Steel Fiber Concrete Research Articles

Study of strength related resources of hybrid fiber reinforced concrete (HFRC) and energy absorption capacity (EAC)

Cement Concrete is the most widely used building material for all civil engineering applications due to its well-known benefits. However, its limited tensile strength is a concern. It understands, clearly that fiber reinforcement is finest and adaptable way to improve the post cracking tensile strength and energy absorption capacity during under diagonal split tension and under axial compression. In the present investigation study steel and polyester fibers remained in various volume fractions. Control concrete mixture was made with Ordinary Portland Cement (OPC), fine and coarse aggregate along with flyash, silicafume and high range water reducing admixtures. With no change in the constituents of concrete steel fiber reinforced concrete specimens were made with hooked end steel fibers of aspect ratio 80 vol fraction being 1.0%, 1.25% and 1.5%. Similarly, polyester fiber reinforced concrete specimens were made with 12 mm synthetic polyester fibers at 3%, 4% and 5% volume fraction. All the specimens were cured for 28 days and the fresh concrete was tested to ensure the workability by conducting slump test. In comparison to the control concrete, all the fiber reinforced specimens containing single and hybrid combinations exhibited significant improvement in tensile and flexural strength properties. Uni axial compression loading condition was adopted for all the 100 mm × 200 mm cylindrical specimens. In both the loading conditions load distortion curves stood plotted and the areas under the curves were calculated as a measure of energy absorption capacity. Compressive strength as compared to control concrete was enhanced due to polyester fiber, steel fiber, in that order. Split tensile strength has been significantly improved due to polyester hybridisation with steel fibers. Hence the hybridisation has improved the necessary belongings of concrete like split tensile strength and toughness significantly.

Development of Damage Type Viscoelastic Ontological Model for Soft and Hard Materials under High-Strain-Rate Conditions

By improving the ZWT model, a principal structure model applicable to both soft and hard materials under dynamic loading conditions was obtained. Dynamic mechanical experiments were conducted using SHPB to obtain stress–strain curves for coal rock and foam concrete. The ZWT intrinsic model was simplified according to the dynamic impact characteristics of concrete, and the intrinsic model was established by introducing macroscopic damage quantity D and correction factor δ. The stress–strain curves of coal rock, foamed concrete, steel fiber concrete, granite, lightweight foamed concrete, and EPS concrete at different strain rates were used to validate the present constitutive model and prove the correctness of the model.

A Comparative Study on the Confinement Models of High-Strength Steel Fiber Concrete

Since the last four decades, the behavior of concrete contains of steel fiber, or often called steel fiber concrete, with a wide range of compressive strength has been carried out. Generally, the results of the experimental program produced a material which has a more ductile compared with normal concrete or concrete without fiber. Due to the ductility properties of the material, it is very suitable for use as an earthquake-resistant structural material. At the same time, the behavior of high-strength steel-fiber concrete has also investigated, one of which is about confined high-strength steel-fiber concrete. Analytical models of confined high-strength steel fiber concrete have been developed in various preliminary studies, with their characteristics derived based on the experimental results. Therefore, this research evaluated the models of confined high-strength steel-fiber concrete proposed by Mansur et al., Hsu and Hsu, and Paultre et al. The evaluation includes stress-strain behavior, strength enhancement of confined concrete (f'cc/f'co) or K value, the increase in confined concrete strain (ε'cc/ε'co), and strain of confined concrete when the stress has dropped by 50 percent against its unconfined strain (εcc50/εc50). The comparison method was carried out using a statistical approach and stress-strain simulation. Evaluation results showed significant predictive differences in confinement models in terms of post-peak behavior and parameters ε'cc/ε’co and εcc50/εc50. Prediction of confinement models on the value of f'cc/f’co to the experimental results has a coefficient of variation above 10%. The result further showed that a modified model of confined high-strength steel-fiber concrete was proposed and able to simulate the stress-strain behavior.

