinKumarR3
Concrete is widely used in all over the world. It gives a compression strength and when it is collaborate with the steel the tension strength is increased. Traditional reinforcement will takes time. So by using the steel fibers in the concrete it will gives the high strength and durability. The fiber will leads to compensate the weakness in the concrete. Steel fiber reinforced concrete (SFRC) is successfully used in the slabs, flooring, and even in beams. The formation has proved the high tensile strength when it added in the concrete.
Ultimate Behavior of Lightweight High Strength Concrete Filled Steel Tube (LW...IOSR Journals
Strength and ductility of concrete members can be significantly improved with lateral confinement, usually achieved by using a steel tube casing. The concrete confinement can be utilized to make bridge lighter and have longer spans. In addition, a significant portion of the load carried concrete bridge girders is the self-weight of the girders and deck. If all or part of the girder and deck can be made using high strength lightweight concretes, there is a potential for appreciable economic savings since the self-weight could be reduced by as much as 15-20%. The study described herein investigates the static nonlinear behavior of lightweight high strength concrete filled steel tube (LWHCFST) bridges up to failure. The current study had two specific goals. The first was to experimentally determine the static modulus of elasticity of confined high strength lightweight concrete mixture. The second was to develop a nonlinear finite element computer program to study the ultimate behavior of a filled tube (LWHCFST) example bridge. The nonlinear stress-strain behavior of confined high strength lightweight concrete is evaluated experimentally by the authors and is used to help establish a comparison between the ultimate behavior of the bridge using confined normal weight concrete and confined high strength lightweight concrete. The ultimate strength of the bridge is related to the occurrence of an equivalent failure mechanism. The study indicated that the use of (LWHCFST) is beneficial for extending bridge girder lengths
Performance of Beam Incorporating with Locally Available ReinforcementQUESTJOURNAL
ABSTRACT : This study comparatively evaluated the flexural performance and deformation characteristics of concrete beams reinforced with bamboo, cane and the twisted steel rebar. The yield strength (YS), ultimate tensile strength (UTS) and the elongation of nine specimens of the three materials were determined using a universal testing machine. Nine beams of concrete strength 22 MPa at age 28 days were constructed separately reinforced with steel, bamboo, and cane bars, while the stirrups were steel bars. The beams were subjected to centre-point flexural loading according to ASTM C0293 to evaluate the flexural strength. The tensile strength of bamboo and rattan bars was 43% and 13% of that of steel in the same order. The elongation of bamboo, rattan and steel were 11.5%, 14% and 15.7% respectively. The experimental flexural strength of bamboo and cane reinforced concrete beams was 34% and 26% respectively of the conventional steel RC beams. The remarkable gap between the flexural capacities of the natural rebar and that of steel can be traced not only to the tensile strength but also the weak bonding at the bar-concrete interface. It can be concluded that the bamboo bars are suitable rebar for non-load bearing and lightweight RC flexural structures, while more pre-strengthening treatment is required more importantly for rattan for improved interfacial bonding and load-carrying capacity.
This paper presents a study on flexural behaviour of concrete filled steel tube based on the former
work carried out by Manojkumar. An ANSYS model is developed that can predict the behaviour of concrete
filled steel tube to determine moment carrying capacity at ultimate point for beam Concrete filled steel tube
beams are studied and verified by the finite element program ANSYS against experimental data. The Main
parameters affecting the behaviour and strength of concrete filled beams are geometrical parameters, material
nonlinearities, loading, boundary conditions and degree of concrete confinement. To account for all these
properties ANSYS model is developed. The main parameters varied in analysis study are D/t ratio,
characteristic strength of infilled concrete. The proposed model predicts ultimate moment capacity for CFT
beams. In the numerical analysis, circular and rectangular CFT cross sections are considered using different
grades of concrete. The predicted values are compared with experimental results. Numerical analysis has
shown that for rectangular CFT’s a good confining effect can be provided. Moment capacity results obtained
from the ANSYS model are compared with the values predicted by Lin Han (2004) and different codes such as
AISC-LRFD (1999) and EC4 (1994).
A Study on Effect of Sizes of aggregates on Steel Fiber Reinforced ConcreteIJERD Editor
Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and
little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of
multidirectional and closely spaced reinforcement, which can be provided in the form of randomly distributed
fibers. Steel fiber is one of the most commonly used fibers The present experimental study considers the effect
of aggregate size and steel fibers on the modulus of elasticity of concrete. Crimped steel fibers at volume
fraction of 0%.0.5%, 1.0% and 1.5% were used. Study on effect of volume fraction of fibers and change of
aggregate size on the modulus of elasticity of concrete was also deemed as an important part of present
experimental investigation. This work aims in studying the mechanical behavior of concrete in terms of modulus
of elasticity with the change of aggregate size reinforced with steel fibers of different series for M30 and M50
grade concretes. The results obtained show that the addition of steel fiber improves the modulus of elasticity of
concrete. It was also analyzed that by increasing the fiber volume fraction from 0%, to 1.5% there was a healthy
effect on modulus of elasticity of Steel Fiber Reinforced concrete.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Study on Strength Properties of Concrete with Partial Replacement of Fine Agg...IJERDJOURNAL
Abstract: One of the major challenges in our present society is the protection of environment. Some of the important elements in this respect are the reduction in the consumption of energy and natural raw materials and consumption of waste materials must be increased. This experimental study is to investigate the effect of using copper slag as a replacement of fine aggregate on the strength properties. The common management options for copper slag are recycling, recovering of metal, production of value added products such as abrasive tools, roofing granules, cutting tools, abrasive tiles, glass, rail road ballast, asphalt pavements. Despite increasing reusing of copper slag, the huge amounts of its annual production is disposed in dumps or stockpiles. In the present study experimental investigation has been carried out on M25 grade concrete is used and tests were conducted for various percentage replacement of fine aggregate with copper slag in concrete. The obtained results were compared with those of control concrete made with ordinary portland cement and sand. The use of copper slag in concrete provides potential environment as well as economic benefits for all related industries, particularly in areas where a considerable amount of copper slag is produced. This study reviews the characteristics of copper slag and its effect on the engineering properties of M25 grade concrete.
