Slurry Infiltrated Fiber Concrete Research Articles

Performance of Fire Damaged Beam-Column Joints Strengthened with Slurry Infiltrated Fiber Concrete

Performance of Fire Damaged Beam-Column Joints Strengthened with Slurry Infiltrated Fiber Concrete

Post-Fire Behavior of Modified SIFCON One-Way Plates with Waste Tire Rubber under Flexural Load: Experimental and Numerical Study

In this research, an experimental and numerical investigation was conducted to study the flexural behavior of modified slurry-infiltrated fiber concrete slurry-infiltrated fibrous concrete (SIFCON) one-way plates after being subjected to a high temperature. The first part is an experimental work to ensure that the model developed is adequate, while the second part is a 3D finite element modeling of the SIFCON plates with the program ABAQUS using a sequentially coupled thermal displacement analysis. The experimental program included testing eight modified SIFCON plates containing waste powder rubber as a partial substitute for natural sand (0%, 5%, 10%, and 15%). All adopted specimens had identical dimensions (1,000 mm length, 300 mm width, and 50 mm thickness). Four specimens were exposed to fire for 2 hr at a constant temperature of 600°C, after which they were rapidly cooled by spraying them with water. Test results showed that increasing the powder rubber content of burned and unburned modified SIFCON specimens decreased the failure load and increased the specimens’ ductility factor, as well as the ultimate and service deflections. During the test, the failure of SIFCON was observed to be gradual, and the plates remained in contact even after the ultimate load was attained, whereas the failure of the reference mix (without wasted rubber) was observed to be more rapid than that of other SIFCON mixtures. For the flexural test, it gives desirable strength and good fire resistance. This study provides guidance for the study of SIFCON with waste rubber. Overall, the percentage of error between the experimental and numerical results for the load capacity and midspan displacement was about 5.05% and 8.65%, respectively.

Behavior of Fire-damaged RC Beams After Strengthening with Various Techniques

High temperatures during a fire can significantly degrade the structural capacity of concrete. However, in many cases, it is possible to restore and strengthen fire-damaged concrete rather than completely rebuild damaged structures. The study considered two types of concrete (normal 25 MPa and high-strength 65 MPa) with two types of strengthening techniques: carbon-fiber-reinforced polymers (CFRP) sheets with different thicknesses of 1.5 and 2.5 mm and slurry-infiltrated fibrous concrete (SIFCON) jacketing with different fiber sizes of 20 and 30 mm. The numerical simulations and analyses were conducted to capture the complex behavior of fire-damaged concrete members (beams). A fire-damaged concrete beam subjected to an extreme or critical fire Exposure time (2 hours) was evaluated and modified using a finite element simulation approach. The simulation process included three stages: the first, subjecting the concrete beam to thermal loading; the second, reflecting the fire distribution map to another model of applying mechanical loading; and the third, involving the application of strengthening to the damaged model. The results showed that the strengthening using CFRP with a thickness of 2.5 improved the load-carrying capacity compared with SIFCON in both types of concrete. 200% improvement for the normal-strength concrete beam and a 136% improvement for the high-strength concrete beam, compared to the damaged beams. Doi: 10.28991/CEJ-2024-010-01-012 Full Text: PDF

