Figure 15 - uploaded by Rajib Kumar Biswas
Content may be subject to copyright.
![Effects of different aspect ratios of steel fibers on crack propagation: (a) MF15 (aspect ratio 125), (b) MF06 (aspect ratio 50) [65].](profile/Rajib-Biswas-2/publication/353368368/figure/fig1/AS:1048009097900032@1626876248132/Effects-of-different-aspect-ratios-of-steel-fibers-on-crack-propagation-a-MF15-aspect.png)
Effects of different aspect ratios of steel fibers on crack propagation: (a) MF15 (aspect ratio 125), (b) MF06 (aspect ratio 50) [65].
Source publication
![Effect of fiber percentage on setting times [42].](profile/Rajib-Biswas-2/publication/353368368/figure/tbl1/AS:1048009097871361@1626876248275/Effect-of-fiber-percentage-on-setting-times-42_Q320.jpg)
![Effect of fiber percentage on setting times [43].](profile/Rajib-Biswas-2/publication/353368368/figure/tbl4/AS:1048655893114884@1627030456647/Effect-of-fiber-percentage-on-setting-times-43_Q320.jpg)
Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of...
Similar publications
The performance of short basalt fiber bundles reinforced concrete (SBFBRC) is studied in depth through numerical simulation. Based on the data of the flexural test of basalt fiber-reinforced concrete with 0% and 0.2% content, the basalt fiber-reinforced concrete is established by ABAQUS. The validity of the model is verified by the existing test da...
Citations
... When the basalt fibers' volume ratio ranges from 1.5% to 2.5%, the amount of leached Cr and Zn increase. This can be explained by the fact that the basalt fibers can limit the cracking of HPC due to the cement hydration caused by heat and drying shrinkage [55]. Therefore, the amount of leached Cr and Zn from HPC with basalt fibers increasing from 0% to 1.5% is decreased by the added basalt fibers. ...
This paper aims to study the influence of the assembly units of CO2-cured iron tailings (IOT) and CO2-cured secondary aluminum ash (SAA) on the fresh high-performance concrete’s (HPC’s) slump flow and setting time. The mechanical properties including the flexural strength, compressive strength, the bonding strength and the dry shrinkage rate of the hardened HPC are measured. The amount of leached Cr and Zn after immersing in deionized water for 1 month~6 months is measured. The influence of the basalt fibers’ volume ratio and the aspect ratio of the high-performance concrete’s performance is considered. The scanning electron microscopy energy spectrums (SEM-EDS) are obtained. The results show that the slump flow and the setting time of fresh HPC are increased by the added CO2-cured SAA and IOT. The fresh HPC with 10% CO2-cured IOT and 20% CO2-cured SAA had the highest slump flow. The slump flow decreases in the form of cubic function with the placing time. The mechanical strengths and the dry shrinkage rate of HPC during the early curing ages (cured for 0.5 day~7 days) are decreased by the CO2-cured SAA and CO2-cured IOT, while the mechanical strengths at later curing ages (14 days~90 days) are increased by the added CO2-cured SAA and CO2-cured IOT. HPC with 10% CO2-cured SAA and 20% CO2-cured IOT shows the highest mechanical strengths. The amount of leached Cr and Zn is decreased by the CO2 cured SAA and IOT. The relationship between the mechanical strengths and the curing time coincides with the cubic equation. The basalt fibers with a volume ratio of 2% and aspect ratio of 1000 show the highest mechanical strengths, the lowest dry shrinkage rate and the least amount of leached Cr and Zn. CO2-cured SAA and IOT can improve the compactness of HPC’s hydration products. HPC with 10% CO2-cured SAA and 20% CO2-cured IOT shows the highest compact hydration products.
... Steel fibers prevent concrete cracks from forming and spreading, which eventually leads to stronger concrete (Kumar et al.; Ibrahim et al,) [50,51]. When incorporating steel fibers in accordance with ASTM C109/C109M-07 [45] and ASTM C39/C39M-10 standards [53], Kazemi and Lubell [54] saw a favorable result. ...
... It is worth that plain UHPFRC showed markedly shorter time at temperature peak than plain UHPC also accompanied by a reduction of tsp. That was not expected since other researchers (Biswas 2021) have found increasing setting time with increasing the fibers content in UHPFRC. One possible reason could be the role of water adsorption on the fibers surface, due to the high fiber content, leading to lower available water content in the pores. ...
Setting and hardening of ultra-high-performance concrete (UHPC) and ultra-high fiber reinforced concrete (UHPFRC) have been monitored with electrical conductivity in laboratory experiments with an equipment suitable for in-field remote sensing. Key parameters permitting to identify key stages during cement hydration could be determined. The electrical conductivity mildly changed during the fluid state, remaining at relatively high levels. During setting and early hardening, a sharp transition was observed toward much lower conductivity values. In the late-hardening further conductivity reduction occurred. The contribution of graphene has been investigated in those identified stages, showing both in UHPC and UHPFRC an effect to accelerate the fluid to solid transition and to mitigate the conductivity reduction in the late hardening stage. The role of fibers has also been investigated.