Investigation on the use of reclaimed asphalt pavement along with steel fibers in concrete

Poor disposal and handling of asphalt material in construction activities has a great effect on the environment. Despite the use of asphalt material in other activities, a high percentage of it is poorly handled in Uganda. For this, the present study aimed to investigate the mechanical performance of reclaimed asphalt pavement (RAP) along with steel fibers in concrete and the variation of mechanical behavior concerning different curing times with the optimal RAP aggregate-substitute ratio. The result showed that the mechanical and physical properties of the fine and coarse aggregates used suited the replacement when compared with BS EN standard. Workability of fresh concrete is reduced as the percentage RAP increases in the mixture. This reduction was caused due to the asphalt mortar coating on the RAP aggregates, dirt particles and the irregular shape of aggregates. The compressive strength increases and decreases afterward with the increase of the percentage RAP replacement ratio. This occurred due to the presence of oils in the bitumen and weak bond between the asphalt binder coating around the RAP aggregates. When the steel fibers increase, the split strength increases along with curing time. A maximum savings of 6.13% of RAP was accomplished by incorporating 60% RAP replacement mix. For the Uganda scenario, this work serves as a guide for excess RAP application in construction activities. Using reclaimed asphalt materials provides a long-term solution for reducing the cost of materials and end-of-life materials disposal in the landfill.

Experimental study on basic mechanical properties of recycled steel fiber reinforced concrete

Abstract Recycled steel fiber (RSF)-reinforced concrete is not only an innovative research trend in the field of civil engineering materials, but also a new type of civil engineering composites under the trend of low-carbon development. This article deals with the experimental study of applying waste steel fibers to form recycled steel fiber concrete (RSFC). The main materials in this study are RSF, coarse and fine aggregate, fly ash, silica fume, and water reducer agent formed by machining surplus materials as the main materials. Three types of concrete were prepared. They were normal concrete, primary steel fiber concrete (PSFC), and RSFC with six different volume contents. The slump and air content of the three types of concrete are compared and analyzed. Then, the effects of the volume content of RSF on the cube compressive strength, splitting tensile strength, flexural strength, and axial compressive strength of RSFC are studied. Finally, the toughness of RSFC is discussed. The test results show that with the increase in the volume content of RSF, the slump of RSFC is significantly reduced, the compressive strength, tensile strength, and flexural strength are enhanced, the increase in tensile strength and flexural strength is significantly higher than the cube compressive strength, and the RSF has an obvious inhibitory effect on the development of concrete cracks which can obviously enhance the ductility and toughness of the concrete.

UPGRADING THE PERFORMANCE OF DEFECTED BEAMS BY USING SLURRY INFILTRATION FIBER-REINFORCED CONCRETE AS A STRENGTHENING SOLUTION

One of the ways to increase the service life or upgrade the concrete buildings is by strengthening and repairing techniques. There are many methods of strengthening, such as using slurry infiltration fiber-reinforced concrete (SIFCON). This study cast eight normal reinforced concrete beams of 100 × 150 × 1000 mm. Seven are pre-loaded to 60% of their ultimate load, and the eighth is loaded to its ultimate load. Six beams are repaired with fresh and precast SIFCON layers in different configurations (bottom and jacketing). However, for comparison reasons, two beams are repaired with carbon fiber-reinforced polymer (CFRP) and steel fiber concrete. All beams are tested under a two-point flexural load. The parameters (ultimate load, ductility, toughness, stiffness, crack width, residual strength, and mode of failure) are investigated. The purpose of the study is to use a compatible cement-based material with new techniques for strengthening or repairing concrete members. The results showed that the new techniques significantly improved the behavior of the pre-loaded beams, and SIFCON layers (fresh or precast) could compensate for the failure in the steel reinforcement and be used as external reinforcement.

An Experimental Investigation on the Steel Fiber Concrete by Partial Replacement of Tio2 and Quartz Powder

Concrete is a building material widely used in the world for every construction project, and this construction projects consists of every possible challenge in terms of durability, exposure to various reactive substances and at a place where concrete needs to be high strength. the concrete is a mixture which is of heterogeneous aimed to solidify and produce strength based on the quality and composition of materials used in the concrete. in this study we are performing an experimental investigation to see whether there is any possible increase in the strength of nominal concrete to change to high strength concrete, In order to achieve this high strength we have used materials like steel fibres, TiO2 as partial replacement for cement, quartz powder as partial replacement of fine aggregate. We have performed several tests on materials, fresh concrete, and hardened concrete. We have also reviewed the previous works of the researches performed on the similar projects with the related materials. we have used a varied percentages of material ratios as 10%, 20%, 30%, 40%, 50% of quartz powder partially replacing fine aggregate, and 0%, 0.5%, 1.0%, 1.5% of TiO2 as partial replacement of cement, and 0%, 0.5%%, 1%, 1.5%, 2% of steel fibres addition to concrete.

