Slurry Infiltrated Fiber Research Articles

Compressive Bearing Capacity and Ductility of Slurry-Infiltrated Fiber Concrete Blocks with Two-Dimensional Distributed Steel Fibers

Slurry-infiltrated fiber concrete (SIFCON) has excellent potential for application as a new material with good crack resistance, impact resistance, and seismic performance. In this paper, SIFCON blocks were cast in a single pour using the custom-made two-dimensional directional steel fiber placement device, followed by compressive testing. Based on the test results, the effects of fly ash substitution rate, steel fiber aspect ratio, and steel fiber volume fraction on the compressive bearing capacity and ductility of SIFCON blocks were investigated. The results indicate that the custom-made device in this paper effectively achieves the directional placement of steel fibers, offering a cost-effective solution that optimizes the construction process. Regarding the test results, it was observed that the compressive bearing capacity of SIFCON blocks decreases linearly with increasing fly ash substitution rate, while the addition of fly ash improves the ductility of the blocks. Notably, a 31% decrease in bearing capacity was noted when the fly ash substitution rate increases from 0% to 40%, whereas the ductility ratio increased by 99% for the same substitution rate range. Furthermore, the results revealed a positive correlation between the bearing capacity and ductility of SIFCON blocks with higher steel fiber aspect ratios and volume fractions. Specifically, the bearing capacity increased by 19% and 33% with steel fiber aspect ratio increments from 33 to 70 and volume fraction increases from 10% to 14%, respectively. Additionally, the ductility ratio of the test blocks increased by 104% when the aspect ratio of the steel fibers increased from 33 to 70, and by 37% when the volume fraction of steel fibers rose from 10% to 14%.

Experimental Behavior of SIFCON Corbels

This study explores the performance of six Slurry Infiltrated Fiber Concrete (SIFCON) corbels with a constant steel fiber volume of 6%, under varying vertical loads. By altering the shear span-to-depth ratio (a/d) from 0.4 to 0.6 and utilizing different fiber types (hooked end and micro) and reinforcement configurations (2Ø12mm and 3Ø12mm), the research examines the impact on maximum and cracking load capacities of the corbels. Results indicate that the a/d ratio, along with fiber type and reinforcement choice, significantly influences the structural behavior, offering insights for enhancing SFRC corbels' design and efficiency in construction applications. Highlights: Shear Span Impact: Changing the shear span-to-depth ratio critically affects load capacity. Material Influence: Fiber types and reinforcement configurations alter load behavior. Design Implications: Results highlight the importance of design choices in enhancing SIFCON corbels' structural performance. Keywords: SIFCON, Corbels, Shear Span, Steel Fiber, Load Capacity

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.

Evaluation of the performance of slurry infiltrated fibre concrete slabs exposed to hydrocarbon fire

Evaluation of the performance of slurry infiltrated fibre concrete slabs exposed to hydrocarbon fire

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.

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

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)

Compressive properties of a novel slurry-infiltrated fiber concrete reinforced with arc-shaped steel fibers

Compressive properties of a novel slurry-infiltrated fiber concrete reinforced with arc-shaped steel fibers

Effect of absorption determining methods of superabsorbent polymers in cementitious environments on the fresh properties

Autogenous shrinkage can be mitigated by the use of superabsorbent polymers (SAP) as internal curing agents. SAP are a competitive alternative to lightweight aggregates since SAP could absorb water 20–30 times by its mass in cementitious environments. There is no general agreement on determining the absorption capacity of SAP in cementitious environments. In this study, the absorbency of SAP was determined with the teabag, flow table, and point-count (ASTM C 457) methods. Two SAP with different particle sizes (D50: 215 µm and D50: 725 µm) were used in the mixtures to examine the effect of particle size on fresh properties. Also, two concrete types (slurry infiltrated fiber concrete’s matrix and ordinary mortar) to examine the usability of the methods in different rheological characteristic concretes. This study aimed to use optimal additional water without compromising workability and w/c ratio. Absorption capacities were found to be lower for the point-count method since the flow table method are not taking into account the filler effect of SAP in the mixtures. Using the absorption values obtained from the point-count method, affected slurry infiltrated fiber concrete’s fresh properties negatively. On the other hand, it has been found that this effect was limited for ordinary mortars. Results indicated that even though the point-count method could be more accurate, concrete type is also important when choosing a method to determine the absorption capacity of SAP.

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.

