The blast resistance of structures used in buildings needs to be investigated due to the increased threat of a terrorist attack. The damage done by Composition B or Powergel to steel fibre reinforced reactive powder c...The blast resistance of structures used in buildings needs to be investigated due to the increased threat of a terrorist attack. The damage done by Composition B or Powergel to steel fibre reinforced reactive powder concrete （SFRPC） panels and ordinary reinforced concrete （RC） panels of equivalent static flexural strength is compared. A 0. 5 kg charge was detonated at a distance of 0. 1 m from the 1. 3 m × 1. 0 m × 0. 1 m （thick） panels, which were simply supported and spaning 1.3 m. Dynamic displacement measurements, high-speed video recording and visual examination of the panels for spall and breach were undertaken. The SFRPC panels withstood the bare charge blast better than the reinforced ordinary concrete panels. Neither type of panel was breached using a O. 5 kg charge, The RC panel exhibited more spalling when Composition B was used. Under successive Composition B loading conditions, the RC panel was breached. In comparison the SFRPC panel was not breached. Exposure to fragmenting charge loading conditions confirmed these performance differences between the SFRPC panel and the reinforced ordinary concrete panel.展开更多
Based on an engineering background of a deep tunneling in weak rocks, the numerical modeling is used to compare different support schemes of tunnel at great depth in this paper. Focused on the general behaviors of wea...Based on an engineering background of a deep tunneling in weak rocks, the numerical modeling is used to compare different support schemes of tunnel at great depth in this paper. Focused on the general behaviors of weak rocks at great depth, a tunneling scheme with rock bolting and steel fibre reinforced sprayed concrete is proposed. This scheme is practiced successfully at a deep tunnel in weak rocks in Coal Mine No 10 of Hebi Coal Mining Administration.展开更多
This paper reports investigation conducted to study the fatigue performance of steel fibre reinforced concrete (SFRC) containing fibres of mixed aspect ratio. An extensive experimental program was conducted in which 9...This paper reports investigation conducted to study the fatigue performance of steel fibre reinforced concrete (SFRC) containing fibres of mixed aspect ratio. An extensive experimental program was conducted in which 90 flexural fatigue tests were carried out at different stress levels on size 500 mm×100 mm×100 mm SFRC specimens respectively containing 1.0%, 1.5% and 2.0% volume fraction of fibres. About 36 static flexural tests were also conducted to determine the static flexural strength prior to fatigue testing. Each volume fraction of fibres incorporated corrugated mixed steel fibres of size 0.6 mm×2.0 mm×25 mm and 0.6 mm×2.0 mm×50 mm in ratio 50:50 by weight. The results are presented both as S-N relationships, with the maximum fatigue stress expressed as a percentage of the strength under static loading, and as relationships between actually applied fatigue stress and number of loading cycles to failure. Two-million-cycle fatigue strengths of SFRC containing different volume fractions of mixed fibres were obtained and compared with plain concrete.展开更多
The results of an analytical investigation of the flexural behaviour of Steel Fibre Reinforced Concrete （SFRC） beams are presented. The complete response of the SFRC beams under displacement controlled static loadin...The results of an analytical investigation of the flexural behaviour of Steel Fibre Reinforced Concrete （SFRC） beams are presented. The complete response of the SFRC beams under displacement controlled static loading was obtained using nonlinear Finite Element （FE） techniques implemented with the help of ATENA 2D soRware. Issues relating to the behaviour of SFRC which have a direct bearing on the FE modelling are discussed with relevance to the software employed for the nonlinear analysis. Constitutive models amenable to numerical analysis for steel fibrous concrete are presented. The structural response throughout the loading regime was captured in terms of the load-deflection behaviour, which in addition to the post-peak response characterized the failure mode of the test beams. The crack patterns at crack initiation and at the end of the tests were also recorded. Experimental results from the specimens of two other investigators were used as control values for this investigation. The response of the specimens of this investigation was evaluated in terms of initial tangent stiffness, peak loads and toughness. Good match was obtained between the results from this investigation and corresponding experimentally obtained values, wherever available. The influence of the fibre content is reflected in the observed trends in peak loads, deflection at peak loads and toughness, which are in broad agreement with known behavioral patterns of SFRC.展开更多