Stability Control of Slopes in Open-Pit Mines and Resilience Methods for Disaster Prevention in Urban Areas: A Case Study of Fushun West Open Pit Mine

During the century-long mining process of the Fushun west open pit, slope slippage and deformation caused varying degrees of horizontal deformation, uneven settlement, and ground cracks on the surface of the urban areas, which caused a certain degree of damage to buildings and infrastructure and affected the livings of residents in the surrounding communities. In this study, a set of building reinforcement and community resilience enhancement methods that can resist slope deformation was proposed to improve the ability of urban areas to cope with slope geological hazards and emergency response. The main research contents included: Firstly, this paper systematically analyzed the deformation mechanism of the dip sloping and the inverse dip sloping section of the open pit mine, which was based on the field measured data and simulation calculation results. In other words, the horizontal deformation of the stratum in the dip sloping section was dominant, while the stratum in the inverse dip sloping section was prone to ground cracks and uneven settlement. In view of this, three surface deformation characteristic subdivisions of the surrounding urban area were proposed. In addition, a study on the damage characteristics of buildings with different types of foundations and structures under the influence of side slope deformation were carried out, and the anti-deformation reinforcement measures for load-bearing members mainly based on steel fiber concrete, carbon fiber materials and profile steel were proposed. Finally, a three-level disaster emergency setting system for urban areas around open pit mine was established, and the disaster prevention and resilience enhancement strategy for build and unbuilt the communities around the side slopes was constructed. The study aims to provide technical support to the overall resilience and response of the urban communities adjacent to open-pit mine slopes against consequent geological hazards and emergencies, thereby promoting sustainable urban development.

Research and Statistical Analysis on Impact Resistance of Steel Fiber Expanded Polystyrene Concrete and Expanded Polystyrene Concrete.

Steel fiber foamed concrete (SFFC) combines the impact resistance of steel fiber concrete (SFC) and the energy absorption characteristics of foamed concrete (FC), and it has brought attention to the impact field. Using the mechanical properties of SFFC expanded polystyrene concrete, we prepared (EPSC) specimens with 10%, 20%, 30%, 40%, 50% by volume of expanded polystyrene (Veps), and steel fiber expanded polystyrene concrete (SFEPSC) specimens by adding 1% steel fiber (SF) based on the EPSC in this study. The relationship between compressive strength, the Veps and apparent density was revealed. The relationship between the first crack and the ultimate failure impact of SFEPSC specimens was obtained by a drop-weight test. The impact resistance of SFEPSC and EPSC and the variation law of Veps were studied by mathematical statistics. The log-normal and the two-parameter Weibull distributions were used to fit the probability distribution of impact resistance of the SFEPSC and EPSC specimens. Finally, both types of specimens’ destruction modes and mechanisms were analyzed. The mechanism of the EPS particles and the SFs dissipating impact load energy was analyzed from the energy point of view.

Improving RC Beam-Column Joints Characteristics Using Different Reinforcement Details

This paper aims to study the effect of concrete confining using a new style of internal closed stirrups and longitudinal steel bars along with the middle third of the beam length of the beam-column joints. Also, the influence of concrete compressive strength was investigated using three types of concrete normal strength concrete (NSC), high strength concrete (HSC), and steel fiber concrete (SFRC). Nine reinforced concrete specimens with the same dimensions are divided into three groups according to the concrete type with different reinforcement details in the middle third of the specimen’s length. Four specimens with (NSC) represent the first group, while three specimens consist in the second group with (HSC). Steel fiber of 2% was used in two specimens of the third group (SFRC). The test results showed that using additional reinforcement steel bars as a closed stirrup arranged about the neutral axis improved the flexural strength and enhanced the load-carrying capacity for the reinforced concrete joints. The ultimate capacity of the joints increased by a range (34 to 50) % more than the control specimen. The ultimate strength was also increased for the specimens due to using high-strength concrete with a range (of 13 to 66) % compared with the specimen of normal compressive strength.