State of The Art Report on Steel-Concrete In filled Composite ColumnIJERA Editor
Steel-concrete composite systems for buildings are composed of concrete components that interact with
structural steel components within the same system. By their integral behavior, these components give the
required attributes of strength, stiffness and stability to the overall system. Composite members, as individual
elements of a system, have been in use for a considerable number of years. They consist of composite columns
or trusses, encased or filled composite columns, and steel deck reinforced composite slabs. In this paper, a
review of the research carried out on composite columns with infills is given with emphasis on experimental
work.
A REVIEW ON STRENGTHENING OF REINFORCED CONCRETE BEAMS USING GLASS FIBER REIN...Ijripublishers Ijri
Worldwide, a great deal of research is currently being conducted concerning the use of fiber reinforced plastic wraps,
laminates and sheets in the repair and strengthening of reinforced concrete members. Fiber-reinforced polymer (FRP)
application is a very effective way to repair and strengthen structures that have become structurally weak over their life
span. FRP repair systems provide an economically viable alternative to traditional repair systems and materials.
Experimental investigations on the flexural and shear behavior of RC beams strengthened using continuous glass fiber
reinforced polymer (GFRP) sheets are carried out. Externally reinforced concrete beams with epoxy-bonded GFRP sheets
were tested to failure using a symmetrical two point concentrated static loading system. Two sets of beams were casted
for this experimental test program. In SET I three beams weak in flexure were casted, out of which one is controlled
beam and other two beams were strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in flexure.
In SET II three beams weak in shear were casted, out of which one is the controlled beam and other two beams were
strengthened using continuous glass fiber reinforced polymer (GFRP) sheets in shear. The strengthening of the beams
is done with different amount and configuration of GFRP sheets.
dding fibers to concrete helps enhance its tensile strength and ductility. Synthetic fibres
are preferable to steel ones which suffer from corrosion that reduces their functionality with time.
More consideration is given to synthetic fibres as they can be sourced from waste plastics and their
incorporation in concrete is considered a new recycling pathway
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
2. the flexural performance of unreinforced [7–11] and rein-
forced [12–23] concrete beams.
One of the serious disadvantages of reinforced concrete
is the heavy weight of such a type of construction material.
Consequently, more loads and thus more bearing stresses
are transferred to the soil, which urges the use of larger and
may be deeper foundations. As a result, the cost would be
increased. Several solutions were proposed by researchers
to reduce the effect of concrete heavy weight. Among these
solutions to reduce the weight of the structure are the use
of lightweight aggregates and the use of composite ma-
terials and structures, and the use of recycled aggregates
was suggested to reduce the construction cost [24, 25]. The
use of optimized structural sections can also be considered
as a candidate solution. Hollow sections are types of op-
timized structural sections that reduce the cross-sectional
size of structural members, leading to a reduced weight
and lower consumption of concrete materials. Thus,
compared with solid sections, hollow ones can be con-
sidered lighter and more economical. Although the re-
duction in section means lower moment of inertia, which
may lead to lower strength and higher deformations, the
use of steel fibers is known to increase the flexural strength
and enhance the flexural behavior of reinforced concrete
beams. Hence, this positive contribution may substitute
the reduction in strength and performance resulting from
the reduction of the section size of hollow beams compared
with solid ones.
Few experimental research studies were found in the
literature on the flexural behavior of reinforced beams with
longitudinal holes [26–28]. Altun et al. [26] tried to
evaluate the flexural behavior of box steel fiber-reinforced
concrete beams. Normal strength concrete of 22 MPa
compressive strength and 60 mm length steel fibers with a
maximum dosage of 60 kg/m3
(0.77% Vf ) were used. They
showed that a 44% reduction in weight can be obtained but
with a 29% lower load carrying capacity. Murugesan and
Narayanan [27, 28] experimentally investigated the flex-
ural behavior of reinforced concrete beams having a small-
sized longitudinal circular hole (5% of cross-sectional
area). They showed that the load carrying capacity of
hollow beams reduces as the hole size increases and it was
in general lower than that of solid beams. Moreover, they
observed that the deflection increases as the hole size
increases.
The previous review shows that hollow beams can be
considered as a candidate solution to reduce the weight of
the structure and to provide a more environment-friendly
solution. However, research works to evaluate the flexural
behavior of hollow beams are very limited in the literature.
