Steel, polyolefin and carbon fiber reinforced concretes were combined with traditional transverse steel reinforcement in the form of steel spirals. The complete stress-strain relationship and the ductility of the concrete in compression in both the unconfined and confined states was evaluated. The compressive toughness was evaluated both according to the Japanese Standard JSCE - SP% and according to a new method proposed in the present work. The experimental program consisted of testing concrete cylinders under compression at two different strength levels: normal (48 MPa) and high strength (70 MPa), reinforced with different volume percentages of steel, polyolefin and carbon fibers. These tests were then repeated with the addition of spiral reinforcement with different pitches (25 and 50 mm). It was found that by combining fibers and steel spirals it is possible: (1) to obtain a high level of fracture energy dissipation, which could previously be obtained only by using a high volume percentage of spiral steel; and (2) to improve the maximum strain of the concrete, corresponding to the first failure of the spiral steel.
{"title":"Compressive Toughness Characterization of Normal and High-Strength Fiber Concrete Reinforced With Steel Spirals","authors":"G. Campione, S. Mindess","doi":"10.14359/5526","DOIUrl":"https://doi.org/10.14359/5526","url":null,"abstract":"Steel, polyolefin and carbon fiber reinforced concretes were combined with traditional transverse steel reinforcement in the form of steel spirals. The complete stress-strain relationship and the ductility of the concrete in compression in both the unconfined and confined states was evaluated. The compressive toughness was evaluated both according to the Japanese Standard JSCE - SP% and according to a new method proposed in the present work. The experimental program consisted of testing concrete cylinders under compression at two different strength levels: normal (48 MPa) and high strength (70 MPa), reinforced with different volume percentages of steel, polyolefin and carbon fibers. These tests were then repeated with the addition of spiral reinforcement with different pitches (25 and 50 mm). It was found that by combining fibers and steel spirals it is possible: (1) to obtain a high level of fracture energy dissipation, which could previously be obtained only by using a high volume percentage of spiral steel; and (2) to improve the maximum strain of the concrete, corresponding to the first failure of the spiral steel.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124278710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An experimental investigation was conducted to assess the potential of steel fibers as secondary reinforcement in prestressed hollow core slabs. Following a brief laboratory study and a feasibility trial, a series of fibre reinforced extruded slabs were made at the premises of a local manufacturer and subsequently tested in shear: one of a number of potential modes of failure which cause concern in this type of slab because of the lack of shear or secondary reinforcement. The addition of the fibres increased both the ultimate strength and toughness of the slabs leading to safer and more controlled failures. The predictive equations of other researchers were shown to accurately estimate the shear strength in the case of plain hollow core slabs, but to overestimate the shear enhancement due to adding steel fibres. Additionally, the effect of the manufacturing process, in which the concrete is compacted by rotating augers, on the fibre distribution and orientation was investigated. While fibres were found to be randomly distributed within the cross-section, a tendency to align vertically within the webs was observed. This has particular relevance to the vertical shear performance.
{"title":"Steel Fiber Reinforcement for Extruded Prestressed Hollow Core Slabs","authors":"C. Peaston, K. Elliott, K. Paine","doi":"10.14359/5523","DOIUrl":"https://doi.org/10.14359/5523","url":null,"abstract":"An experimental investigation was conducted to assess the potential of steel fibers as secondary reinforcement in prestressed hollow core slabs. Following a brief laboratory study and a feasibility trial, a series of fibre reinforced extruded slabs were made at the premises of a local manufacturer and subsequently tested in shear: one of a number of potential modes of failure which cause concern in this type of slab because of the lack of shear or secondary reinforcement. The addition of the fibres increased both the ultimate strength and toughness of the slabs leading to safer and more controlled failures. The predictive equations of other researchers were shown to accurately estimate the shear strength in the case of plain hollow core slabs, but to overestimate the shear enhancement due to adding steel fibres. Additionally, the effect of the manufacturing process, in which the concrete is compacted by rotating augers, on the fibre distribution and orientation was investigated. While fibres were found to be randomly distributed within the cross-section, a tendency to align vertically within the webs was observed. This has particular relevance to the vertical shear performance.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117329478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Massicotte, B. Mossor, A. Filiatrault, S. Tremblay
It is known that Steel Fiber Reinforced Concrete (SFRC) has advantages over plain concrete. In particular, fiber reinforcement makes concrete tougher and more ductile. Although these attributes are appealing for earthquake resisting structures, design codes do not yet incorporate specifications relative to the use of SFRC for structural applications. Recent developments have indicated a good potential for SFRC in structural and seismic applications. In the first part of this paper, the beneficial effects of SFRC in the seismic design of columns are briefly reviewed. The paper then presents an overview of an ongoing research project on column strength and ductility in which 18 columns were tested in uniaxial compression. The variables considered were the fiber content of 0%, 0.5% and 1.0% per volume, the amount of transverse reinforcement for confining the column core, and the confinement provided by the fibers in the cover. It is shown that SFRC improves significantly the post-peak behavior of columns for all hoop spacings and that SFRC can be juxtaposed with reduced traditional confining reinforcement under the same seismic design philosophy. Although SFRC in the cover delay its spalling, no noticeable confining contribution of the cover was observed. Fibers do not really confine concrete, but rather change the failure mode by limiting the progression of cracks and enhancing the aggregate interlock along failure planes.