This paper presents a precise solution to predict the behavior of steel fiber reinforced concrete(SFRC) under the four point bending test(FPBT).All the force components at the beam section(before and after cracking) a...This paper presents a precise solution to predict the behavior of steel fiber reinforced concrete(SFRC) under the four point bending test(FPBT).All the force components at the beam section(before and after cracking) are formulated by applying these assumptions:a realistic stress-strain model is used for concrete behavior in compression,a linear response is considered for the uncracked tension region in a concrete constitutive model,and an exponential relationship is proposed as a stress-crack opening in the crack region which requires two parameters.Then the moment capacity of the critical cracked section is calculated by using these forces and satisfying equilibrium law at the section.Parametric studies are done on the behavior of SFRC to assess the sensitivity of the solution.Finally,this solution is validated with some existing experimental data.The result shows the proposed solution is able to estimate the behavior of SFRC under FPBT.展开更多
Recently, the use of steel fiber at high rates has been introduced as the sole method of reinforcement for fully elevated-suspended slabs having long span such as 5 m to 8 m each way, with a span to depth ratio of up ...Recently, the use of steel fiber at high rates has been introduced as the sole method of reinforcement for fully elevated-suspended slabs having long span such as 5 m to 8 m each way, with a span to depth ratio of up to 33 [1]. As a result of long practical experience the total replacement of traditional rebar is a new routine. Now it is also used in the designing of SFRC pavements over conventional concrete pavements. Within the project framework a demonstration of a steel-fiber-reinforced roller-compacted concrete (SFR-RCC) pavement was constructed in a rural as well as urban area. In order to assess the economical condition of the demonstration pavement, life cycle assessment (LCA) and life cycle cost analysis (LCCA) studies were undertaken. This is the advancement study of the various papers which is already published in many publications which serve as the main and important source of study for the research. Many applications of steel fiber are listed in the paper but the main output of this paper is that SFR-RCC is more economically sustainable than others and also helps in reducing the thickness of the pavement up to 20 to 25 percent, due to the excessive strength of steel fiber. The roads of the present system required high cost investment. And the life period is almost 20 years theoretically but the actual life of the road is depending on the maintenance and the applied load. The constructions of road have been done since the 3500 BC but the method does not change fully. Also the cost of the construction is increased continuously;as a result, the construction of roads is more and more complicated and time taken. For the better and economical construction of the roads, we use steel fibers in the composite pavement. The theoretical plan of the construction of composite pavement is given in the methodology, which gives the appropriate idea about the construction of road using steel fiber. Here we use the composite pavement in which the steel fiber is mixed in the concrete layer, after which the bitumen layer is laid for the smooth and suitable riding of the vehicles.展开更多
文摘The blast resistance of structures used in buildings needs to be investigated due to the increased threat of a terrorist attack. The damage done by Composition B or Powergel to steel fibre reinforced reactive powder concrete （SFRPC） panels and ordinary reinforced concrete （RC） panels of equivalent static flexural strength is compared. A 0. 5 kg charge was detonated at a distance of 0. 1 m from the 1. 3 m × 1. 0 m × 0. 1 m （thick） panels, which were simply supported and spaning 1.3 m. Dynamic displacement measurements, high-speed video recording and visual examination of the panels for spall and breach were undertaken. The SFRPC panels withstood the bare charge blast better than the reinforced ordinary concrete panels. Neither type of panel was breached using a O. 5 kg charge, The RC panel exhibited more spalling when Composition B was used. Under successive Composition B loading conditions, the RC panel was breached. In comparison the SFRPC panel was not breached. Exposure to fragmenting charge loading conditions confirmed these performance differences between the SFRPC panel and the reinforced ordinary concrete panel.
文摘Based on an engineering background of a deep tunneling in weak rocks, the numerical modeling is used to compare different support schemes of tunnel at great depth in this paper. Focused on the general behaviors of weak rocks at great depth, a tunneling scheme with rock bolting and steel fibre reinforced sprayed concrete is proposed. This scheme is practiced successfully at a deep tunnel in weak rocks in Coal Mine No 10 of Hebi Coal Mining Administration.