Moreover, the beams of the few research studies found in the
literature were either reinforced with limited amount of steel
fiber or have no fibers and were all made of moderately low
compressive strength concrete. Trying to fill some gaps of
knowledge about this issue, in this study, an experimental
work was directed toward investigating the flexural per-
formance of high-strength steel fiber-reinforced hollow
concrete beams. For this purpose, a square central longi-
tudinal hole was used to reduce the cross-sectional area by
approximately 28% and steel fiber contents up to 117 kg/m3
were incorporated in the concrete mixtures.
2. Experimental Work
2.1. Concrete Mixture and Material Properties. Solid and
hollow beams with high strength concrete and reinforced
with steel fibers and conventional steel bars were produced
to conduct the experimental work of this study. A previously
used high-strength concrete mixture was adopted [29] to
achieve a 28-day cylinder compressive strength (fc
′) of
60 MPa. Table 1 lists the details of the adopted mixture, in
which the proportions of all materials were fixed except the
dosage of steel fiber. In this study, cold drawn glued hooked-
end steel fibers were adopted with three volumetric contents
of 0.5, 1.0, and 1.5%. The use of high steel fiber Vf (more than
1.5%) decreases the workability and increases the oppor-
tunity of fiber balling in the presence of aggregate (sand and
gravel), which results in lower compressive strength.
Therefore, a 1.5% hooked-end steel fiber was suggested as an
effective and economical volume fraction [30]. Katzer et al.
[31, 32] clearly indicated that hooked-end steel fiber is the
most popular and effective type of reinforcing fiber for
concrete. The diameter, length, and aspect ratio of the used
steel fiber were 0.55 mm, 30 mm, and 55, respectively,
wheras its density and tensile strength were 7800 kg/m3
and
1500 MPa, respectively. Crushed stone with a maximum
diameter of 10 mm was used as coarse aggregate. Natural
sand was used as fine aggregate. More details about the used
materials are listed in a previous work [29]. The used cement
was Portland cement type 42.5R, whereas silica fume was used
as partial cement replacement. The use of silica fume is known
to positively affect the mechanical properties of concrete
because of its effective reaction with the cement components
[33–35]. To assure an acceptable workability, the high range
water reducer Master Glenium 51 was used in all mixtures.
Twenty-four hours after concrete casting, the beams and
control specimens were removed from their molds and cured
in temperature-controlled water tanks for 28 days.
2.2. Control Tests. Three control tests were adopted to
evaluate the strength and elasticity of the prepared concrete
mixtures. The concrete compressive strength, splitting
tensile strength, and modulus of elasticity were evaluated
using 100 × 200 mm cylinders in accordance with ASTM
C39, ASTM C496, and ASTM C469, respectively. In addition
to the abovementioned three control tests, three-point
flexural tests were conducted using 100 ×100 × 500 mm
concrete beams. According to RILEM FMC-50, the beams
were notched at the centerline of the bottom surface to
perform the fracture energy test [36], yet the test span was
different. The notch depth was 40 mm, whereas the test span
was 400 mm for all tested beams. The flexural tests were
conducted using an electromechanical closed-loop servo-
controlled universal testing machine from INSTRON with a
capacity of 250 kN. The test setup and the details of the test
specimens are shown in Figure 1. The performed tests were
displacement controlled at a rate of 0.2 mm/min.
2 Advances in Civil Engineering
3. 2.3. Hollow Reinforced Concrete Beams. To investigate the
effect of sectional hollowing on the flexural performance of
steel fiber-reinforced beams, a total of 8 beams were cast. All
beams have a square cross section with a side length of
150 mm and a beam length of 850 mm. The flexural tests of
all beams were conducted under four-point loading with a
span of 750 mm where the midspan deflection was measured
using one linear variable differential transformer (LVDT), as
shown in Figure 2. From the literature [37], it was observed
that an a/d ratio of 2.5 resulted in the lowest flexural ca-
pacity, whereas the highest flexural capacity was attained
with an a/d ratio of 1.5. In this research, all beams were
tested using the same test configuration and with a fixed
shear arm to effective depth ratio (a/d) of 2.0. Thus, the effect
of a/d was kept constant, where for beams with the same
materials and dimensions but with different a/d values, the
flexural strength and behavior varied considerably.
Table 1: Details of concrete mixtures [29].
Mix
code
Steel fiber
Cement
(kg/m3
)
Coarse
aggregate
(kg/m3
)
Sand
(kg/m3
)
Silica
fume
(kg/m3
)
HRWR
(kg/m3
)
W/C
Slump
(mm)
Vf% kg/m3
B0.0 — —
465 680 1170 35
6.6
0.43
105
B0.5 0.5 39.3 6.7 77
B1.0 1.0 78.5 6.7 69
B1.5 1.5 117.8 6.8 63
(a)
40mm
L1 = 400mm
200mm
b = 100mm
h = 100mm
60mm
Initial notch
length (a)
40mm
Applied load
(a)
(a)
Section (a-a)
(b)
Figure 1: Specimen geometry and test setup for fracture energy.
Load Cell
LVDT at midspan
LVDT at 12.5cm
from midspan
Figure 2: Test setup of the solid and hollow beams.