Enhancement of flexural behavior of hybrid flat slab by using SIFCON

Abstract Flat slab systems are widely utilized in construction due to their versatility and efficient use of space. Nevertheless, they are susceptible to flexural failure, particularly in the tension zone. To address this issue, slurry-infiltrated fiber concrete (SIFCON) has been proposed as a solution owing to its exceptional strength and durability. This research examines the effect of utilizing SIFCON in the tension zone of flat slab systems to enhance their flexural performance. The study encompasses testing eight identical slabs, two of which were cast with normal concrete, while the remaining six were hybrid slabs incorporating SIFCON. The specimens were subjected to vertical loading to compare their flexural behavior and identify the optimal dimensions for the SIFCON layer. The slabs had identical dimensions but varied in reinforcement. Group A had a reinforcement ratio of ρ = 0.5%, whereas Group B had a ratio of ρ = 0.335%. All slabs had a constant thickness of the SIFCON layer of 20 mm in the tension zone but varied in the dimensions of the SIFCON layer (100, 50, 30%) from the slab dimensions. A square plate with dimensions (140 × 140 × 20) mm supported the load for all slabs. The load was applied gradually until failure, and the load–deflection curves were recorded for each slab. The result showed that using SIFCON in the tension zone improved the flexural resistance of flat slab systems. The hybrid slabs with SIFCON demonstrated higher ultimate loads and lower deflections than the control slabs that used regular concrete. In particular, the hybrid slabs with a 100% SIFCON layer exhibited the best results, with a rise in ultimate load of 179 and 100% for Groups A and B, respectively, compared to the control slabs. In addition, there was a significant decrease in deflection of 62.35 and 52.38% for Groups A and B, respectively, relative to the control slabs. The study found that the optimal combination of the SIFCON dimension was when the 50% slab dimension was covered and the reinforcing bar area for the hybrid reinforcement system was smaller.

Effect of internal curing on shrinkage and cracking potential under autogenous and drying conditions

Autogenous shrinkage is a significant issue in ultra-high-performance concrete (UHPC). Internal curing has been effective in mitigating autogenous shrinkage, but its impact on drying shrinkage and crack-free concrete needs to be considered. This study investigates the controversial phenomenon of the effect of internal curing on shrinkage strains under drying conditions. A very specific steel fiber reinforced cementitious composite (Slurry infiltrated fiber concrete (SIFCON)) was examined to better understand the cumulative effects. Two additional internal curing water contents (36 kg/m3 and 60 kg/m3) and two superabsorbent polymers (SAP) with different particle sizes (D50: 215 µm and D50: 725 µm) were utilized. Shrinkage measurements were conducted on the SIFCON matrix for early (up to 7 days) and long-term (up to 90 days), under both autogenous and drying conditions. The SIFCON specimens were cured under autogenous and drying conditions for 90 days, then dried to simulate the field conditions, which was followed by crack mapping. The results indicate that SAP effectively mitigates shrinkage strains under both autogenous and drying conditions, attributed to its ability to reduce plastic shrinkage strains during the initial hours. However, crack mapping studies revealed increased cracked areas in specimens with SAP usage, higher internal curing water content, and larger SAP size. Additionally, specimens cured under autogenous conditions exhibited more cracks compared to those cured under drying conditions. This suggests that although shrinkage measurements demonstrate positive effects of internal curing in both conditions, the cumulative effect can vary.

Sustainable one-part alkali activated slag/fly ash Geo-SIFCOM containing recycled sands: Mechanical, flexural, durability and microstructural properties

Slurry Infiltrated Fiber Concrete or Composite (SIFCOM) is a unique form of steel-fiber-reinforced cement composite that possesses exceptional toughness and superior mechanical properties like compressive, shear, tensile, and flexural strengths. New supplies of fine aggregate are required since the construction industry is experiencing natural sand shortage. By thoroughly evaluating workability, mechanical properties, flexural toughness, durability and microstructure, this study demonstrates the potential of various recycled sands from different sources in the manufacture of sustainable slag/fly ash one-part alkali activated SIFCOM (Geo-SIFCOM). Recycled concrete, brick and ceramic sands were used as a substitute of 10, 25 and 50% by volume of silica sand. Steel fiber ratios of 5%, 10%, and 15% were used and exposed to heat curing for 6, 24 and 48 h at 80 °C. Taguchi method was used to investigate the optimum mixture. The results showed that 24 h heat-cured mixture containing 25% recycled concrete sand and 15% fiber (C25F15) had the largest compressive strengths of 68.49 MPa, 74.53 MPa and 80 MPa at 7, 28, and 91 days, respectively. All 6 h – cured mixtures containing 100% slag exhibited the best resistance to freeze-thaw and the mixtures heat cured for 6 h demonstrated the best compressive strength resistance to elevated temperature and F-T cycles regardless of FA content. The largest flexural toughness was also assessed for the mixture with 50% brick sand and 15% fiber (B50F15) heat-cured for 6 h. The mixture with 50% FA and 50%slag (50% ceramic sand and 15% fiber) exhibited the best high temperature resistance.

