Papers by Keyword: Steel Fiber

Abstract: Reinforced concrete remains vulnerable to cracking under service loads, which threatens structural integrity and serviceability. Improving the flexural strength and crack resistance of reinforced concrete in an environmentally sustainable manner has become a critical concern in modern construction. Despite being a primary construction material, reinforced concrete remains susceptible to cracking, which can significantly compromise structural integrity. This study aims to evaluate the enhancement of flexural performance and crack control mechanisms in reinforced concrete beams through the incorporation of Ground Granulated Blast Furnace Slag (GGBFS) and 1% steel fiber by concrete weight. Two beam variations were tested: one without fibers and one with steel fiber, both designed with a water-cement ratio of 0,4. Flexural tests were conducted up to the yielding condition to assess load capacity, deflection, flexural stress, and crack patterns. The results showed that the beam with steel fiber exhibited a 24% higher maximum load capacity and a 17% greater deflection at yield compared to the beam without fiber. The flexural stress increased from 10,69 N/mm² to 13,31 N/mm². The load deflection curve indicated a more stable deformation response and improved load resistance up to the yield point. Moreover, the addition of steel fiber delayed crack propagation and enhanced resistance against crack development. Overall, the incorporation of steel fiber proved effective in improving strength and crack resistance in the flexural elements of reinforced concrete. These findings support the development of sustainable structural concrete for future applications.

Abstract: The results of research on the mechanical properties of concrete with the addition of steel fibers of three different types - anchored, flattened and waved - are presented. To study the influence of steel fiber on the mechanical characteristics of fiber concrete, standardized samples were made and the following tests were carried out: cubes for chipping and compression; compression prism; figure eights for stretching; prism for tension in bending. Different types of steel fiber show unequal increases in strength. The most profitable from this point of view is the addition of anchor fiber to concrete, the least - wave fiber. But the presence of any of the considered steel fibers in the composition of the mixture significantly increases the strength of the sample. The obtained values of tensile strength when splitting the cubes, depending on the type of fiber, differ from the control concrete samples, respectively: for the anchor fiber by 22.82%, for the flattened fiber – 21.84%, for the wave fiber – 9.59%. The presence of fiber reinforcement has a positive effect on the strength during compression tests of cubes: by 13.01% for anchor fiber, 13.84% for flattened fiber, and 11.47% for wave fiber. It was found that the load-bearing capacity of steel-reinforced concrete under compression practically does not depend on the type of fiber, but the very presence of steel fiber in the concrete mixture from which the prisms were made increases the strength of the sample by an average of 11% compared to concrete prisms. In eight-figure tensile tests, the strength of concrete reinforced with wave fiber fiber gave an increase of 4.1% and 4.4% for reinforcement with anchor fiber. Tensile testing of prisms during bending using steel fiber on average increases the load at the beginning of cracking by 40%, and the load-bearing capacity by 64%. In addition, the type of failure of the sample changes from brittle to viscous.

Abstract: Environmentally friendly building materials known as geopolymers are made by combining high-alkalinity solutions with powder components rich in silica and alumina. It has long been known that adding fibers to the matrix phase can improve the mechanical characteristics of composite materials made for various uses. Among these are SIFCON composites, which are made by first inserting the fibers into the mold and then packing the gaps between the fibers with an extremely fluid matrix phase. The present study looked over the mechanical properties and efficiency of cement-based and geopolymer-based slurry infiltrated fiber concrete SIFCON and G-SIFCON. In the current study, for the production of both SIFCON and G-SIFCON composites, 7.5% steel fiber by volume fraction was utilized for this purpose. Therefore, sets of concrete specimens including cylinders and prisms were prepared and tested in accordance with standard specifications. The results obtained from the conducted tests prove that the 7.5% of steel fiber ratio can be used effectively to improve the mechanical performance of G-SIFCON and SIFCON composites. Furthermore, the cement-based SIFCON can be effectively replaced by fly ash-based geopolymers. Also, for composites made with fly ash-based geopolymers (G-SIFCON), high compressive strength slurries may exhibit more enhancement in mechanical properties than normal strength slurries.

Abstract: This study aims to investigate the effect of integrating red mud (RM) waste and different types of steel fibers on the fracture toughness characteristics of self-compacting concrete (SCC). A total of 24 specimens consisting of notched SCC beams with various steel fibers (measuring 100 × 100 × 500 mm) are subjected to a three-point bending test. This study examines five various fiber types characterized by varying shapes and aspect ratios. These fiber types include the hook-end fiber with lengths of 60 and 30 mm, the long straight fiber with lengths of 21 and 13 mm, and the flat-end fiber. Six concrete mixtures, each incorporating fibers with 1% of the volume percentage, are examined. RM is used at a replacement rate of 20% of the mass of cement. Another objective of the study is to analyze the mechanical and fresh characteristics of concrete. The findings indicate that the incorporation of steel fiber has an adverse effect on the fresh concrete characteristics of SCC. The presence of steel fiber results in enhanced mechanical properties, peak loads, and deflection at the point of failure, in addition to an increase in the crack mouth opening displacement. The fracture toughness of SCC mixtures is also influenced by the presence of steel fiber.

Abstract: This investigation inspects the concurrent influence of steel fibers with different materials such as Fly Ash(FA), Silica Fume(SF) and aggregates on the mechanical behaviour of geopolymer concrete (GPC) mixes. A range of 8 to 16 molar NaOH molarities variation was observed in the experimental work. Sodium hydroxide molar (NaOH) and sodium silicate solution (NaOH) were utilised as alkaline activators in proportions of 1, 1.5, and 2 (Na₂SiO₃/NaOH). Steel crimped fibers having aspect ratio of 60 were added in the geopolymer concrete. Geopolymer concrete properties considering type of fly ash, the quantity of fly ash, silica fume, the content of fine aggregate and coarse aggregate, effect of sodium hydroxide concentration, content of sodium silicate solution and inclusion of 0.2% of steel fibers in the geopolymer concrete are analyzed.

