scholarly journals Shrinkage and Mechanical Properties of Self-Compacting SFRC With Calcium-Sulfoaluminate Expansive Agent

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 588 ◽  
Author(s):  
Changyong Li ◽  
Pengran Shang ◽  
Fenglan Li ◽  
Meng Feng ◽  
Shunbo Zhao
Keyword(s):  
Mechanical Properties ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Steel Fiber Reinforced Concrete ◽  
Volume Stability ◽  
Calcium Sulfoaluminate ◽  
Expansive Agent

With the premise of ensuring workability on a fresh mixture, the volume stability of hardened self-compacting steel fiber reinforced concrete (SFRC) becomes an issue due to the content of cementitious materials increased with the volume fraction of steel fiber. By using the expansive agent to reduce the shrinkage deformation of self-compacting SFRC, the strength reduction of hardened self-compacting SFRC is another issue. To solve these issues, this paper performed an experimental investigation on the workability, shrinkage, and mechanical properties of self-compacting SFRC compared to the self-compacting concrete (SCC) with or without an expansive agent. The calcium-sulfoaluminate expansive agent with content optimized to be 10% mass of binders and the steel fiber with a varying volume fraction from 0.4% to 1.2% were selected as the main parameters. The mix proportion of self-compacting SFRC with expansive agent was designed by the direct absolute volume method, of which the steel fibers are considered to be the distributed coarse aggregates. Results showed that rational high filling and passing ability of fresh self-compacting SFRC was ensured by increasing the binder to coarse-aggregate ratio and the sand ratio in the mix proportions; the autogenous and drying shrinkages of hardened self-compacting SFRC reduced by 22.2% to 3.2% and by 18.5% to 7.3% compared to those of the SCC without expansive agent at a curing age of 180 d, although the expansion effect of expansive agent decreased with the increasing volume fraction of steel fiber; the mechanical properties, including the compressive strength, the splitting tensile strength, and the modulus of elasticity increased with the incorporation of an expansive agent and steel fibers, which met the design requirements.

Study on Retrofitting and Strengthening of Reinforced Concrete Beams Using Fibrous Concrete

2021 ◽  
Vol 9 (8) ◽  
pp. 1676-1684
Author(s):  
Natalia Sharma
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Cement Matrix ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

Abstract: Reinforced concrete structures are frequently in need of repair and strengthening as a result of numerous environmental causes, ageing, or material damage under intense stress conditions, as well as mistakes made during the construction process. RC structures are repaired using a variety of approaches nowadays. The usage of FRC is one of the retrofitting strategies. Steel fiber reinforced concrete (SFRC) was used in this investigation because it contains randomly dispersed short discrete steel fibers that operate as internal reinforcement to improve the cementitious composite's characteristics (concrete). The main rationale for integrating small discrete fibers into a cement matrix is to reduce the amount of cement used. The principal reason for incorporating short discrete fibers into a cement matrix is to reduce cracking in the elastic range, increase the tensile strength and deformation capacity and increase the toughness of the resultant composite. These properties of SFRC primarily depend upon length and volume of Steel fibers used in the concrete mixture. In India, the steel fiber reinforced concrete (SFRC) has seen limited applications in several structures due to the lack of awareness, design guidelines and construction specifications. Therefore, there is a need to develop information on the role of steel fibers in the concrete mixture. The experimental work reported in this study includes the mechanical properties of concrete at different volume fractions of steel fibers. These mechanical properties include compressive strength, split tensile strength and flexural strength and to study the effect of volume fraction and aspect ratio of steel fibers on these mechanical properties. However, main aim of the study was significance of reinforced concrete beams strengthened with fiber reinforced concrete layer and to investigate how these beams deflect under strain. The objective of the investigation was finding that applying FRC to strengthen beams enhanced structural performance in terms of ultimate load carrying capacity, fracture pattern deflection, and mode of failure or not.

scholarly journals Mechanical Properties and Explosive Spalling Behavior of Steel-Fiber-Reinforced Concrete Exposed to High Temperature—A Review

2020 ◽  
Vol 10 (7) ◽  
pp. 2324 ◽  
Author(s):  
Peng Zhang ◽  
Luoyi Kang ◽  
Juan Wang ◽  
Jinjun Guo ◽  
Shaowei Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Elevated Temperatures ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Explosive Spalling ◽  
Residual Properties