{"title":"Compressive Strength and Ductility of Steel Fiber Reinforced Concrete","authors":"B. Massicotte, B. Mossor, A. Filiatrault, S. Tremblay","doi":"10.14359/5527","DOIUrl":"https://doi.org/10.14359/5527","url":null,"abstract":"It is known that Steel Fiber Reinforced Concrete (SFRC) has advantages over plain concrete. In particular, fiber reinforcement makes concrete tougher and more ductile. Although these attributes are appealing for earthquake resisting structures, design codes do not yet incorporate specifications relative to the use of SFRC for structural applications. Recent developments have indicated a good potential for SFRC in structural and seismic applications. In the first part of this paper, the beneficial effects of SFRC in the seismic design of columns are briefly reviewed. The paper then presents an overview of an ongoing research project on column strength and ductility in which 18 columns were tested in uniaxial compression. The variables considered were the fiber content of 0%, 0.5% and 1.0% per volume, the amount of transverse reinforcement for confining the column core, and the confinement provided by the fibers in the cover. It is shown that SFRC improves significantly the post-peak behavior of columns for all hoop spacings and that SFRC can be juxtaposed with reduced traditional confining reinforcement under the same seismic design philosophy. Although SFRC in the cover delay its spalling, no noticeable confining contribution of the cover was observed. Fibers do not really confine concrete, but rather change the failure mode by limiting the progression of cracks and enhancing the aggregate interlock along failure planes.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116171833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of steel fibers as shear reinforcement in reinforced concrete beams is very promising. In this paper, an optimized high strength concrete with steel fibers is used in rectangular beams, reinforced with longitudinal bars. This solution is compared with classical reinforced concrete. Five specimens are tested in four-point bending. The 28-day mean compressive strength of concrete is 90 MPa measured on cylinders. The global behavior of the beams is the same for both solutions. The load at the onset of cracking is equal for all tested beams but the crack opening is smaller with steel fibers. No problems were encountered concerning ductility.
{"title":"High-Strength Concrete Beams Submitted to Shear: Steel Fibers Versus Stirrups","authors":"P. Cananova, P. Rossi","doi":"10.14359/5521","DOIUrl":"https://doi.org/10.14359/5521","url":null,"abstract":"The use of steel fibers as shear reinforcement in reinforced concrete beams is very promising. In this paper, an optimized high strength concrete with steel fibers is used in rectangular beams, reinforced with longitudinal bars. This solution is compared with classical reinforced concrete. Five specimens are tested in four-point bending. The 28-day mean compressive strength of concrete is 90 MPa measured on cylinders. The global behavior of the beams is the same for both solutions. The load at the onset of cracking is equal for all tested beams but the crack opening is smaller with steel fibers. No problems were encountered concerning ductility.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"217 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132447944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mechanical behavior of a few plain and fiber-reinforced high-performance concretes is studied here by means of direct tensile tests and three-point bending tests, and a special "identification" procedure is adopted in order to cleanse the stress-strain and stress-displacement curves of any undesired structural effect. Then the overall behavior of two P/C beams typifying the sub-elements of a hollow-core slab is examined, with and without fibers to study crack formation and propagation (by optical interferometry) and structural ductility.