Pure and mixed-mode (I/III) fracture toughness of preplaced aggregate fibrous concrete and slurry infiltrated fibre concrete and hybrid combination comprising nano carbon tubes

Concrete is the most widely used and inexpensive material in the construction sector. However, due to its weakness in tension, the cracking and brittle fracturing of concrete is considered a major deficiency. Advancements in fibrous concretes have recently been emerged to mitigate this issue. Preplaced Aggregate Fibrous Concrete (PAFC) and Slurry Infiltrated Fibrous Concrete (SIFCON) are unique cement composites made of fibres with surpassing mechanical properties and exceptional toughness values. The production of PAFC and SIFCON involves packing of aggregates and fibres in the mould and filling the gaps between the aggregates with the high flowability injected cement grout. Nevertheless, the mono and hybrid layered effect of PAFC and SIFCON on fracture toughness is still unexplored and needs special attention to bridge this research gap. This research examined the pure (I and III) and mixed (I/III) modes of fracture toughness of PAFC, SIFCON and hybrid two-layered PAFC-SIFCON samples. For this purpose, many notched specimens of circular disc shapes were prepared using single and double-layer concepts. To investigate the effect of fibres, three different fibre types were used; hooked-end steel fibre, macro polypropylene fibre and hybrid shape of crimped-hooked end steel fibre with dosages of 2.4% and 8% by volume to produce PAFC and SIFCON, respectively. Additionally, multi-walled nano-carbon tubes (MWCNT) were added to the composites with a dosage of 0.1% by cement weight. The compressive strength, stress intensity factors, effective stress intensity factors, mixity parameter, failure pattern, range of fracture toughness and scanning electron microscope were examined, discussed, and compared. Results indicated that pure mode III has a greater cracking risk than both mode I and mixed-mode I/III. The mixed-mode fracture toughness of PAFC specimens improved by 33.07 to 67.94%. Similarly, this improvement ranged from 59.77 to 210.70% for SIFCON and from 51.0 to 131.55% for PAFC-SIFCON. In addition, the fracture toughness of SIFCON is considerably higher than the PAFC and hybrid combination. In all three composite types, the hybrid shape steel fibre outperformed the hooked-end steel and polypropylene fibre under all three modes.

Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams

This paper aimed to investigate the effect of using ductile materials in the compression zone on the flexural performance of over-reinforced concrete beams. In order to avoid brittle compression failure, partial replacement of concrete with ductile materials layer in the compression zone was used. Four over-reinforced concrete beams of size 120 × 180 × 1,300 mm were cast and tested under three-point loading conditions. The steel fibers reinforced concrete (SFRC), slurry infiltrated fiber concrete (SIFCON), and ultra-high performance fiber reinforced concrete (UHPFRC) were used as ductile materials. The flexural capacity of the beams, failure modes, crack patterns, load-deflection relationships, ductility index, and toughness were investigated. The results showed that using ductile materials in the compression zone is an effective technique to increase the ultimate load, ductility, and toughness by up to 52.46, 84.78 and 279.93%, respectively, compared to the reference beam. In addition, the failure mode changed from brittle to ductile failure. Noting that the use of SFRC layer enhanced the ductility of over-reinforced concrete beams more than using UHPFRC and SIFCON layers. Also, one of the main advantages of this technique is led to increase the tensile reinforcement ratio up to 8.548% without needing the compressive reinforcement. Thus, ductile composite beams with a high flexural capacity were generated using an economical amount of ductile materials.

Non-Linear Static Analysis of Hollow and Solid SIFCON column under Axial Loading

Abstract: Concrete is a crucial material for creating various structures. The use of steel fiber reinforcement in concrete improves the ability of structural elements to withstand high stresses. SIFCON (Slurry Infiltrated Fiber Concrete) is a relatively new composite material using steel fibers in a cement-based matrix.SIFCON column is an innovation in the field of civil engineering that enhances the constructability.This paper aims to the Non-linear static analysis of hollow and solid SIFCON hexagonal columns under axial loading. For this study, three finite element models of Hexagonal SIFCON column with Hooked end steel fibers were analyzed using Ansys 2016 R1. Different hollow ratios is evaluated under axial loading to understand the total deformation and equivalent stress.The Study shows that hexagonal solid column shows maximum load carrying capacity than hexagonal hollow columns.