Advances in Civil Engineering 3
4. The experimental program was directed toward in-
vestigating the effect of cross-sectional hollowing and the
dosage of the steel fiber. The hole of hollow beams was
square with its center coinciding with the center of the beam
cross section. Thus, the thicknesses of the top, bottom, and
side walls were equal. The hollow beams were manufactured
with a hole side length of 80 mm; thus, the wall thickness was
35 mm. As a result, the cross-sectional area of the hollow
beams was 28.4% less than that of solid beams. All beams
were reinforced with 8 mm steel reinforcing bars, as shown
in Figure 3. It is clear that the wall thickness is slightly larger
than the steel fiber length, which has less preferential fiber
alignment compared to solid beams [38–40]. Such size may
also lead to concrete casting difficulties. Therefore, the
concrete was carefully cast in the mold in stages. Firstly, the
bottom flange was poured with external vibration, and then
the remaining walls were cast. The tested beams were divided
into two groups. The first group consisted of four solid
beams (S) with different fiber contents of 0, 0.5, 1.0, and
1.5%, whereas the second group consisted of four hollow
beams (H) with the same sequence of fiber contents. The
beam identification number starts with letters S or H, fol-
lowed by the fiber content. Thus, the identification number
of a hollow beam with 1.5% fiber content becomes H-1.5 and
so on. All beams were cast with a fixed number of stirrups to
assure flexural failure. Figure 3 shows the geometry and
reinforcing details of the beams tested in this study.
3. Results of Control Tests
The test results of the control cylinders show that inclusion
of 1.0 and 1.5% of steel fiber resulted in obvious enhance-
ment in compressive strength, whereas the 0.5% steel fiber
content was ineffective. From the comparison between the
compressive strengths of the 1.0% and 1.5% steel fiber, it is
obvious that both fiber contents resulted in almost identical
strength values. The percentage increase of compressive
strength was approximately 16% for fiber contents of 1.0 and
1.5%. For the same contents of steel fibers, Song and Hwang
[2] reported an increase of 15%, which agrees well with the
results of the current research. Abbass et al. [5] reported a
maximum development of 8%, which is consistent with the
results obtained by Thomas and Ramaswamy [3] for cube
and cylinder specimens (2.6% to 8.3%) for 1.5% fiber
content. On the other hand, other researchers [11, 26] re-
ported insignificant drop or increase in compressive
strength of steel fiber reinforced concrete (SFRC). Table 2
summarizes the experimental results of the mechanical
properties of the controlling mixes.
The test results also showed that the splitting tensile
strength increases with the increase in fiber content, which is
frequent in the literature [41–44]. The increase in splitting
tensile strength can easily be attributed to the fiber bridging
potential of tensile cracks. Comparing the results, it is ob-
vious that the splitting tensile strength increased by ap-
proximately 30% when only 0.5% steel fiber was included,
whereas this increase jumped to approximately 52% for fiber
content of 1.0% and 57% for fiber content of 1.5%. Ashour
et al. [14] reported that, for concrete with 79 MPa
compressive strength and 1.0% steel fiber content, the
splitting tensile strength increased by 52%, which completely
agrees with the current results, whereas Thomas and
Ramaswamy [3] reported an increase of 41% for a similar
concrete grade. On the other hand, it was found out that
there is no clear trend for the results of the modulus of
elasticity, which reveals that the inclusion of steel fiber is not
so effective (Table 2).
4. Results of Fracture Energy Test
The fracture energy (GF) of a prism tested under flexure can be
defined as the energy required to crack a unit area, which is
determined from the load-deflection curve of the tested prism.
In the current investigation, the fracture test recommended by
RILEM FMC-50 [36] was adopted. From the three-point
flexural test and using the central deflection, in addition to
mass and geometry, of the tested prism, the following
equation was used to calculate the fracture energy GF:
GF �
W0 + m × g × L1/L × δf
b × (h − a)
, (1)
where the prism geometrical parameters b, h, a, and L1 are
shown in Figure 1, L is the length of the specimen, m is the
specimen mass, g is the gravity acceleration, and δf is the
central displacement (deflection) at failure.
Considering the modulus of elasticity of concrete Ec and
its tensile strength ft and to evaluate the brittleness of
concrete using the tested specimens, Equation (2) is used to
evaluate the characteristic length Lch. This length can be used
as an index of the brittleness of the tested specimen, where
the higher the characteristic length, the lower the brittleness
and the much ductile the tested prism is:
S H
80mm
∅6.3/100
2∅8
150mm
2∅8
150mm
Figure 3: Sectional geometry and reinforcing details of the solid
and hollow beams.
Table 2: Fiber volume fraction and control test results of the four
mixtures.
Mix code
Vf fc
′ fsp E
% kg MPa MPa GPa
B0 0.0 0 63.3 4.2 36.04
B0.5 0.5 39.2 61.7 5.4 35.79
B1.0 1.0 78.5 73.3 6.4 37.70
B1.5 1.5 117.7 73.4 6.6 36.78
4 Advances in Civil Engineering
5. Lch �
Ec GF
ft2
. (2)
Based on the experimental results obtained from the
control cylinders of splitting tensile strength and modulus of
elasticity, the fracture energy GF and the characteristic length
Lch were calculated for each of the four mixtures associated
to the four fiber contents. These calculated results are il-
lustrated in Figure 4.