... Different parameters for steel fiber selection[26]-[28] ...
Precast concrete sandwich wall panels offer advantages such as design flexibility, ease of installation, cost-effectiveness, and energy efficiency due to the incorporated insulation layer, but regular concrete production has sustainability issues. This study aims to improve the sustainability of these panels by utilizing stone waste aggregates as a replacement for natural aggregates and supplementary cementitious materials as a partial replacement for cement. The panels were made with two concrete wythes reinforced with steel fibers and joined using basalt fiber-reinforced polymer (BFRP) connectors, with high-density expanded polystyrene (EPS) insulation (30 kg/m3) in between. Self-compacting concrete mixes with varying proportions of stone waste aggregates and supplementary cementitious materials were used. Full-scale wall panels were cast and subjected to flexural tests per ASTM standards, analyzing load-displacement curves, ultimate bearing capacity, and failure modes. The incorporation of steel fibers and stone waste aggregates resulted in substantial increases in failure load and flexural strength compared to controlled concrete panels, with the stone waste steel fiber panels exhibiting significantly higher maximum cracking loads and improved energy absorption and ductility. The inclusion of these sustainable materials, along with basalt fiber connectors and grooves in the EPS layer for mechanical interlock, prevented brittle failure modes and enhanced the composite action, leading to more ductile behavior under flexural loading. Utilizing sustainable materials like stone waste aggregates (100% replacement) and supplementary cementitious materials (30% replacement) in these panels can contribute to eco-friendly and efficient construction practices while maintaining adequate structural performance, paving the way for more sustainable building systems
... The observed increase in maximum load-taking capacity and reduction in damage near the joint core region with increasing aspect ratio aligns with previous studies. Longer and thinner steel fibers enhance the loadtaking capacity by filling voids in the matrix and dissipating energy more effectively through crack bridging mechanism 54,55 . This mechanism delays crack initiation and propagation, increases toughness, and enhances post-cracking performance of the matrix, as demonstrated in this research. ...
Brittle shear failure of beam-column joints, especially during seismic events poses a significant threat to structural integrity. This study investigates the potential of steel fiber reinforced concrete (SFRC) in the joint core to enhance ductility and overcome construction challenges associated with traditional reinforcement. A non-linear finite element analysis (NLFEA) using ABAQUS software was conducted to simulate the behavior of SFRC beam-column joints subjected to cyclic loading. Ten simulated specimens were analyzed to discern the impact of varying steel fiber volume fraction and aspect ratio on joint performance. Key findings reveal that a 2% volume fraction of steel fibers in the joint core significantly improves post-cracking behavior by promoting ductile shear failure, thereby increasing joint toughness. While aspect ratio variations showed minimal impact on load capacity, long and thin steel fibers effectively bridge cracks, delaying their propagation. Furthermore, increasing steel fiber content resulted in higher peak-to-peak stiffness. This research suggests that strategically incorporating SFRC in the joint core can promote ductile shear failure, enhance joint toughness, and reduce construction complexities by eliminating the need for congested hoops. Overall, the developed NLFEA model proves to be a valuable tool for investigating design parameters in SFRC beam-column joints under cyclic loading.
... This is not to say the mixture is not compactible, but that exterior vibration is necessary to achieve adequate compaction. Furthermore, this trend should only be expected from steel fibers of the same aspect ratio, as fibers of different type and aspect ratio impact fluidity differently [165]. ...
... Moreover, when comparing a zero percent dosage and two percent dosage of steel fibers a percent increase of 25%, 24.7%, and 22.5% occurred at one, seven, and 28-days respectively. These increases in compressive strength are caused by the steel fibers suppressing the formation of macro cracks and transferring stress to instead form microcracks, which better holds together the cementitious matrix resulting in higher compressive strengths [165]. Due to their significant improvement in compressive strength steel fibers are a critical material addition when trying to achieve ultra-high compressive strengths. ...