Steel-fiber-reinforced concrete (SFRC) is being increasingly applied to various buildings and civil infrastructure as an advanced cementitious composite. In recent years, the requirements for SFRC in the construction industry have increased. Additionally, the fire resistance of SFRC has attracted attention; therefore, numerous investigations regarding the residual properties of SFRC have been conducted. This paper critically reviews the mechanical properties of SFRC subjected to elevated temperatures, including its residual compressive strength, flexural strength, tensile strength, elastic properties, fracture properties, and stress–strain relationships. The residual mechanical performance of SFRC and the action mechanism of steel fibers are reviewed in detail. Moreover, factors affecting the explosive spalling of concrete at high temperatures as well as the effect of steel fibers on the microstructure of heated concrete are discussed. It is demonstrated that, in general, SFRC exhibits better residual mechanical properties when exposed to elevated temperatures than plain concrete and can prevent the risk of explosive spalling more effectively. The purpose of this literature review is to provide an exhaustive insight into the feasibility of SFRC as a refractory building material; additionally, future research needs are identified.

Influence of Dispersed Reinforcement on the Physico-Mechanical Properties of the SFRC

2017 ◽  
Vol 755 ◽  
pp. 75-81 ◽  
Author(s):  
Tereza Komárková ◽  
Jaromír Láník ◽  
Petr Dvořák
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Steel Fiber ◽  
Fresh Concrete ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Mechanical Parameters ◽  
Steel Fiber Reinforced Concrete ◽  
The Individual ◽  
Building Practice

The article deals with steel fiber reinforced concrete (SFRC), specifically with its physical mechanical parameters which influence both design and reliable behavior of the building material in structures. The resulting physical mechanical properties of the SFRC depend on the properties of the individual components and also on their quantity. In the building practice, a common dosing of steel fibers that are added into fresh concrete mixture is ranging between 0.5% and 2%. The paper also describes the methodology of certain laboratory tests suitable for SFRC and the ways of data evaluation. The experiments proved a substantial influence of the quantity of steel fibers in the individual mixtures to the resulting mechanical properties.

scholarly journals Hysteretic Behavior of Reinforced Concrete Coupling Beams According to Volume Fraction of Steel Fiber

2020 ◽  
Vol 13 (1) ◽  
pp. 182
Author(s):  
Joo-Hong Chung ◽  
Dong-Hee Son ◽  
Su-Yong Kim ◽  
Baek-Il Bae ◽  
Chang-Sik Choi
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforcement ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Hysteretic Behavior ◽  
Steel Fiber Reinforced Concrete ◽  
Coupling Beams ◽  
Cyclic Loading Tests

The purpose of this study was to evaluate the structural performance of steel fiber reinforced concrete (SFRC) coupling beams. Reversed cyclic loading tests were performed with full-scale specimens. The main variable for the tests was the volume fraction ratio of the steel fibers. The results showed that the maximum strength was increased by about 11% with 1% of steel fibers incorporated, and about 24% when the ratio of mixed fibers was doubled to 2%. Because numerous microcracks occurred, decreased crack width due to the bridge effect was observed with the steel fiber reinforcement. Increased diagonal tension crack angles and energy dissipation also appeared as the volume fraction of steel fibers increased. The contribution of shear to the total deformation was decreased while the contribution of rocking was increased as steel fibers were added. Considering the results of these experiments, it can be concluded that steel fiber reinforcement affects the deformation of coupling beams in various ways, and should be considered when estimating the effective stiffness of such beams when SFRC is introduced.

Experimental Study on Effects of Steel Fiber Volume on Mechanical Properties of SFRC

2011 ◽  
Vol 214 ◽  
pp. 144-148 ◽  
Author(s):  
Farnoud Rahimi Mansour ◽  
Sasan Parniani ◽  
Izni Syahrizal Ibrahim
Keyword(s):  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Engineering Properties ◽  
Water Tank ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Modes Of Failure

In recent years, considerable interest has developed in using fibers to increase the load-carrying capacity of concrete members. Fibers significantly reduce the brittleness of concrete and improve its engineering properties, such as tensile, flexural, impact resistance, fatigue, load bearing capacity after cracking and toughness. However, studies on the exact amount of influence are very limited. Among fibers, steel fibers are one of the most popular and widely used types of fibers in both research and practice. Steel fiber-reinforced concrete (SFRC) has been used increasingly in recent years and has a lot of applications. Previous researchers have mentioned that using fiber as 0.5 – 2.5 % of the volume of concrete can significantly improve the concrete properties. The purpose of this paper is firstly to investigate the effects of fiber volume on the compressive, splitting, and flexural behaviors of SFRC, and secondly to compare modes of failure. Variable items are the steel fiber volume fraction and the curing day. A series of 108 specimens (cube, cylinder and prism) with four different steel fiber volumes are used by a ratio of 0, 0.7, 1.0 and 1.5%. All specimens are cured in a water tank for 7, 14 and 28 days, respectively to provide same conditions. Hooked-ended steel fibers with a length of 30mm and a diameter of 0.75 mm are used.