Experimental investigation of fire effects under axial compression on ductility and stiffness of (SIFCON) columns

AbstractThis article is an experimental study of the efficiency after fire exposure of slurry infiltrated fiber concrete (SIFCON) columns. The aim of this paper is to present a comprehensive study of the fire effect on the stiffness, ductility, and energy absorption capacity of axially loaded SIFCON columns and to inspect the effect of hollow ratio and cross section shape on the energy dissipation ability, ductility, and stiffness features of the post‐fire behavior of these columns. Hybrid fibers were used to cast SIFCON columns with 6% fiber ratio (3% hooked end fiber + 3% straight micro fiber). The results showed that the cube compressive strength decreased by 25.1% and 53% when exposed to fire at a temperatures of 600 and 900°C, respectively. The results obtained revealed that after exposure to fire, the indices values of displacement ductility are not strongly impaired and it has been shown that the assessment of the energy dissipation ability is more relevant in this situation. Whereafter fire exposure at 600°C, the SIFCON columns lost about 11%–31% of the energy absorption capacity and about 39%–57% after fire exposure at 900°C. In comparison, after fire exposure, the secant and initial stiffness greatly degraded and the reduction percentages became higher with a rise in fire temperature from 600 to 900°C.

Experimental investigations and nonlocal computational models of slurry infiltrated fiber concrete with CaCO3 whiskers

Experimental investigations and nonlocal computational models of slurry infiltrated fiber concrete with CaCO3 whiskers

Effect of Distributing Steel Fibers on Some Properties of Slurry Infiltrated Fiber Concrete

The slurry infiltrated fiber concrete (SIFCON) is nowadays considered a special type of high fiber content concrete; it is high strength and high performance material. This paper investigates the effect of spread steel fiber into the slurry mortar on some properties of SIFCON. According to fiber distribution, two sets were used in this investigation. The first set consisted of randomly distributing fibers inside the slurry. The second set was by placing the fibers in an orderly manner inside the slurry. Crimped steel fibers with an aspect ratio of (60) were used. Two different volume fractions percentage of (7% and 9%) by volume of mold were used in both sets for this study. Also, a w/c ratio of (0.35) and superplasticizer of (1%) by weight of cement was used to ensure the penetration of the slurry inside the fibers. The compressive and flexural strength were conducted on standard cubes (10*10*10) cm and prisms of (40*7*7) cm respectively to find the effect of how the steel fibers were distributed. The results showed that distributing the fibers randomly gave better results than the ordered distribution. The increment percentage in compressive strength and flexural strength were (1.5%, 6.9%, 23%, and 6.5%), respectively, for both sets and both fiber volume fractions (7% and 9%).

Shear strengthening of continuous prestressed concrete beams with precast SIFCON laminates subjected to monotonic and repeated loads

Slurry Infiltrated Fibre Concrete (SIFCON) is one of the recently developed construction material that can be considered as a special type of high performance fibre reinforced concrete (HPFRC) with higher fibre content. This study describes the findings of an experimental research to determine the contribution of Precast SIFCON Laminates to the enhancement of the shear strength of continuous prestressed concrete beams. Precast SIFCON Laminates were used in the investigation. It was decided to test six two-span prestressed high strength concrete continuous beams with rectangular cross-sections, each of which had a rectangular cross section. In this case, two beams were left un-enhanced as a control, and the other four beams were strengthened with varied arrangements of Precast SIFCON Laminates. The variables chosen were several wrapping strategies for the Precast SIFCON Laminates, which were then tested. The aim was to develop a better understanding of the shear contribution of Precast SIFCON Laminates and to investigate the effect of repeated loading. The results indicate that the strengthening the maximum shear regions with precast SIFCON laminates glued by epoxy resin led to improve the shear behavior the delay in first crack appearance time reached (26.4%−105.7%), Increased the ultimate shear capacity of the tested beams (19.2%–46.5%), The improvement in stiffness about (94.5%–144.9%) and the Experimental results explained that the ultimate shear strength for beams that are tested under repeated loads is a little reduced (2.2%–3.8%), comparing with the strength of the same beams under monotonic static loading.

Relationship between Density and Early Compressive Strength of Slurry Infiltrated Fiber Reinforced Concrete (SIFCON)

The aim of the study is to study the physical and mechanical characteristics of Slurry Infiltrated Fiber Reinforced Concrete with fiber percentage volume of 5% and lower. For the testing of physical characteristics of the concrete, density test been conducted. For the testing of mechanical characteristics, compression test used to determine strength of concrete sample. The density of Slurry Infiltrated Fiber Reinforced Concrete increased when the usage of steel fiber percentage volume increases from 1% to 5%, nevertheless when compared to density of ordinary concrete, ordinary concrete is denser. For the significant of study, the mechanical properties of Slurry Infiltrated Fiber Reinforced Concrete, compressive strength increased when the fiber content increases from 1% to 5% percentage volume.