Mechanical Properties of Plastic, Steel, Organic Fibre Concrete: A Review

The mechanical properties of fibrous concrete reviewed in this research are flexural tensile, compressive, and split tensile strength. This paper is a review of many researchers on plastic, steel, and organic fiber concrete. The plastic fiber reviewed in this paper is a concrete mixture with mineral water glass waste with a volume fraction of 0.25% and L/d 37.5; steel fiber is the straight type while organic fibrous fiber is coconut husks, jute, the leaves of palm oil plants, sisal, hemp, banana leaves, pineapple leaves, bamboo bark, horse dung, rice straw, and gelam -bark. The performance of the three mechanical properties of non-fibrous concrete in each study is calculated in percentage. The mixtures that have superior mechanical properties are 0.5%, 2% steel-fibrous concrete (St0.5 and Sj2), 2% with aspect ratios of 75 and 50 (Ss0.5), 0.6% bamboo-bark fibrous concrete (B0.6) and 0.4% gelam -bark fibrous concrete (G0.4). The St 0.5 and Ss 0.5 showed increased tensile strength in the splitting test, but the increase for St 0.5 of the compressive strength was below B0.6 and G0.4. The B0.6 shows an increase in the splitting test of 45% while G0.4 shows an even increase of ± 7.5% in the three mechanical properties. Flexural tensile strength is not a function of compressive strength. The reduction in the level of ease of mixing in gelam bark fibrous concrete (G0.4) is the lowest compared to bamboo fibrous concrete with a volume fraction of 0.6 and steel-fibrous concrete. The flexural strength and compressive strength of plastic-fiber concrete are 2.1% and 4.7% higher, respectively than non-fiber concrete. The addition of plastic fiber is easier to mix than the addition of steel fiber. Keywords: concrete, fiber, mechanical properties, organic, plastic, steel DOI: 10.7176/CER/14-4-04 Publication date: June 30 th 2022

A [formula omitted]-function for inhomogeneous random measures with geometric features

This paper introduces a K-function for assessing second-order properties of inhomogeneous random measures generated by marked point processes. The marks can be geometric objects like fibers or sets of positive volume, and the presented K-function takes into account geometric features of the marks, such as tangent directions of fibers. The K-function requires an estimate of the inhomogeneous density function of the random measure. We introduce parametric estimates for the density function based on parametric models that represent large scale features of the inhomogeneous random measure. The proposed methodology is applied to simulated fiber patterns as well as a three-dimensional dataset of steel fibers in concrete.

Multilateral Assessment of Anchorage Bond Characteristics in Steel Fibre Reinforced Concrete.

Anchorage to concrete is a recurring application in construction. For such applications, bonded anchors, formed by means of a polymer adhesive injection into a borehole, are a widely used product due to their flexibility in regards to the construction logistics and positioning of the attached element as well as high load capacities. At the same time, fibre-reinforced concrete is the material of choice for many engineering applications where anchors have to be installed. Moreover, the use of steel fibre-reinforced concrete is likely to increase, since it now falls in the scope of the second-generation Eurocode 2 (exp. 2023). Therefore, the condition of the anchor installation borehole—mainly the roughness and grip of its internal surface—is known to play a critical role in the stress transfer from the attached component, through the fastening and into the concrete, and, hence, to the load-bearing performance. At the same time, drilling through the steel fibre reinforcement, along with the accelerated wear of the drilling tools, can in turn influence the borehole’s roughness and the overall installation quality. Furthermore, steel fibre may lead to an additional local stiffening of the concrete where the anchor is installed. These complex elements are discussed herein on the basis of multiple tests on anchors in plain and steel fibre concrete, as well as numerical analyses. The results indicate particular aspects of bonded anchor design and product certification for different polymer-based construction adhesives.

Research on the Construction of Steel Fiber Concrete in the Lining Segment of Shield Tunnel

Research on the Construction of Steel Fiber Concrete in the Lining Segment of Shield Tunnel

Sustainability of Using Recycled Steel Fibers in Concrete

Sustainability of Using Recycled Steel Fibers in Concrete

Erratum for “Effect of Adhesive through Pilot Pull-Out Tests on Handcrafted Headed Studs Postinstalled in Steel Fiber Concrete” by Aaron Kadima Lukanu Lwa Nzambi, Jeandry Bule Ntuku, and Dênio Ramam Carvalho de Oliveira

Erratum for “Effect of Adhesive through Pilot Pull-Out Tests on Handcrafted Headed Studs Postinstalled in Steel Fiber Concrete” by Aaron Kadima Lukanu Lwa Nzambi, Jeandry Bule Ntuku, and Dênio Ramam Carvalho de Oliveira

Research of Strength, Frost Resistance, Abrasion Resistance and Shrinkage of Steel Fiber Concrete for Rigid Highways and Airfields Pavement Repair

High-early strength fiber-reinforced concretes are effective materials for the full depth repair of rigid highway and airfield pavements. A comprehensive study was carried out on the influence of the amount of steel anchor fiber and hardening accelerator on properties that are important for repairing concrete. A two-factor experiment was carried out, in which the influence of the hardening accelerator and fiber dosages on the strength, frost resistance, wear resistance and shrinkage of repaired steel-fiber-reinforced concrete for rigid pavements was studied. The investigated concretes contained 400 kg/m3 of cement and polycarboxylate plasticizer in the amount of 1.2% of the cement content. It has been established that the optimal concrete compositions are with the amount of Sika Rapid 3 hardening accelerator from 1 to 2% of the cement content and the steel fiber amount from 60 to 90 kg/m3. Optimal fiber-reinforced concrete compositions have a reduced shrinkage during hardening, and at the age of 2 days they have a compressive strength of at least 55 MPa and a flexural strength of at least 8.5 MPa. At the design age, the fiber-reinforced concrete compressive strength is 85–90 MPa, its flexural strength ranges from 15.5 to 17.5 MPa, it has a frost resistance of F200 and abrasion not higher than 0.24 g/cm2. These properties ensure the high durability of the repair material.