Figure 4(a) explicitly shows that the fracture energy of
the used mixture jumped as 0.5% steel fiber was included,
which was 23 times that of the plain specimen. On the other
hand, Lch showed significant increase from 256 to 3487 when
only 0.5% steel fiber was added to the same mixture as shown
in Figure 4(b). The two measurements reflect the significant
contribution of the low amount of steel fiber to control
brittleness and increase ductility of the tested concrete
prisms. The inclusion of 1.0% steel fiber is shown to double
the fracture energy compared with the specimens with 0.5%,
whereas an extra increase in Lch, by approximately 50%, was
gained as the fiber content was increased from 0.5% to 1.0%.
This result agrees with results obtained by previous re-
searchers [8, 11]. The inclusion of 1.5% steel led to further
increase in the ductility; however, the gain over the 1.0%
prisms was approximately 18% in terms of fracture energy
and approximately 7% in terms of Lch.
The flexural test curves of the tested prisms with the four
different fiber contents are shown in Figures 5 and 6. The
load-displacement curves of the tested prisms are shown in
Figure 5, whereas Figure 6 presents the relationship between
load and the crack mouth opening displacement (CMOD).
Figure 6 explicitly shows that the inclusion of steel fibers
significantly enhanced the flexural performance of the tested
prisms. It also shows that the load carrying capacity was
higher for fibrous prisms than those without fiber. More-
over, the load-displacement behavior beyond the first crack
was significantly improved by fiber inclusion. The figure also
presents the strain-hardening behavior of the specimens
with a high fiber content of 1.5% until a 2 mm displacement,
after which the load capacity showed continuous decrease.
On the other hand, the 1.0% fiber content specimens could
withstand strain hardening up to approximately 1 mm,
beyond which significant load drop was recorded. Such
behavior was not noticed for the specimens containing no
fiber or 0.5% fiber. Instead, the load carrying capacity
dropped directly after cracking, showing significant de-
flections and CMOD for lower values of load, as shown in
Figures 5 and 6. Similar results were also obtained in pre-
vious research [8, 11, 19]. This again reveals the significant
contribution of steel fibers in changing the flexural behavior
from brittle to more ductile.
The strain hardening of prisms with 1.0% and 1.5% fibers
can be attributed to the behavior of the fibers during crack
bridging. The close examination of the fracture surface along
the crack shows that most fibers along the fracture surface of
those prisms were pulled out of the matrix. The higher
quantity of fibers led to better distribution of stresses on
fibers during the crack bridging, which resulted in higher
load capacity with uniform displacement and crack opening
until they were pulled out. On the other hand, for the prisms
with 0.5% fiber, instead of being pulled out of the concrete
matrix, most fibers were broken, which is attributed to the
high fiber stresses due to the low number of fibers bridging
the crack. Figure 7 shows close examination of the fracture
surfaces of the four tested prisms.
5. Test Results of the Reinforced Solid and
Hollow Beams
In this section, the flexural behavior of the solid and hollow
reinforced concrete beams is discussed. The discussion fo-
cuses mostly on the effect of cross-sectional hollowing and
fiber content on the cracking and failure type, load-
displacement behavior, and ductility of the tested beams.
5.1. Cracking and Failure Behavior. In general, beams with
steel fiber exhibited better behavior than those without fiber.
All solid fibrous beams failed in flexure, whereas those
without fiber exhibited less ductile behavior and failed in
flexural-shear cracking. The nominal flexural capacity (Mn) of
the SFRC beam is the resultant from the contributions of both
reinforcing bars (m1) and the residual tensile strength pro-
duced from fiber bridging (m2). The ACI 544 [44] proposed
the following equation for the calculation of the flexural
capacity of singly reinforced fibrous concrete solid beams:
Mn � m1 + m2, (3)
where
m1 � As fs d −
a
2
, (4)
m2 � σtb(h − e)
h
2
+
e
2
−
a
2
. (5)
The above equations were derived from the stress and
strain distributions along the depth of the cross section, as
shown in Figure 8.
The behavior of hollow fibrous beams was superior to
their corresponding beams without fiber, where the fibrous
beams failed in pure flexure, whereas the hollow beams
without fibers showed flexural and flexural-shear cracking at
failure. Based on the ACI 544-proposed equation, the re-
duction in the flexural capacity of the hollow beams due to
the reduction in their cross-sectional area leads to modifying
of Equation (5) to the following equation:
m2,modified � σt b(h − e) − b′ × h′
h
2
+
e
2
−
a
2
, (6)
where b, h, and d are the beam cross-sectional dimensions, b′
and h′ are the hole dimensions, and e is the distance from the
top of the tensile stress block to the upper fiber of the beam,
which can be obtained through the strain constitutive relation
e � εf + 0.003
C
0.003
, (7)
If a is the depth of the rectangular stress block of the hollow
section, then
Advances in Civil Engineering 5
6. a �
Asfs + σthb − σtb′h′
0.85fc
′b + 512.82εf σtb + 1.538σtb
,
σt � 0.00772
lf
df
Vf Fbe,
(8)
where σt is the tensile stress of the fibrous concrete, which is
calculated based on the effect of three parameters: the fiber
aspect ratio lf/df, the fiber volume fraction (Vf ), and the bond
between the matrix and the fibers in terms of bond efficiency
factor (Fbe), which is ranging between 1 and 1.2. For the
hooked-end steel fiber, Fbe equals 1.2.