Literature Review of Cement Matrices and Fibers Used in SIFCON

Conventional concrete is categorized as brittle. As a result, researchers continued working to develop it into a substance having ductile characteristics. Concrete showed remarkable improvement when fiber was incorporated at a ratio of 1-2%. Slurry-infiltrated fiber concrete (SIFCON) allows for the use of up to 20% more fiber when combined with unique cement slurry. Concrete that was produced had increased strength and ductility. The influence of slurry and fiber forms with different volumes on the resistance of concrete to compression, flexural, shear, and bond was the main focus of this review study. The outcomes of several previousinvestigations revealed a significant relationship between the strength of concrete and the slurry mixture, fiber type, and fiber volume. Additionally, it was shown that the majority of research all agreed that certain methods should be followed when employing a volume of more than 5% fiber. These processes entail employing fine-sand less than 1 mm in size to create a suitable cementslurry and replacing up to30% of the cement with fly ash (FA), silica fume (SF), and metakaolin to create a cement slurry capable of penetrating interlocking with fiber of all forms and volumes

The flexural and shear behavior of SIFCON concrete beams with steel and GFRP bars

The SIFCON concrete reinforced with glass-fiber reinforced polymer (GFRP) bars can provide a construction system with high durability and strength. Slurry infiltrated fibrous concrete (SIFCON) is a new type of conventional fiber reinforced concrete. The aim of this paper is to evaluate the flexural and shear behavior of the SIFCON concrete beams reinforced with GFRP bars were evaluated under four-point bending and three-point shear tests. The parameters investigated were material type of longitudinal reinforcement (steel and GFRP), transverse reinforcement type (steel and mesh) and mesh reinforcement spacing (25 mm and 12 mm). For this purpose, a total of twelve SIFCON concrete beams with steel and GFRP bar as longitudinal reinforcement measuring 150x150x800 mm were cast. Moreover, stirrup and mesh reinforcement as transverse reinforcement are another main parameter of this study. The test results showed that the effects of longitudinal and transverse reinforcement type and mesh spacing on the strength, crack propagation, and energy dissipation capacity of RC beams under bending and shear were experimentally investigated. The use of steel longitudinal reinforcement in both four-point and three-point tests increased the bending moment and shear strength compared to beams with GFRP. Moreover, although the use of mesh reinforcement in reinforced concrete beams under four-point bending reduced the strength, it increased the strength in beams with GFRP. In the samples under the shear force, the use of mesh reinforcement in the steel reinforced group increases the shear strength, but the use of mesh reinforcement in the GFRP group decreases the shear strength.

Slurry infiltrated fiber concrete (SIFCON) for use in ballistic and fire protection of military structures

The materials used for the architectural shielding of civil structures must protect against impacts, explosions, and fire. However, Portland cement-based concrete (OPC) degrades when exposed to high temperatures. These requirements and the limitations of OPC promotes research on alternative concretes for ballistic and fire protection uses. Therefore, this research analyzes the potential application of slurry infiltrated fiber concrete (SIFCON) in constructing structures resistant to both fire and ballistic impacts. The SIFCON is based on the alkaline activation of ceramic waste (Ce) with the incorporation of short steel fibers (38 mm). Ballistic tests were conducted using 9 mm caliber ammunition with two types of weapons: the CZ 10P pistol (5 impacts) and the Beretta CX4 submachine gun (1 burst of 3 impacts). The results indicate that SIFCON-Ce exhibits greater thermal stability and fire resistance compared to SIFCON-OPC. Specifically, the residual flexural strength at 900 °C was 75.1 % for SIFCON-Ce and 46.1 % for SIFCON-OPC. Additionally, the inclusion of steel fibers enhanced the material's ability to resist impacts (9 mm caliber) generated by the CZ 10P pistol and Beretta CX4 submachine gun, leading to the classification of SIFCON as a suitable material for architectural armor, with protection levels of type II-A and III-A according to the NIJ 0108.01 standard.