基金Project supported by the Indian Council for Cultural Relations,India
文摘This paper reports investigation conducted to study the fatigue performance of steel fibre reinforced concrete (SFRC) containing fibres of mixed aspect ratio. An extensive experimental program was conducted in which 90 flexural fatigue tests were carried out at different stress levels on size 500 mm×100 mm×100 mm SFRC specimens respectively containing 1.0%, 1.5% and 2.0% volume fraction of fibres. About 36 static flexural tests were also conducted to determine the static flexural strength prior to fatigue testing. Each volume fraction of fibres incorporated corrugated mixed steel fibres of size 0.6 mm×2.0 mm×25 mm and 0.6 mm×2.0 mm×50 mm in ratio 50:50 by weight. The results are presented both as S-N relationships, with the maximum fatigue stress expressed as a percentage of the strength under static loading, and as relationships between actually applied fatigue stress and number of loading cycles to failure. Two-million-cycle fatigue strengths of SFRC containing different volume fractions of mixed fibres were obtained and compared with plain concrete.
文摘The results of an analytical investigation of the flexural behaviour of Steel Fibre Reinforced Concrete （SFRC） beams are presented. The complete response of the SFRC beams under displacement controlled static loading was obtained using nonlinear Finite Element （FE） techniques implemented with the help of ATENA 2D soRware. Issues relating to the behaviour of SFRC which have a direct bearing on the FE modelling are discussed with relevance to the software employed for the nonlinear analysis. Constitutive models amenable to numerical analysis for steel fibrous concrete are presented. The structural response throughout the loading regime was captured in terms of the load-deflection behaviour, which in addition to the post-peak response characterized the failure mode of the test beams. The crack patterns at crack initiation and at the end of the tests were also recorded. Experimental results from the specimens of two other investigators were used as control values for this investigation. The response of the specimens of this investigation was evaluated in terms of initial tangent stiffness, peak loads and toughness. Good match was obtained between the results from this investigation and corresponding experimentally obtained values, wherever available. The influence of the fibre content is reflected in the observed trends in peak loads, deflection at peak loads and toughness, which are in broad agreement with known behavioral patterns of SFRC.
文摘This paper presents a precise solution to predict the behavior of steel fiber reinforced concrete(SFRC) under the four point bending test(FPBT).All the force components at the beam section(before and after cracking) are formulated by applying these assumptions:a realistic stress-strain model is used for concrete behavior in compression,a linear response is considered for the uncracked tension region in a concrete constitutive model,and an exponential relationship is proposed as a stress-crack opening in the crack region which requires two parameters.Then the moment capacity of the critical cracked section is calculated by using these forces and satisfying equilibrium law at the section.Parametric studies are done on the behavior of SFRC to assess the sensitivity of the solution.Finally,this solution is validated with some existing experimental data.The result shows the proposed solution is able to estimate the behavior of SFRC under FPBT.
文摘Recently, the use of steel fiber at high rates has been introduced as the sole method of reinforcement for fully elevated-suspended slabs having long span such as 5 m to 8 m each way, with a span to depth ratio of up to 33 [1]. As a result of long practical experience the total replacement of traditional rebar is a new routine. Now it is also used in the designing of SFRC pavements over conventional concrete pavements. Within the project framework a demonstration of a steel-fiber-reinforced roller-compacted concrete (SFR-RCC) pavement was constructed in a rural as well as urban area. In order to assess the economical condition of the demonstration pavement, life cycle assessment (LCA) and life cycle cost analysis (LCCA) studies were undertaken. This is the advancement study of the various papers which is already published in many publications which serve as the main and important source of study for the research. Many applications of steel fiber are listed in the paper but the main output of this paper is that SFR-RCC is more economically sustainable than others and also helps in reducing the thickness of the pavement up to 20 to 25 percent, due to the excessive strength of steel fiber. The roads of the present system required high cost investment. And the life period is almost 20 years theoretically but the actual life of the road is depending on the maintenance and the applied load. The constructions of road have been done since the 3500 BC but the method does not change fully. Also the cost of the construction is increased continuously;as a result, the construction of roads is more and more complicated and time taken. For the better and economical construction of the roads, we use steel fibers in the composite pavement. The theoretical plan of the construction of composite pavement is given in the methodology, which gives the appropriate idea about the construction of road using steel fiber. Here we use the composite pavement in which the steel fiber is mixed in the concrete layer, after which the bitumen layer is laid for the smooth and suitable riding of the vehicles.