{"title":"Fiber Reinforced High-Performance Concrete Beams Material and Structural Behavior","authors":"M. Marazzini, G. Rosati","doi":"10.14359/5520","DOIUrl":"https://doi.org/10.14359/5520","url":null,"abstract":"The mechanical behavior of a few plain and fiber-reinforced high-performance concretes is studied here by means of direct tensile tests and three-point bending tests, and a special \"identification\" procedure is adopted in order to cleanse the stress-strain and stress-displacement curves of any undesired structural effect. Then the overall behavior of two P/C beams typifying the sub-elements of a hollow-core slab is examined, with and without fibers to study crack formation and propagation (by optical interferometry) and structural ductility.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128414202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Processed cellulose fibers provide high levels of elastic modulus, tensile strength, bond strength to concrete, and durability. Their fine diameter also yields a close fiber spacing at relatively low fiber volume fractions, and allows them to establish a strong presence in the interface zones between reinforcing bars and concrete. Specialty cellulose fibers have been recently developed for convenient dispersion into normal concrete mixtures using conventional mixing procedures. This research project investigated the effect to specialty cellulose fibers at volume fractions of about 0.1% on the strength and toughness of bond between deformed bars and concrete. The experimental results were indicative of the effectiveness of specialty cellulose fibers in enhancing bond strength and toughness. The positive impact of specialty cellulose fibers on bond strength was more pronounced as a fiber volume fractions increased to the upper limit of 0.18% considered in this investigation.
{"title":"Bond of Deformed Bars to Concrete: Effects of Specialty Cellulose Fibers","authors":"P. Soroushian, S. Ravanbakhsh","doi":"10.14359/5525","DOIUrl":"https://doi.org/10.14359/5525","url":null,"abstract":"Processed cellulose fibers provide high levels of elastic modulus, tensile strength, bond strength to concrete, and durability. Their fine diameter also yields a close fiber spacing at relatively low fiber volume fractions, and allows them to establish a strong presence in the interface zones between reinforcing bars and concrete. Specialty cellulose fibers have been recently developed for convenient dispersion into normal concrete mixtures using conventional mixing procedures. This research project investigated the effect to specialty cellulose fibers at volume fractions of about 0.1% on the strength and toughness of bond between deformed bars and concrete. The experimental results were indicative of the effectiveness of specialty cellulose fibers in enhancing bond strength and toughness. The positive impact of specialty cellulose fibers on bond strength was more pronounced as a fiber volume fractions increased to the upper limit of 0.18% considered in this investigation.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128531031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"\"Effect of Various Types of Fibers on Bond Capacity Experimental, Analytical, and Numerical Investigations\"","authors":"K. Noghabai","doi":"10.14359/5524","DOIUrl":"https://doi.org/10.14359/5524","url":null,"abstract":"","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129676690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CRC (Compact Reinforced Composite) is the designation for a special type of fiber reinforced concrete with high strength ( 150-400 MPa) and closely spaced reinforcing bars. The dense matrix with water/powder ratios of typically 0.16 provide a good bond to fibers and reinforcing bars, and the large ·content of steel fibers provide the ductility necessary for utilizing reinforcement effectively. The steel fiber content is typically 2-6% by volume and the content of reinforcing steel is 2-10% by volume. The improved durability of the matrix due to a high micro silica content makes it possible to use a concrete cover to the reinforcement of only 10 mm in aggressive environments, improving the effectiveness of the reinforcement.