Mechanical properties of slurry-infiltrated fiber concrete (SIFCON) as sustainable material with variable fiber content

For any member, sustainability is very important, which refers to the capacity to endure. Normal concrete has low tensile strength and could not exhibit significant tensile strain margins. Accordingly, it is essential to implement strategies that can enhance the behavior of conventional concrete before using it as structural concrete. Therefore, using Slurry-Infiltrated Fiber Concrete (SIFCON) composites is a current innovation in the field of civil engineering that has a considerable influence. This study presented an experimental study to improve the mechanical efficiency of a SIFCON mix with varying fiber content. To satisfy this objective, several SIFCON mixes, incorporating hook-end steel fiber with three different volume fractions (6, 7, and 8.5%) were prepared. The prepared mixtures performed compressive strength tests at 7 and 28 days, splitting tensile strength tests, and flexural strength tests both in the fresh and hardened states. The results pointed out that the fresh state mortar had proper filling and flow ability properties, satisfying the spread diameter requirement (between 240 and 260 mm) for SIFCON mortar, which is equal to 249 mm. For mechanical performance, the maximum compressive strength increased by 53% after 28 days for the mix’s SF of 8.5%. Furthermore, when compared to the reference mix, splitting, and flexural enhancement increased by 44% and 91%, respectively. On the other hand, the failure shape of SIFCON for all tested mixes has an impact on strengthening, that’s assigned to the high vast area of SF.

Experimental study on flexural behavior of reinforced lightweight concrete beams strengthening with a slurry infiltrated fiber concrete (SIFCON)

Experimental study on flexural behavior of reinforced lightweight concrete beams strengthening with a slurry infiltrated fiber concrete (SIFCON)

Post Fire Behavior of Structural Reinforced Concrete Member (Slab) Repairing with Various Materials

One of the most significant building materials used to build a variety of infrastructure, military, and civil structures is concrete. It can effectively withstand fire mishaps for a long period of time. This study employs a finite element simulation approach in Three steps: the first involves applying mechanical loading, the second involves applying mechanical and thermal loading; and the third involves strengthening the damaged model. Two different strengthening procedures were used to evaluate the performance of the fire-damaged slab. Two types of strengthening techniques—carbon-fiber-reinforced polymer (CFRP) sheet and slurry-infiltrated fibrous concrete (SIFCON) jacketing—were used. Studying the performance of SIFCON and CFRP together and in two different thicknesses of each for repairing both normal and high-strength concretes after fire exposure is considered limited. An investigation of their behavior can provide insights into how effective the restoration of strength is. The study aims to assess how well various repair materials perform in restoring the durability and strength of reinforced concrete members after being exposed to fire. This will assist in determining the best materials for concrete repair after a fire. Results show that the enhancements by SIFCON with a thickness of 30 mm significantly improved many indices, including load displacement behavior, ductility, and absorption energy of the slab. Doi: 10.28991/CEJ-2023-09-08-013 Full Text: PDF

Mechanical Characteristics of Slurry Infiltrated Fiber Concrete

This paper presents and evaluates a new method for producing Slurry Infiltrated Fiber Concrete (SIFCON). A study was carried out to investigate the impact on the mechanical properties of SIFCON, where several cubes, cylinders, and prisms were cast to compare the proposed gradual and the traditional multi-layer method using the same mixing proportions: 6% straight steel fiber, cement, sand, 10% silica fume replacement, and 2.4% superplasticizer. The results showed that when using the proposed gradual mix method, compressive strength, splitting tensile strength, modulus of elasticity, and modulus of rupture improved by 15.21%, 8.06%, 9.07%, and 5.26% compared to the traditional multi-layer method.