Table 3 summarizes the calculated load capacity based on
Equation (3). It shows that the differences between the ul-
timate loads obtained from the experimental work and the
predicted ultimate loads based on ACI 544 are decreasing
when increasing the fiber Vf to 6% for 1.5% Vf. On the other
hand, these differences are increasing with the increase of Vf
for the hollow beams.
Figure 9 shows a cracked beam under bending test. All
beams failed by the crushing of the compression concrete
after steel yielding and tension crack propagation. As shown
in Figure 10, for solid and hollow fibrous beams, flexural
vertical cracks were first initiated within the pure moment
zone as the applied load reached the cracking load. As the
load increased, these crackspropagated and new cracks
initiated. The firstly initiated cracks kept propagating until
the yielding of the steel reinforcement. After reaching the
peak load, compression crushing started to appear in the
compression zone of some beams as the load was dropping.
In addition to the flexural cracks, flexural-shear cracks
0
10
20
30
40
50
60
0
2
4
6
8
10
0 0.5 1 1.5
G
F,fiber/
G
F,no
fiber
Fracture
energy
G
F
(N/mm)
Vf (%)
GF (N/mm)
GF,fiber/GF,no fiber
(a)
L
ch,fiber/
L
ch,no
fiber
Vf (%)
Lch (mm)
Lch,fiber/Lch,no fiber
0
5
10
15
20
25
0
2
4
6
Characteristic
length
L
ch
(mm)
8
10
0 0.5 1 1.5
103
x
(b)
Figure 4: Experimental results of (a) fracture energy GF and (b) characteristic length Lch.
0
1
2
3
4
5
0 5 10 15 20
Load
(kN)
Displacement (mm)
B0.0
B0.5
B1.0
B1.5
0
1
2
3
4
5
0 0.5 1
Load
(kN)
Displacement (mm)
Figure 5: Load-displacement curves of the tested prisms.
0
1
2
3
4
5
0 5 10 15 20 25
Load
(kN)
CMOD (mm)
B0.0
B0.5
B1.0
B1.5
0
1
2
3
4
5
0 0.5 1
Load
(kN)
CMOD (mm)
Figure 6: Load-CMOD curves of the tested prisms.
6 Advances in Civil Engineering
7. developed in the beams containing no fibers (S-0 and H-0), as
shown in Figure 10. The failure of these two beams was due to
the propagation of these cracks outside within the shear span.
5.2. Load-Displacement Curves. Figure 11(a) compares the
load-deflection curves of the four solid beams. It is clear in
the figure that the yielding load increases as the fiber content
increases. The yielding load of the solid beams S-0, S-0.5,
S-1.0, and S-1.5 with fiber contents 0, 0.5, 1.0, and 1.5% were
55.4, 57.1, 60.7, and 64.8 kN, respectively. It was also ob-
served that the higher the fiber content, the higher the first
cracking load, which reflects the higher potential of fiber
reinforced beams to resist the flexural stresses because of the
fiber bridging action. The cracking load of the solid beams
with fiber contents of 0, 0.5, 1.0, and 1.5% were 21.9, 28.1,
29.5, and 32.7 kN, respectively. The figure also shows that the
deflection at steel yielding was less for fibrous beams, which
reflects the higher elastic stiffness of steel fiber beams
h
b
e
a/2
εs(f’ibers)
εs(bars)
εc = 0.003
C
Neutral
axis
σt
Tfc
Trb
c a
0.85f′
c
d
Figure 8: Typical stress and strain distribution in SFRC beams, according to ACI 544.
Table 3: Experimental and predicted results of ultimate load capacity.
Beam ID h′ (mm) b′ (mm) Vf (%) Pu_exp·(kN) Pu_ACI544·(kN) Pu_exp/Pu_ACI544
S-0 0 0 0.0 68.04 54.70 1.24
S-0.5 0 0 0.5 68.92 57.73 1.19
S-1.0 0 0 1.0 71.50 61.17 1.17
S-1.5 0 0 1.5 68.08 64.25 1.06
H-0 80 80 0.0 57.59 54.71 1.05
H-0.5 80 80 0.5 58.90 56.74 1.04
H-1.0 80 80 1.0 69.01 59.16 1.17
H-1.5 80 80 1.5 73.52 61.22 1.20
(a)
Rapture of steel fiber
(b)
Pull-out fiber
(c) (d)
Figure 7: Fracture surfaces of the prisms with different fiber contents: (a) B0.0, (b) B0.5, (c) B1.0, and (d) B1.5.
Advances in Civil Engineering 7
8. compared to that without fiber. The recorded deflections at
steel yielding were 4.17, 3.51, 3.62, and 2.98 mm for the solid
beams S-0, S-0.5, S-1.0, and S-1.5, respectively. This means
that the elastic stiffness of the beams increases with the
increase in fiber content.
