SFRC used RC Beam and its Increasing Torsional Strength

Polymers, 2022

Fibres have long been utilized in the construction sector to improve the mechanical qualities of structural elements such as beams, columns, and slabs. This study aims to review the torsional behaviour of various forms of fibre reinforced concrete to identify possible enhancements and the practicability of concrete structural beams. Concrete reinforced steel fibre, synthetic fibre, and hybrid fibre are examples of fibre reinforced concrete. The review found that the mixing, orientation, and volume of fibres, the size of coarse particles, the aspect ratio of fibres, and the stiffness of fibres all affect the torsional strength of fibre reinforced concrete. Nevertheless, the application of fibres to recycled self-consolidating concrete of various forms needs to be explored and studied to ascertain its feasibility to facilitate greener concrete. Thus, with the results compiled in this review paper, it was possible to delimit advances and gaps on the effect of editing reinforcement fibr...

for decades for their improved flexural strength, direct tensile strength, fatigue strength, shear and torsional strength, shock resistance, ductility and failure toughness. In Bangladesh, it is not yet well introduced in the construction industry due to lack of reliable experimental results and Finite Element (FE) modeling. To this end, this research intends to provide evaluation of extensive analyses on the flexural and shear capacity enhancements of the RC specimens in ANSYS 10.0 FE platform. Poisson's ratio, tensile strength, modulus of elasticity, compressive stress-strain behaviour, shear transfer coefficients for open or close cracks of plain concrete and SFRC are taken as governing parameters to validate the FE models. The strategy to observe the improvement of flexural capacity RC members made of plain concrete and SFRC is to create the models weak in flexure by providing no flexural reinforcement but higher web reinforcements. In case of evaluating shear capacity, this scenario is made opposite. In this way the actual capacity enhancements are figured out. This study provides reliable FE models of RC members made of SFRC on the basis of experimental outputs which may help the construction industry of Bangladesh to introduce this composite material.

ACI Structural Journal, 2016

Buildings

Over the past few decades, numerous studies have explored the use of steel fiber (SF) as an alternative to transverse reinforcement rebars in reinforced concrete beams, either partially or completely replacing them. However, there are limited studies that have investigated the effect of fiber dosage and length on reinforced concrete beam performance under torsional loads without the use of transverse reinforcement rebars. In this study, experimental investigations were conducted to examine the performance of reinforced SF concrete beams subjected to torsional load, utilizing SFs as a complete substitution of transverse reinforcement rebars. Ten different concrete mixes with varying dosages of SFs, namely 0%, 0.5%, 1.0%, and 1.5%, were examined while maintaining the same aspect ratio for fiber length and diameter. The results revealed that the addition of SFs in the concrete mix had an impact on its properties, reducing workability but increasing flexural, tensile, and compressive st...

Buildings

Fiber-reinforced concrete is widely acknowledged for its ability to resist cracking effectively and limit its propagation. By preventing cracks from spreading, the addition of fiber composites to concrete can enhance its extensibility and tensile strength, not only at the initial point of cracking but also at its maximum capacity. Additionally, the fibers in fiber-reinforced concrete are capable of binding the matrix, even when exposed to significant cracking. However, there is limited information available about the behavior of fiber-reinforced concrete under a bending moment combined with torsion. This study aims to investigate the structural behavior of fiber-reinforced concrete members subjected to a bending moment with a torsion to moment ratio equal to 1. Synthetic and steel fibers of 1.0% content with different lengths (19, 35, and 55 mm for synthetic fiber and 13 mm for straight and hook steel fibers) were mixed with concrete mixtures to examine the effects of fiber lengths ...

Extensively used material in construction industry is concrete this is because of good workability and ability to be moulded to any shape. Ordinary cement concrete possesses very low tensile strength, limited ductility and less resistance to cracking. The concrete shows the brittle behaviour and fails to handle tensile loading hence leads to internal micro cracks which are mainly responsible for brittle failure of concrete. In this era, RCC constructions have their own structural and durability requirements, every structure has its own intended purpose and hence to meet this purpose, modification in traditional cement concrete has become mandatory. It has been proved that different type of fibers added in specific percentage to concrete improves the mechanical properties, durability and serviceability of the structure. As compared to other fibers it is now established that one of the important properties of Steel Fiber Reinforced Concrete (SFRC) is its superior resistance to crackin...