Flow Characteristics of Slurry Infiltrated Fibrous Concrete (SIFCON) with Silica Fume and Steel Fibers

SIFCON is one of the newly established buildings substantial. The proportion of silica fume additional was 17.5% through mass of cement in slurry infiltrated fibrous concrete & four various bulk segments of plain mild steel fibres, crimped mild steel fibres and hooked ended mild steel fibers (0, 5, 15, 25 and 35) % were utilized. The examined belongings of fresh slurry infiltrated fibrous concrete were normal slump cone test, reversed slump cone test, mini slump cone trial, J- fibres penetration test and L-box test test which were agreed out on usual magnitude of slump cones, J-box and L-box respectively at fresh state of SIFCON slurry (mortar). The spread flow diameter for standard slump cone, inverted slump cone and mini slump cone values up to 670mm, 650mm and 175mm respectively were obtained at fresh state of SIFCON slurry (mortar).

Development of an Engineered Slurry-Infiltrated Fibrous Concrete: Experimental and Modelling Approaches

Concrete is the central pile for the infrastructure that maintains civilisation and human life. The concrete industry faces many challenges, including improving mechanical properties, eco-friendliness, and durability. In this context, the present study focuses on evaluating and modelling themechanical properties of engineered concrete, namely slurry-infiltrated fibrous concrete (SIFCON). The main experiments will be devoted to measuring and modelling the failures of slabs made from SIFCON under two loading systems, namely static and impact loading systems. The model was developed using a non-linear finite element analysis. The experiments considered the influence of the geometry of the reinforcement steel fibres (hook-end fibres, microfibres, and combined hook-end and microfibres), sizes of fibres, and slab dimensions. The outcomes of this investigation showed that increasing the slab’s thickness enhances the load-bearing capacity of the SIFCON slab, and the microfibres and combined hook-end and microfibres improved the load-bearing capacity of the slab compared to the hook-end fibre. Generally, it was noticed that the outcomes of the experiments agreed with the modelling outcomes. Nevertheless, it was noticed that experimentally measured axial deformation was more significant than the predicted axial deformation. In summary, the difference between experimental and modelling outcomes was 1.1–10.2%, with a standard deviation of 0.0264. Based on the excellent ability of SIFCON to resist impacts and dynamic loads, it is recommended to be used in pavements, military structures, nuclear reactor walls, and in areas subjected to high bending moments, such as corner connections subjected to opening bending moments.

Impact and Blast Resistance of Slurry Infiltrated Fiber Concrete (SIFCON): A Comprehensive Review

The construction field developed Slurry Infiltrated Fiber Concrete (SIFCON) to improve mechanical properties considerably. The durability and ductility of this unique kind of concrete have significantly improved as well, and it has a higher energy absorption capacity. SIFCON differs from other fiber-reinforced concretes because it is produced in a different process, and finally, it contains a significant quantity of fiber, up to 20% or even more. In recent years, several research studies have been conducted on SIFCON, mainly focusing on the performance under impact and blast loading. Although this type of concrete is currently being utilized for significant structures, such as energy plants and military buildings, little is known about how it will respond to blast loads. The aim of this study is to analyze the research findings on enhancing the characteristics and toughness of SIFCON during impact and explosion situations. The review provides essential details about SIFCON that specialists in this field would need to know.

Effect of steel fiber in SIFCON using GGBS as binder replacement

The materials used in the high-performance concrete leads to extreme brittleness, to overcome these different fibres are introduced in the concrete to improve its tensile strength and ductility. Slurry Infiltrated Fibrous Concrete (SIFCON) is one type of special concrete in which steel fibres are placed in an effective way for its interlocking system for concrete toughness. In this study SIFCON with two different steel fibres hooked end and crimped end were used in different volume ratios of 5%, 6%, 7%, 8% and 9% separately to investigate its mechanical properties. The further investigation was carried out by replacing Ground Granulated Blast Slag (GGBS) as binder replacement with optimum fibre ratio. From the results it is concluded that hooked end fibre shows an increasing performance when compared to crimped end fibre. Similarly, the strength increment is observed when GGBS is used as binder replacement at 40%. Microstructural analysis with the help of SEM and XRD are performed, and the results indicated that a similar hydration phase with increased rate is observed in SIFCON when compared to conventional concrete.