Mechanical, Durability and Corrosion Properties of Basalt Fiber Concrete

The effect of using basalt fibers on the fresh, mechanical, durability, and corrosion properties of reinforced concrete was investigated in this study. The study was performed using different basalt fiber volume fractions of 0.15%, 0.30%, 0.45%, and 0.50%, while two different water/cement (w/c) ratios of 0.35 and 0.40 were utilized. The results were compared to conventional concrete (PC) as well as steel fiber concrete (SFC) with 0.30% and 0.50% steel fibers volume fractions. An extensive experimental program of 336 samples was conducted in four stages as follows: testing for fresh properties included slump and unit weight tests; mechanical properties testing included compressive strength tests, split tensile strength tests, flexural strength tests, and average residual strength tests; durability testing included unrestrained shrinkage and surface resistivity tests; and a Rapid Macrocell corrosion evaluation test for corrosion properties. The test results showed that the use of basalt fibers reduces slump values as the fiber volume fraction increases; however, with the use of the appropriate amount of High Range Water Admixture (HRWA), target slump values can be achieved. Moreover, a considerable improvement in the compressive, tensile, flexural, average residual strength and durability properties was achieved in case of using basalt fibers. On the other hand, corrosion rates increased with the increase in fiber volumes. However, it can be concluded that utilizing a 0.30% fibers volume fraction is the optimum ratio with an overall acceptable performance with respect to mechanical and corrosion properties.

Cracks in single-layer and multi-layer concrete beams

In the study of cracking of concrete beams, cracks are formed and devel-oped depending on many different parameters: size of beam cross section, reinforced concrete material, effective load, calculation method, testing methods, etc. however, single-layer and multi-layer concrete beams, there are additional parameters that affect the formation and development of cracks with the participation of steel fibers in concrete and changes in content of steel fibers in concrete. With normal concrete beams that need to be repaired due to damage during use, the steel fiber concrete layer is poured over or be-low the normal concrete layer, forming laminated beam structure. Multi-layer beam structure has been studied in various forms of static and dynamic problems. However, in this study, the authors considered the formation and development of cracks, the load began to be cracked, the load began to be damaged and the order of the cracks appearing in single-layer and multi-layer steel fiber concrete beams both in testing method and ANSYS numeri-cal simulation method, in which, considering the nonlinearity of materials with a size of 0.15×0.2×2.2m single layer beam and a size of 0.15×0.3×2.2m double layers beam, in the case of steel fiber concrete layer is below the normal concrete layer.

Behavior of Steel‐Fiber‐Reinforced Concrete (SFRC) Slab‐on‐Grade under Impact Loading

Structures such as industrial pavements, roads, parking areas, and airport runways are often slab‐on‐grade where steel‐fiber reinforcement can substitute conventional steel reinforcement. Due to the dynamic nature of loading while in service, these structures are exposed to the damaging effects of impact loading, such as strength and stiffness deterioration in materials or structural elements. In this study, the behavior of concrete slab‐on‐grade with steel‐fiber‐reinforced concrete under impact load has been investigated by considering different parameters. Nonlinear finite element software ABAQUS/Explicit is used to simulate the system. The accuracy of the nonlinear finite element models is verified using experimental work available in the literature. A total of 108 specimens are simulated by varying the volume fraction of steel fiber by 0.5%, 1%, and 1.5% coupling with the impact mass and velocity from the control specimen and variation of load location, thickness, and aspect ratio. The analysis results revealed that the addition of 0.5%, 1%, and 1.5% volume fraction of steel fiber in concrete could effectively accommodate up to 0%, 10%, and 26% reduction of thickness, respectively. These results confirmed that the appropriate use of steel fiber in concrete can be a feasible solution to improve the overall performance of slab‐on‐grade. Moreover, an increase in the aspect ratio of steel fiber improves the crack resistance of steel‐fiber‐reinforced concrete slab‐on‐grade, but a further increase in aspect ratio reduces the performance due to local crushing of concrete.