High Friction Surface Treatment (HFST) is a roadway remediation technique used to improve pavement's coefficient of friction, to enhance roadway safety. The application of HFSTs has repeatedly demonstrated the ability to significantly reduce crashes in both wet and dry conditions. Typically, epoxy-resins and calcined bauxite aggregate are used in HFST treatment. However, the high material costs and scarcity of calcined bauxite render this form of HFST an expensive and limited option for roadway rehabilitation. Therefore, the identification of alternative binders and HFST aggregates is needed for broad scale implementation. One potential alternative binder is Ultra-High-Performance Concrete (UHPC), a specialty cementitious material. UHPC is characterized by its high compressive strength (>120 MPa), enhanced toughness, high fluidity, and high bond strength. These properties of UHPC make it a potential alternative to epoxy-resins, however additional research is needed to assess the suitability of UHPC for HFST application. Previous research has shown that compared to natural aggregates, calcined bauxite was found to be a superior aggregate for HFST application, and therefore calcined bauxite will be used as the HFST aggregate in this study. In this study multiple sets of tests were conducted, to evaluate UHPC-based HFSTs. Initial testing focused on determining suitable materials for UHPC and how varying their inclusion rate impacted performance. From those results, the UHPC mixes were optimized using the Modified Andreasen and Andersen method for particle packing and tested across key HFST failure criteria. This testing provided proof that UHPC-based HFST is possible and identified shrinkage and bond strength as potential modes of failure. After identifying viable mixes, UHPC-based HFST overlays were created and tested under simulated traffic using multiple application methods. This process identified the use of intermixed calcined bauxite in UHPC, followed by the aggregate exposure using set retarders as an effective application method. In addition, the impact of varying intermixed calcined bauxite contents on the properties of UHPC was also studied. The testing on intermixed calcined bauxite contents determined that a calcined bauxite (CB)-to-cementitious materials (CM) ratio of 1.5 to 2.0 provided adequate bond strength while substantially reducing shrinkage. However, the shrinkage reduction was not enough to eliminate the risk of cracking and further testing to evaluate the impact of fibers on shrinkage using the thin-layer shrinkage test was conducted and found a significant increase in strength and a moderate reduction in shrinkage. Cumulatively, the findings from this study provide general guidelines on how to further develop UHPC-based HFSTs and compare the performance of UHPC-based HFSTs to traditional epoxy-resin-based HFSTs. This study identifies that UHPC-based HFSTs on concrete substrates managed to match or exceed the bond strength of the epoxy-resin-based HFST, whereas the UHPC-based HFST showed an inferior bond strength with asphalt substrate compared to resin-based HFST. Shrinkage mitigation techniques are needed to ensure that shrinkage of UHPC-based HFST does not result in cracking. Finally, it was determined that UHPC with intermixed calcined bauxite aggregate, exposed using set retarders, provided an exceptional frictional performance. Based on the findings from this study, UHPC-based HFST appears feasible, and field studies are warranted to assess long-term performance under true traffic conditions.
... Adding steel fibers improved mechanical properties like CS, FS, and toughness. However, it also decreased workability and increased setting time for UHPFRC (Biswas et al., 2021). ...
The performance of concrete is robust in compression but lacks tensile strength, making it brittle. Steel fibres are added to enhance concrete properties. These fibres play a crucial role in construction by improving structural performance, preventing cracks, and increasing ductility. The study investigated high-strength steel fibre-reinforced concrete (HSSFRC) with varying concrete strengths. Three high-strength concrete grades (70 MPa, 80 MPa, and 90 MPa) and different water-cement ratios (WCR) (0.25, 0.30, and 0.35) were studied. Hooked-ended 50mm steel fibres were added at content levels of 0.25%, 0.50%, 0.75%, and 1.00%. As steel fibre content increased from 0.25% to 0.75%, the compressive strength (CS) improved by 3.37%, 7.29%, and 10.54%. At the same time, the split tensile strength (STS) increased by 20.86%, 24.07%, and 26.74%. Similarly, the flexural strength (FS) increased by 19.87%, 23.12%, and 25.82% for a WCR of 0.25 in 70 MPa grade of concrete. However, adding 1.0% steel fibre led to decreased mechanical properties. The optimal steel fibre content across all concrete mixes was 0.75%. Mechanical properties weakened with higher WCR (0.25, 0.30, and 0.35). Additionally, regression analysis explored the relationships between CS, STS, and FS in the concrete mixes. The comparison between the test results and the regression analysis was carried out alongside the previous empirical formulas. Remarkably, the empirical formulas exhibited strong alignment with the experimental findings.
... The steel fibres enhance the axial load-carrying capacity of the FECC specimens, as represented in Figure 8. Additionally, the SF prevent minor cracks and concrete cover spalling [35][36][37][38][39][40]. The addition of 0.6% steel fibres leads to an improved axial load-carrying capacity of 4.82%, 4.35%, 4.06%, and 4.34% for the following FECC specimens: HSC80-FECC-SF0.6-100, ...