{"title":"High-Srength Fiber Reinforced Concrete Utilizing Closely Spaced Reinforcing Bars","authors":"B. Aarup","doi":"10.14359/5518","DOIUrl":"https://doi.org/10.14359/5518","url":null,"abstract":"CRC (Compact Reinforced Composite) is the designation for a special type of fiber reinforced concrete with high strength ( 150-400 MPa) and closely spaced reinforcing bars. The dense matrix with water/powder ratios of typically 0.16 provide a good bond to fibers and reinforcing bars, and the large ·content of steel fibers provide the ductility necessary for utilizing reinforcement effectively. The steel fiber content is typically 2-6% by volume and the content of reinforcing steel is 2-10% by volume. The improved durability of the matrix due to a high micro silica content makes it possible to use a concrete cover to the reinforcement of only 10 mm in aggressive environments, improving the effectiveness of the reinforcement.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121612780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Considerable progress has recently been achieved in strength and ductility of concretes. The use of superplasticizers and large amounts of silica fume led to densified cementitious matrices and improved adherence to the fiber reinforcement. These two properties are obtained with Compact Reinforced Composite (CRC) developed at Aalborg Portland and closely studied during a 3-year EC. The investigations reported in this paper cover the application of ultra high strength-fiber reinforced concrete to enhance performance of beams, columns and beam to column connections. Mechanical tests were performed on full-scale structural elements. Beams of 13 m in length, columns of 2.9 m in compression with and without eccentricity of the load, and beam to column connections were tested. In all cases, concrete strengths of more than 150 MPa were achieved. Due to CRC's high compacity and its extreme resistance to the penetration of aggressive elements, the CRC cover to the reinforcement was typically reduced from 30 mm to at least 12 mm. It has been shown that a reduction in concrete cover to the reinforcement is compatible with the requirements of structural applications. The tests carried out have shown the possibility of using ultra-high strength concrete for large-scale structural concrete elements and opens new fields of applications. This contributes to saving raw materials, weight and volume and to improving ductility and durability.
{"title":"Structural Applications Using Ultra High-Strength Fiber Reinforced Concrete","authors":"G. Bernier, M. Behloul, N. Roux","doi":"10.14359/5522","DOIUrl":"https://doi.org/10.14359/5522","url":null,"abstract":"Considerable progress has recently been achieved in strength and ductility of concretes. The use of superplasticizers and large amounts of silica fume led to densified cementitious matrices and improved adherence to the fiber reinforcement. These two properties are obtained with Compact Reinforced Composite (CRC) developed at Aalborg Portland and closely studied during a 3-year EC. The investigations reported in this paper cover the application of ultra high strength-fiber reinforced concrete to enhance performance of beams, columns and beam to column connections. Mechanical tests were performed on full-scale structural elements. Beams of 13 m in length, columns of 2.9 m in compression with and without eccentricity of the load, and beam to column connections were tested. In all cases, concrete strengths of more than 150 MPa were achieved. Due to CRC's high compacity and its extreme resistance to the penetration of aggressive elements, the CRC cover to the reinforcement was typically reduced from 30 mm to at least 12 mm. It has been shown that a reduction in concrete cover to the reinforcement is compatible with the requirements of structural applications. The tests carried out have shown the possibility of using ultra-high strength concrete for large-scale structural concrete elements and opens new fields of applications. This contributes to saving raw materials, weight and volume and to improving ductility and durability.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121676801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structural behavior of steel fiber reinforced concrete beams in shear is studied. A comprehensive experimental program has been set up and several series of reinforced concrete beams with steel fibers have been tested. The test variables include the volume contents of steel fibers and stirrups. The fiber contents varies from 0% to 2% by volume. It is seen from these tests that the cracking and ultimate shear strengths increase as fiber contents increase. The present study indicates that fiber reinforcement can reduce the amount of shear stirrups to obtain same strength. The combination of fibers and stirrups may accomplish strength requirements as well as ductility requirements. A theoretical approach is proposed to predict the shear strength of reinforced concrete beams containing steel fibers and good correlation is obtained with test data. The present study allows more efficient structural application of steel fibers for shear reinforcement in reinforced concrete structures.
{"title":"Structural Behavior of Steel Fiber Reinforced Concrete Beams in Shear","authors":"B. Oh, D. Lim, K. Hong, S. Yoo, S. Chae","doi":"10.14359/5519","DOIUrl":"https://doi.org/10.14359/5519","url":null,"abstract":"The structural behavior of steel fiber reinforced concrete beams in shear is studied. A comprehensive experimental program has been set up and several series of reinforced concrete beams with steel fibers have been tested. The test variables include the volume contents of steel fibers and stirrups. The fiber contents varies from 0% to 2% by volume. It is seen from these tests that the cracking and ultimate shear strengths increase as fiber contents increase. The present study indicates that fiber reinforcement can reduce the amount of shear stirrups to obtain same strength. The combination of fibers and stirrups may accomplish strength requirements as well as ductility requirements. A theoretical approach is proposed to predict the shear strength of reinforced concrete beams containing steel fibers and good correlation is obtained with test data. The present study allows more efficient structural application of steel fibers for shear reinforcement in reinforced concrete structures.","PeriodicalId":117541,"journal":{"name":"SP-182: Structural Applications of Fiber Reinforced Concrete","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130834491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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