scholarly journals Effects of Steel Fibers Geometry on the Mechanical Properties of SIFCON Concrete

2020 ◽  
Vol 6 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Shahad S. Khamees ◽  
Mohammed M. Kadhum ◽  
Nameer A. Alwash
Keyword(s):  
Mechanical Properties ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Partial Replacement ◽  
Fiber Volume ◽  
Fiber Network ◽  
Static Modulus ◽  
Static Modulus Of Elasticity

This research aims to shed light on the effect of steel fiber shape, length, diameter, and aspect ratio on the mechanical properties of slurry infiltration fiber reinforced concrete (SIFCON). This study comprised of casting and testing three groups of SIFCON specimens with 6% fiber volume fraction. The first group was reinforced with micro steel fiber, other reinforced by hook end steel fibers, while the last group of specimens reinforced by mixing two shape of steel fiber as hybrid fiber (3% micro steel fiber +3% hook end steel fiber). Silica fume was used as a partial replacement (10%) by weight of cement. 3.7% super plasticizer was used to make the slurry liquid enough to penetrate through the fiber network, while the w/c ratio kept constant at 0.33. It was found from the results achieved that the compressive strength, static modulus of elasticity, splitting tensile strength and toughness are extremely affected by the geometry of fibers because the network of fibers formed and their density depends on the size and shape of fibers. Where the values of micro steel fibers are far outweighing the values of hooked end fibers. It was also deduced from empiricism results that combining long and short fibers gives excellent results.

Mechanical Properties of Hybrid Nylon-Steel- and Steel-Fibre-Reinforced High Strength Concrete at Low Fibre Volume Fraction

2010 ◽  
Vol 168-170 ◽  
pp. 1704-1707 ◽  
Author(s):  
Ming Kun Yew ◽  
Othman Ismail
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

The mechanical properties of hybrid nylon-steel-fiber-reinforced concrete were investigated in comparison to that of the steel-fiber-reinforced concrete, at the same volume fraction (0.5%). The combining of fibers, often called hybridization is investigated in this paper for a very high strength concrete of an average compressive strength of 105 MPa. Test results showed that fibers when used in a hybrid nylon-steel fibers reinforced concrete form could result in superior composite performance compared to steel-fiber-reinforced concrete. The basic property of the hybridized material that was evaluated and analyzed extensively was the modulus of rupture (MOR) and splitting tensile while the compressive strength was only slightly decreased compared to single steel fiber reinforced concrete. There is a synergy effect in the hybrid fibers system.

scholarly journals Effect of High Temperature on the Mechanical Properties of Steel Fiber-Reinforced Concrete

Fibers ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 100 ◽  
Author(s):  
Augusto C. S. Bezerra ◽  
Priscila S. Maciel ◽  
Elaine C. S. Corrêa ◽  
Paulo R. R. Soares Junior ◽  
Maria T. P. Aguilar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Temperature ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
High Temperature Treatment ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Aspect Ratios

The effect of high temperature on the mechanical properties of concrete reinforced by steel fibers with various aspect ratios has been investigated in this study. Concrete specimens were fabricated from four different concrete mixtures and cured for 28 days. After curing and natural drying, the specimens were annealed at a temperature of 500 °C for 3 h in an electric furnace. The compressive and tensile strengths as well as the elastic moduli of the produced specimens were determined. It was found that the mechanical properties (especially flexural toughness) of steel fiber-reinforced concrete were less affected by high temperature as compared to those of control concrete specimens. The flexural tensile strength of fiber-reinforced concrete measured after high-temperature treatment was almost equal to the value obtained for the reference concrete specimen at room temperature. It should be noted that the addition of steel fibers to concrete preserves its mechanical properties after exposure to a temperature of 500 °C due to fire for a period of up to 3 h, and thus is able to improve its high-temperature structural stability. The test results of this study indicate that the use of steel fibers in concrete-based materials significantly enhances their fire and hear-resistant characteristics.

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