Currently, fully encased composite columns (FECCs) and high-strength concrete (HSC) are widely used in the construction industry to build durable structures. Specifically, HSC is primarily employed in high-rise buildings, highway bridges, and tunnels. This study examined eight FECC specimens with 200 mm × 250 mm × 1000 mm dimensions. Four FEC columns were considered control specimens, while the remaining four were cast with the optimum content of 0.60% Steel Fibre (SF). These specimens were fabricated with two different lateral reinforcement spacing: 100 mm and 80 mm. All specimens were tested under axial loading using a 500 T capacity frame. The main objective of this study was to evaluate the axial load-carrying capacity, axial load-deformation behaviour, ductility, stiffness, energy absorption capacity, and mode of failure of all FECC specimens. Adding 0.6% steel fibre and reduced lateral reinforcement spacing enhanced the specimens axial load-carrying capacity, ductility, and energy absorption capacity. The steel fibre was crucial in preventing concrete cover spalling and cracks on the specimens. Experimental test results for the FECC specimens were compared to various codes, including IS: 456 – 2000, JGJ 138-2016, and EN 1994-1-1. The present results were compared to previously published data and evaluated using the same codes. According to the experimental and analytical findings, the prediction results from JGJ 138-2016 and EN 1994-1-1 were highly correlated with the experimental results. EN 1994-1-1 is recommended for developing two proposed methods, which were also compared to the experimental test results. These proposed methods demonstrated good agreement with the experimental outcomes, with mean values of 1.08 and 1.06, standard deviations of 0.04, and coefficients of variation of 3.54% and 3.53% for proposed methods 1 and 2, respectively.
Keywords:
Fully encased composite columns; High strength concrete; Peak ductility; Energy absorption capacity; Steel fibre
... For example, reductions of 19 % and 31 % in flow diameter were observed for SR and CS3 mixtures compared to R and C3 mixtures, respectively. It is well-reported in the literature that the addition of steel fibers decreases the workability of UHPC/UHPM owing to their stiffness [72,73], and similar results were observed in this study. The reduction in flow diameter was more prominent for mixtures incorporating both steel fibers and SWCNT than mixtures incorporating only steel fiber or SWCNT. ...
For security amenities and key infrastructure, construction materials with extraordinary mechanical, durability, and electromagnetic interference (EMI) shielding performance are essential. This study investigates the EMI shielding performance of ultra-high performance mortar (UHPM) incorporating single-walled carbon nanotubes (SWCNT) and steel fibers. Currently, no such work is present in the existing literature. Eight mixtures were prepared with varying SWCNT dosages (0%–0.03 % by weight of cement) and steel fiber additions (1.2 % of the volume of the UHPM mixture). The performance of UHPM incorporating SWCNT and steel fibers was evaluated through flow diameter, compressive strength, flexural strength, Schmidt hardness, ultrasonic pulse velocity, EMI shielding performance, and scanning electron microscopy analysis tests. It is observed that increasing the SWCNT content enhances the compressive strength, flexural strength, ultrasonic pulse velocity, and Schmidt hardness of UHPM. The addition of steel fibers further enhances compressive (up to 22 %) and flexural (up to 92 %) strengths. In terms of the transmittance behavior, the improved EMI shielding performance of UHPM with the increasing SWCNT content is observed prominently at high electromagnetic frequencies (i.e., 2500 MHz–5100 MHz). However, the improved shielding performance is observed to be quite low, limited to 10 dB. Moreover, combining steel fibers and SWCNT enhances the EMI shielding performance of UHPM in terms of the transmittance behavior. As a result, UHPM incorporating SWCNT and steel fibers behaves as an absorbent material, shielding a significant amount of energy, approximately 45 dB, at a frequency of 5000 MHz. Based on the results, UHPM incorporating SWCNT and steel fibers can be used effectively as EMI shielding material. The findings of this study will enhance the practical applications of UHPM incorporating SWCNT and steel fibers.
... Steel fibers tend to interlock, in turn affecting mix workability. Biswas, et al. [47] found that the aspect ratio and quantity of steel fibers greatly influence cement flow. Figure 6 shows the various properties of the UHPFRC samples. ...
Ultrahigh-performance fiber-reinforced cement-based composite (UHPFRC) made with waste derived from scrap tires and oil refineries was tested in this study. The UHPFRC sample exhibited a maximum compressive strength of about 189 MPa at the end of 28 days. Steel fibers were recovered from scrap tires and were added up to 3% by volume in the UHPFRC samples. Such additions reduced cement flow by 11% but improved compressive strength by 21%. The equilibrium catalyst particles (ECAT) disposed of by oil refineries were used in amounts of up to 15% by weight as a replacement for cement in such UHPFRC samples. These aluminosilicate materials are spherical in shape and have a porous microstructure, which was found to reduce the cement flow by absorbing more free water onto their surfaces. They also reduced the heat and strength developments at early stages. However, the total cost of the final cement-based mixture and associated CO2 emissions were reduced by up to 7% and 15% due to the inclusion of the ECAT particles. These findings help to optimize the ECAT and recovered steel fibers in the UHPFRC mix design, and such waste valor-ization strategies can help achieve the goal of becoming carbon neutral.