Figure 11(b) clearly clarifies the superior flexural be-
havior of steel fiber reinforced hollow beams over the ones
without steel fiber. It is obvious in the figure that the in-
clusion of only 0.5% of steel fiber did not lead to significant
improvement. However, the inclusion of 1.0 and 1.5% steel
fiber is shown to have great impact on the overall structural
behavior of hollow beams. The yielding load of the hollow
beams H-0, H-0.5, H-1.0, and H-1.5 that contains 0, 0.5, 1.0,
and 1.5% steel fiber were 50.3, 46.6, 56.9, and 63.4, re-
spectively. Their corresponding yielding deflections were
3.72, 3.41, 3.39, and 3.36 mm, respectively. This means that
the elastic stiffness was almost equal for H-0 and H-0.5,
whereas it was 24 and 40% higher for H-1.0 and H-1.5
compared to H-0. Another obvious result is that the higher
the fiber content, the higher the peak load the hollow beams
could withstand. Similarly, the final deflection (ultimate
deflection at failure) was obviously increasing with the
(a) (b)
(c) (d)
(e) (f)
(g) (h)
Figure 10: Final cracking patterns of the tested beams after failure: (a) S-0, (b) H-0, (c) S-0.5, (d) H-0.5, (e) S-1.0, (f) H-1.0, (g) S-1.5, and (h) H-1.5.
Figure 9: Tested hollow beam under four-point load.
8 Advances in Civil Engineering
9. increase in fiber content in hollow beams, as shown in
Figure 11(b). The peak loads of the beams with fiber contents
of 0, 0.5, 1.0, and 1.5% were recorded to be 57.6, 58.9, 69.0,
and 73.5 kN, respectively, whereas their ultimate deflections
were approximately15.8, 16.2, 17.9, and 19.8 mm, re-
spectively. From the discussed results and the comparison
between Figures 11(a) and 11(b), it can be concluded that the
inclusion of steel fiber was more effective on hollow beams
than on solid beams.
Figure 12 compares the load-deflection curves of solid
and hollow beams having the same volumetric content of
steel fiber. Figure 12(a) shows that the solid beam without
fiber could retain higher yield and ultimate load capacities
than the corresponding hollow beam. It was recorded that
the cracking load of the hollow beam was approximately 5%
lower than that of the corresponding solid beam, whereas it
was 9% and 15% lower at yielding and ultimate load stages,
respectively. It should be reminded that both beams
exhibited some flexural-shear cracks outside the pure flex-
ural zone and failed in flexural-shear cracking.
Figure 12(b) shows explicitly that the flexural behavior of
S-0.5 was superior to that of the corresponding hollow beam
H-0.5. Comparing the load capacities of the two beams at
cracking, yielding, and peak stages, it was recorded that the
load carrying capacity of H-0.5 was 14.5% to 19.5% lower
than that of S-0.5. On the other hand, the flexural behavior of
the hollow beam with 1.0% fiber content (H-1.0) is quite
close to that of the solid beam S-1.0, as shown in
Figure 12(c). It is also shown in the figure that the yielding
load capacity of H-1.0 is 6.2% lower than that of the beam
S-1.0, whereas its peak load was lower by only 3.5% than that
of the beam S-1.0.
Figure 12(d) shows that although that the yielding load
capacity is slightly higher for the solid beam with 1.5% of steel
fiber (S-1.5), the peak load and its corresponding deflection
are noticeably higher for the hollow beam H-1.5 than the solid
beam S-1.5, which reflects that the differences in flexural
behavior between the solid beam and hollow beam are sig-
nificantly reduced and diminishes when higher steel fiber
contents are used. Comparing the displacement behaviors of
the solid and hollow beams in the four figures, it can also be
noticed that the length of the strain hardening and softening
regions are almost identical for solid and hollow beams,
except for the 1.5% fiber content beams, where the hollow
beam exhibited noticeably longer strain hardening region.
5.3. Deflection Ductility. The ductility of a reinforced beam
under flexural loading can be defined as the capacity of that
beam to maintain higher plastic deformations and consid-
erable loads beyond steel yielding until failure without
showing sudden brittle fracture [17]. The higher the ductility
index, the more ductile is the beam. Previous researchers
tried several ductility indices to express the most reasonable
representation for ductility. Some researchers used the peak
deflection, which is associated to the highest load resisted by
the beam, while others used the ultimate deflection, which
correspond to the failure load.
Several procedures were proposed by Park [45] to
evaluate the ultimate point (Δu) from the load-deflection
curve of a tested beam. One of these methods is the 20% load
reduction after reaching the peak load. Thus, the deflection
corresponding to 80% of the peak load on the plastic zone
beyond the peak load is considered as the ultimate de-
flection. Other previous researchers [12, 17] used the 20%
load-reduction method to evaluate the ductility of high
strength reinforced concrete beams. In the current experi-
mental work, it was noticed that the ultimate failure occurs
by concrete crushing very close to the 80% of the peak load
or beyond which the load-deflection curve becomes un-
stable. Therefore, the 20% load-reduction method was also
used in this study to obtain the ultimate deflection.
In this study, to evaluate the more reliable ductility
index, two ductility indices were calculated based on the
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
S-0
S-0.5
S-1.0
S-1.5
Py
Pp
Pu
(a)
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
H-0
H-0.5
H-1.0
H-1.5
Py
Pp
Pu
(b)
Figure 11: Effect of steel fiber content on load-deflection curves for (a) solid beams and (b) hollow beams.