Cement concrete is the most extensively used construction material in the world. The reason for its extensive use is that it provides good workability and can be moulded to any shape. Ordinary cement concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Internal micro cracks, leading to brittle failure of concrete. In this modern age, civil engineering constructions have their own structural and durability requirements, every structure has its own intended purpose and hence to meet this purpose, modification in traditional cement concrete has become mandatory. It has been found that different type of fibers added in specific percentage to concrete improves the mechanical properties, durability and serviceability of the structure. It is now established that one of the important properties of Steel Fiber Reinforced Concrete (SFRC) is its superior resistance to cracking and crack propagation. In this paper Flexure behaviour of concrete wit...

Steel fiber reinforced concrete (SFRC) is used for its improved shear resistance, ductility and crack control properties. Steel fibers distributed randomly to a concrete mix act as crack arrestors, changing concrete from a brittle material to a ductile one, in addition to improving toughness and rigidity. To evaluate the shear capacity enhancement of SFRC, reinforced concrete (RC) beams are cast and tested in a 1000 kN capacity digital universal testing (UTM) machine under two point loading. The specimens are shear critical (SC) beams with only longitudinal reinforcement to observe the actual shear capacity enhancements due to steel fibers. In this work, the laboratory prepared end enlarged type of steel fibers of three aspect ratio are used, i.e. 40, 60 and 80 to make the SFRC and control beam (without steel fiber) for comparing the results. The shear capacity is found to be enhanced 25%, 29% and 18% for SFRC made of steel fiber aspect ratio (SFAR) 40, 60 and 80, respectively. Thes...

Concrete is a brittle material and is very weak in tension. When steel fibers are added to a concrete mix, fibers distribute randomly and act as crack arrestors, changing concrete from a brittle material to a ductile one and prevent brittle failure. Experimental investigations are conducted to increase the tensile strength of concrete by using steel fiber. Volume fraction of steel fiber used in this study is 1.5%. In this study low aspect ratio of fiber is used and sufficient capacity enhancement is attained. Two different aggregate types are used to make concrete i.e. stone and brick aggregate and the effects of SFRC on these two types of concretes are evaluated. Stone and brick concretes show substantial increase the flexural tension, splitting tension and direct tension (by dogbone specimen) capacity as well as ductility due to the presence of steel fibers. Total 8 compression cylinders, 8 split cylinders, 8 dogbone specimens (direct tension) and 8 beams (flexural tension) are ca...

Engineering Structures, 2020

Past research has used synthetic fiber (SY.F) and steel fiber (ST.F) for decades to advance concrete mechanical characteristics, including shear, tensile, and flexural strengths. Nevertheless, there is limited information concerning the torsional concrete reinforced with SY.F and ST.F performance. This research aims to explore the torsional performance of hollow reinforcement concrete beams reinforced with various fiber types. The fiber content of 1% with three different lengths of SY.F, 19, 38, and 57 mm, along with 13 mm of ST.F, was used. Two specimens were cast with normal concrete without using fibers as control beams and four hollow beams with ST.F and SY.F. To use a pure torsional load on the tested samples, an innovative test method was employed. The twisting angle of tested beams was calculated at each interval of the load as well as the first crack load and failure load. Outcomes illustrated that the utilizing of SY.F and ST.F in the reinforced concrete beams (RCB) enhanced the overall performance under torsional load compared to the control beam behaviors. This enhancement in the performance was relative to the fiber type and length. For the first cracking load, the tested beams reinforced with the ST.F and SY.F of 19 and 37 mm lengths showed approximately the same value. Also, the beam reinforced with the SY.F length of 55 mm exhibited the highest first cracking load value, among other tested beams. As the fiber length increases of SY.F, the ultimate load capacity was raised by 4.7, 9.4, and 21.9% for beams cast with 19, 37, and 55 mm fiber length, respectively. For the ST.F reinforcement concrete beam, the ultimate load capacity was raised by 5.5%. Therefore, due to the significant impact of SY.F on the torsional performance, it is recommended using SY.F with normal concrete. related to the amount of fiber, length, geometry, and mechanical characteristics. Research to date on using ST.F for reinforcing concrete beams has reported an enhancement in the structural performance. Nevertheless, there is no designing equation for reinforcement concrete beams that reinforced by SY.F under the torque load. Also, ACI, Eurocode, and BS (British Specifications) specifications do not have any details related to the hollow beam design with SY.F reinforced concrete under torsional load. The use of hollow beams decreases the structure dead load resulting in members with a small cross-section area. A comparison between the torsional performance of hollow and solid beams shows an impact of ST.F and SY.F with different lengths. Past research has explored the enhancement of adding ST.F on the performance of post-cracking torsional and the ultimate torsion strength [10-14]. Nevertheless, there are limited studies on the SY.F impact on the torsional features of the reinforced concrete beam (RCB) with fiber. The torsional performance of SY.F that reinforcing concrete under pure torsional pressure must, therefore, be tested utilizing