Experimental Study on the Behavior of Axially Loaded Reinforced Concrete Square Columns Strengthened with SIFCON Shell

Slurry infiltrated fiber concrete (SIFCON) is an advanced generation of fiber-reinforced concrete (FRC) with higher fiber content. SIFCON offers excellent potential for use in areas that require high ductility and impact resistance, particularly when designing seismic retrofits and repairing or strengthening structural reinforced concrete members. This study investigated the behavior of square normal strength concrete (NSC) columns of grade M35 strengthened with SIFCON shell and compared them with unstrengthen NSC. The effect of different SIFCON shell thicknesses (2 and 3) cm, fiber type and volume fraction (4 and 6%), and tie spacing (8 and 16) cm were studied. The fiber types employed were polypropylene and hooked-end steel fiber. Eleven columns were cast and tested for the current investigation in two groups, where the first group (control specimens) consists of two unstrengthen NSC columns and one square NSC column strengthened with a 2 cm SIFCON shell with a 6% steel fiber ratio. The second group comprises eight NSC columns strengthened with a hybrid fiber SIFCON shell. The NSC square columns had dimensions of (8x8x80) cm. 3 cm SIFCON shell thickness was observed to evolve the strengthen columns' load-carrying capacity and energy absorption. The maximum load achieved is about 223% as compared with unstrengthened NSC columns. The energy absorption was about 16 times that of the control. At the same time, the stiffness of strengthened columns is less than that of NSC columns.

Empirical Relationship between the Impact Energy and Compressive Strength for Slurry Infiltrated Fibrous Concrete (SIFCON)

In this research, an empirical relationship between the impact of energy and compressive strength is developed using regression analysis. For this, simple, practical, and economical drop weight test was performed on Slurry Infiltrated Fibrous Concrete which was based on the testing procedure recommended by ACI committee 544. Hook ended steel fibre of 35 mm length and an aspect ratio of 60 was used as the reinforcing material in four different volume fractions such as 0%, 2%, 3% and 4% with water cement ratio of 0.4. The test results indicated that increasing volume fraction of fibre increased the impact resistance of concrete specimen. It is also found that the empirical relationship obtained from the regression analysis is accurate and preferable to evaluate the impact energy by using compressive strength of Slurry Infiltrated Fibrous Concrete thus eliminating the drop weight test.

Effects of fibers geometry and strength on the mechanical behavior and permeability properties of slurry infiltrated fiber concrete (SIFCON)

The use of slurry-infiltrated fiber concrete (SIFCON) has been increasing in recent years. SIFCON is a very good alternative, especially in structural reinforcement processes. In this study, the effects of 2 different steel fibers of normal strength (3D) and high strength (5D) with different geometry and strength properties and polyolefin origin synthetic fiber are examined on the mechanical behavior and capillary water permeability properties of SIFCON. Steel fibers were used in 2 different ratios by volume 4% and 8%, while polyolefin synthetic fiber was used at 4% by volume. The bending strength and splitting tensile strength of SIFCON containing 5D steel fiber are 46.47 MPa and 18.47 MPa, respectively, 4.9 and 2.1 times higher than plain concrete. In addition, the fracture energy of SIFCON containing 5D steel fiber is 20400 N/m, and it is 358 times higher than plain concrete, 1.6 and 3.1 times higher than concrete containing the same amount of 3D fiber and polyolefin synthetic fiber, respectively. The capillary water absorption of SIFCON, which contains 4% synthetic fiber and 8% 3D steel fiber by volume, is 0.121 mm and 0.112 mm, respectively, which is higher than all other mixtures in the study. As a result of the study, higher splitting tensile strength, bending strength and fracture energy values were obtained in concretes containing 5D steel fiber, which have high tensile strength and have better adhesion to concrete due to its geometry. The use of synthetic fibers or high amounts of steel fibers increased the permeability.