Advances in Civil Engineering 9
10. recorded deflections at the yielding of steel (Δy), at the peak
load (Δp), and at the ultimate load (Δu). The first ductility
index is the peak ductility index (µp) calculated at the peak
stage and equals Δp/Δy, whereas the second is the ultimate
ductility index (µu), which is calculated at the ultimate stage
(Δu/Δy). The values of the three deflections and the two
ductility indices are listed in Table 4. Comparing the two
calculated ductility indices, it is shown that there is no
noticeable trend of ductility with fiber content when µp is
considered, whereas the results of the ultimate ductility
index (µp) are systematic with clear trend and agree with the
results obtained in the literature [12, 17]. Therefore, in the
following discussion, only µu is used and is termed simply as
ductility index. It was reported in the literature that ductility
index of not less than 3 is required for structures constructed
in high-seismic zones [17]. It can be seen in Table 3 that all
the tested beams exhibited ductility index higher than 3.7,
which reflects a high potential to absorb plastic energies
when subjected to high loading regimes.
The ductility index values of the four solid beams show
that the higher the fiber content, the higher the ductility
index. Similarly, comparison among the four hollow beams
show that ductility increases as fiber content increases.
Figure 13 shows the percentage increase in ductility index of
fibrous solid beams and hollow beams compared to the
nonfibrous solid beam (S-0). The figure shows that, for solid
beams, percentage increases of approximately 4 and 9% were
achieved when 0.5 and 1.0% fiber contents, respectively,
were incorporated, whereas the percentage increase jumped
to approximately 48% when 1.5% steel fiber was used. On the
other hand, it is clear that the percentage increases of 27, 41,
and 57% were recorded for the hollow beams that contain
0.5, 1.0, and 1.5% steel fiber, respectively. This means that the
inclusion of steel fiber enhanced the ductility of reinforced
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
S-0
H-0
Py
Pp
Pu
(a)
S-0.5
H-0.5
Py
Pp
Pu
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
(b)
Pp
Pu
S-1.0
H-1.0
Py
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
(c)
S-1.5
H-1.5
Py
Pp
Pu
0
20
40
60
80
0 5 10 15 20
Load
(kN)
Deflection (mm)
(d)
Figure 12: Comparison between load-deflection curves of solid and hollow beams for different fiber contents.
10 Advances in Civil Engineering
11. concrete beams, and that the maximum percentage increase
was achieved when 1.5% steel fiber was used. In the presence
of fibers, the firstly initiated cracks are restricted by the
bridging action of fibers across that crack, which reduces the
crack width and leads to the formation of more hair cracks.
Thus, the crack propagation is restricted, which increases the
load capacity within the postcracking region. Therefore, the
ability of the beam to absorb plastic deformations is in-
creased. Sun et al. [20] reported that the ductility was in-
creased as steel fiber content increased up to 1.5%, beyond
which no ductility gain was recorded. It is known that there
should be some optimum content of fibers, beyond which,
no further enhancement in strength or performance is
obtained. The optimum content depends mainly on the fiber
physical characteristics [13]. In this research, and within the
limit of the studied variables, the 1.5% volumetric content
was found to better enhance the load carrying capacity,
stiffness, and deflection.
It is obvious in Figure 13 that hollow beams exhibited
higher ductility compared to the solid beam S-0, as discussed
before or as compared to the corresponding solid beams
having the same fiber content. The percentage shown above
each twin of the bar charts in Figure 13 refers to the per-
centage gain of ductility index of each hollow beam over its
corresponding solid beam. It is shown that considerable
ductility gains of 6 to 29% were obtained for the hollow
beams compared with solid beams. This is a very encour-
aging result as the side length of the hole was more than half
the side length of the beam’s cross section. Thus, although
the beam cross-sectional area and hence its weight was
reduced by 28%, higher ductility was retained.
6. Conclusions
From the experimental work of this study on hollow and
solid steel fiber-reinforced high-strength concrete beams,
following are the most important conclusions:
(1) All solid and hollow fibrous beams failed in flexure
and exhibited flexural cracks along the pure bending
span, whereas those without steel fiber showed some
cracks within the shear spans in addition to the
flexural cracks and exhibited flexural-shear failure.
(2) In general, the flexural behavior of fibrous beams was
superior to that of beams without fiber because of the
crack bridging action of fibers. The cracking,
yielding, and peak load capacities increased due to
the incorporation of steel fibers both for solid and
hollow beams. The better enhancement in load
carrying capacity was mostly recorded for the 1.5%
fiber content. For both solid and hollow beams, the
gain of the beams with 1.5% fiber over those without
fiber in cracking, yielding, and peak loads were in the
ranges of approximately 24 to 49%, 17 to 26%, and
less than 1.0 to 28%, respectively. Moreover, it was
recorded that the higher the fiber content, the higher
is the stiffness of the beam.
(3) The hollow beams with fiber contents of 0, 0.5, and 1.0%
were observed to withstand lower loads at cracking,
yielding, and peak stages than their corresponding solid
beams, whereas this was not the case for the 1.5% fiber
hollow beam which exhibited higher peak load carrying
capacity than its corresponding solid beam.
(4) In general, all tested beams exhibited ductility in-
dices higher than 3.7. However, hollow beams
exhibited better ductility than solid beams, showing
higher ductility index values. The ductility index for
each type of beam increased as the fiber content
increased. The ductility index values of solid beams
ranged from 3.7 to 5.5, whereas those of hollow
beams were in the range of 4.2 to 5.9.
Data Availability
The data used to support the findings of this study are
available from the corresponding author upon request.
Conflicts of Interest
The authors declare that they have no conflicts of interest.
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