Abstract: Self-compacting concrete is one of the major advancements in construction. The purpose of this investigation is to evaluate how self-compacting concrete with steel fibres and the appropriate superplasticizer for M30 grade is presented. Effects of combining quartz flour 0 %,5 %,10 %, 15 %, 20 % and steel fibre 0 %,0.25 %,0.50 %,0.75 %, 1 % in varying amounts adding with cement. An experimental study was conducted on the fresh and hardened states of concrete. The optimal combination of quartz flour and steel fibre reinforced concrete was discovered while comparing the mixes to conventional concrete. Quartz flour with ultra-fine particles can fill holes and improve permeability resistance as well as bonding. As a result, utilizing this combination of quartz flour in self-compacting beams, studies explored the strength and ductile properties of normal and ductile details in beams, as well as comparing them to standard self-compacting concrete. Because self-compacting concrete is brittle by nature, adding fibres increases its tensile strength and ductility. Mineral admixtures improve the flow qualities.

Abstract: The feasibility of determining the extent of damage in fibered concrete after being subjected to high temperatures, using non-destructive methods was investigated. The study was conducted on four concrete mixtures with different fiber types. The specimens underwent a curing process at 23 °C before being exposed to different high temperatures of 400 °C, 600 °C, and 800 °C. After cooling to ambient temperature, various non-destructive tests including ultrasonic pulse velocity testing (UPV), the resonance frequency test (RF), the dynamic modulus of elasticity (Ed), the thermal conductivity test (λ), and Schmid Rebound Hammer (SRH), were performed. To evaluate the sensitivity of non-destructive techniques to assess the damage of fiber-reinforced concrete, the Lemaitre coefficient was used as a variable to describe the extent of the damage. The results indicated that the highest damage levels were obtained through the modulus of elasticity technique regardless of the type of concrete mixture or temperature exposure. There was also a potential agreement found between thermal and ultrasonic methods in evaluating the thermal degradation of concrete.

Abstract: Fiber reinforced concrete is a commonly used material to cater for the shortcomings of concrete, such as low tensile strength, brittleness, and rapid crack propagation. This paper presents an experimental study on the mechanical properties of the hybrid (steel-kenaf) fiber added into concrete mixture. Two types of fibers, namely hooked-end steel fiber and kenaf fiber were considered. A control specimen without fibers was used to compare with fiber reinforced concrete mixture considering 1% and 2% volume fraction. Mechanical properties, i.e., workability, compressive strength and flexural strength, were investigated. In this study, the kenaf fibers were treated by 6% concentration of Sodium Hydroxide (NaOH) through immersion in the laboratory for 24 hours. The results showed that the addition of hybrid fiber improves the performance of compressive strength and flexural strength of the concrete. Specimens with 2% hybrid fibers show the best flexural performance. Moreover, an increase in volume fractions of steel fibers leads to an increase in the compressive and flexural strengths of concrete. In addition, specimens with steel-kenaf hybrid fibers exhibit a better failure behavior than specimens without fibers.

Abstract: Demolish existing structures for better economic gains, functional and structural performance, and non-availability of land or disposal sites in nearby areas of all major cities worldwide turned as a significant reason for the crushing demolished concrete instead of using it as landfill. Research work aimed at arriving Recycled Concrete (RC) with the help of two materials, i.e. Steel Fibers (SF) and Styrene-Butadiene Rubber (SBR) latex, as additives to improve strength parameters of it. SF and SBR added in RC to examine & strengthen and termed as Steel Fiber Reinforced Polymer Modified Recycled Aggregate Concrete (SFRPMRAC). For this purpose, 198 cubes each of M20 (trial-1) and M25 (trial-2) cast separately to check compressive strength and its stress-strain behaviour for Natural Concrete (NC), RC & SFRPMRAC. The volume fractions of SF added 0.5%, 1% & 1.5% m³ of concrete and dosages of SBR latex varied from 2.5%, 5% and 7.5% by cement weight for preparation of cubes made of RC. From experimental results, SFRPMRAC with SF volume fraction of 1% m³ of concrete and 5% by cement weight provides an improvement in compressive strength by 8.62 % & 10.73 % for trial -1 and 11.51 % & 12.57 % for trial - 2 at 28 & 90 days when compared with NC. Compression stress-strain behaviour for SFRPMRAC with SF 1% m³ of concrete and 5% by weight of cement shows higher strain values at the peak stress. SFRPMRAC arrests the sudden drop of load due to co-matrix bond formation between SF and SBR in a linear direction compared to a similar NC & RC mix for both trials. It reflects significant improvement and approval of compressive strength for the desired purpose.

Abstract: Concrete members are reinforced by steel fibers to overcome their brittle nature. This paper is focused on the effect of percentage of fiber and the maximum aggregate size on mechanical properties of concrete samples such as compressive and tensile strengths, and ductility. The mean values of these quantities show that by increasing the reinforcement content to 0.66% and the size to 12.5 mm, there is a dramatic improvement on properties of samples. Also, they demonstrate that the size of coarse aggregate has more effect on improvement of the quantities in comparison to steel fiber content and changing the size and fiber content has more effects on ductility than mechanical properties. Statistical approach which considers standard deviations of experimental data, confirms that the gravel regardless of fiber content, leads to the highest improvement on properties with size of 12.5 mm. But the results show for volumetric steel fiber without considering aggregate size, is 0.33%. This clearly indicates the effect of data scattering on mean values of mechanical properties and ductility.