Behavior of High Performance Steel-Fiber Concrete Exposed to High Temperature in Terms of Spalling and Permeability

2014 ◽  
Vol 629-630 ◽  
pp. 252-258 ◽  
Author(s):  
Gai Fei Peng ◽  
Xu Jie Duan ◽  
Xue Chao Yang ◽  
Ting Yu Hao
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Plain Concrete ◽  
Thermal Exposure ◽  
Explosive Spalling ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
High Performance Steel

An experimental investigation was conducted on behavior of high performance steel-fiber concrete subjected to high temperature, in terms of explosive spalling and permeability. A series of concretes incorporated steel fiber at various dosages were prepared, and further processed to have a series of moisture contents. Explosive spalling tests were conducted on control plain concrete and steel fiber concrete. After explosive spalling tests, each of the specimens that didn’t encounter spalling was sawn into two pieces. Crack observations and permeability tests were conducted on the sawn surfaces. The results prove that steel fiber is efficient to avoid spalling concrete under high temperature. The permeability increases significantly after thermal exposure, while it also exhibits an ascending trend with the increase of moisture content. Therefore it is concluded that steel fiber can play a positive effect on explosive spalling of high performance concrete under high temperature, as well as on permeability after thermal exposure.

scholarly journals Mechanical properties of various concrete after high temperature exposure Mechanical property of various types of concrete after high temperature exposure is investigated. Considering compressive strength requirement for a vertical element in high rise building, concrete specimens with various design strengths of 35, 80, 100, and 150 MPa were tested. Particularly, the influence of incorporated steel fiber on fire resistance is of interest in this study. Experimental results show that the fire resistance depends on the design strength and steel fiber content. Normal strength concrete (NSC) of a design strength of 35 MPa or high performance concrete (HPC) of 80-100 MPa does not spall when exposed to 100-400 °C of temperature. However, an explosive spalling occurs at 300 °C when the HPCs contain 1 vol.% of steel fiber. Ultra-high performance concrete (UHPC) of a design strength of 150 MPa and 1.5 vol.% of steel fiber also shows dramatic spalling at 300 °C. The experimental results found in this study can contribute to a better understanding of the behaviors of HPC and UHPC under fire and the role of steel fiber on the fire resistance.

2017 ◽  
Keyword(s):  
High Temperature ◽  
Fire Resistance ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Experimental Results ◽  
Explosive Spalling ◽  
Design Strength ◽  
High Temperature Exposure ◽  
Temperature Exposure

Reinforcement and Fiber to Induce Ductile Behavior of Ultra High Performance Steel Fiber Concrete

2013 ◽  
Vol 351-352 ◽  
pp. 199-202
Author(s):  
Heng Dong ◽  
Su Li Feng
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Ultra High Performance Concrete ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
Reinforcement Bar ◽  
Ductile Behavior

To induce the ductile behavior of ultra high performance concrete beams, the experiments to find out the best composition of volume fraction of steel fiber and ratio of reinforcement bar were carried out. 15 UHPC beams which have various combinations of volume fraction of steel fiber and ratio of reinforcement bar. The reinforcement bars was consist of 2×1, 3×3, 4×4, 5×4. The volume fractions of steel fibers were 0%, 0.7%, 1%, 1.5%, 2%. The beam which has 0% volume fraction with the close placement reinforcement bar has little effect on ductile behavior. At least 0.7% volume fraction with the close placement reinforcement bar guarantees the ductile behavior of UHPC beam.

scholarly journals Variation of the Pore Morphology during the Early Age in Plain and Fiber-Reinforced High-Performance Concrete under Moisture-Saturated Curing

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 975 ◽  
Author(s):  
Miguel Vicente ◽  
Jesús Mínguez ◽  
Dorys González
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Plain Concrete ◽  
Early Age ◽  
Geometrical Parameters ◽  
Pore Morphology ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
The One

In this paper, two concrete mixtures of plain concrete (PC) and steel fiber-reinforced high-performance concrete (SFRC) have been scanned in order to analyze the variation of the pore morphology during the first curing week. Six cylinders of 45.2-mm diameter 50-mm height were performed. All of the specimens were kept in a curing room at 20 °C and 100% humidity. A computed tomography (CT) scan was used to observe the internal voids of the mixtures, and the data were analyzed using digital image processing (DIP) software, which identified and isolated each individual void in addition to extracting all of their geometrical parameters. The results revealed that the SFRC specimens showed a greater porosity than the PC ones. Moreover, the porosity increased over time in the case of SFRC, while it remained almost constant in the case of PC. The porosity increased with the depth in all cases, and the lowest porosity was observed in the upper layer of the specimens, which is the one that was in contact with the air. The analysis of the results showed that the fibers provided additional stiffness to the cement paste, which was especially noticeable during this first curing week, resulting in an increasing of the volume of the voids and the pore size, as well as a reduction in the shape factor of the voids, among other effects.

The Influence on High-Temperature Mechanical Properties of Hybrid-Fiber-Reinforced High-Performance Concrete and Microscopic Analysis

2012 ◽  
Vol 226-228 ◽  
pp. 1709-1713
Author(s):  
Lan Yan ◽  
Y.M. Xing ◽  
Ji Jun Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Transition Zone ◽  
High Performance ◽  
Room Temperature ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Interfacial Transition Zone ◽  
Hybrid Fiber ◽  
High Temperature Mechanical Properties

This paper investigated the high temperature mechanical properties of the hybrid fiber reinforced high performance concrete (HFHPC) and normal concrete (NC) .After being subjected to different elevated heating temperatures, two kinds of concretes have been tested for the compressive strength, splitting tensile strength and flexural strength of test specimen at room temperature and 200 °C,400 °C,600 °C,800 °C.Microstructure changes of concrete were also observed by using Scanning Electron Microscopy (SEM) after high temperature. The results show that the hybrid fiber can significantly increase mechanical properties of the concrete at room temperature and high temperature. SEM and XRD analysis shows that there is a permeable diffusion layer in the steel fiber surface because of solid state reaction in the Interfacial Transition Zone of steel fiber and concrete. This permeable diffusion layer is white, bright, serrated and mainly consist of FeSi2 and the complex hydrated calcium silicate. The compounds of this layer change the Interfacial Transition Zone structure, enhance bonding capacity of the steel fiber and matrix, and increase the high temperature mechanical properties of concrete.

Study on Restrained Expansive Deformation of Steel Fiber Reinforced Self-Stressing Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 305-308
Author(s):  
Huan An He ◽  
Cheng Kui Huang
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
The Troubles ◽  
Steel Bar ◽  
Steel Bars ◽  
Steel Fiber Concrete

A new sort of high performance concrete is introduced which combines most advantages of prestressed concrete and steel fiber concrete, named steel fiber reinforced self-stressing concrete(SFFRSSC for short). Self-stressing concrete is actually a kind of expansive concrete which self-stresses, namely pre-compressive stresses, are induced by dint of some restrictions generally provided by steel bars to concrete expansion after hydration of expansive cement. As a result of chemical reaction, concrete archived prestresses by itself different from mechanical prestressed concrete, so called self-stressing concrete. By distributing short-cut steel fibers into self-stressing concrete at random, prestresses( self-stress) are created in concrete under combined restriction of steel bars and steel fibers. Thank to the pre-stresses tensile strength of concrete are significantly increased as well as cracking strength. In addition, expansive deformation of SFFRSSC can compensate the shrinkage of concrete to decrease shrinkage crack, and the steel fibers play an important role in post-crack behavior. On the other hand, self-stressing concrete can avoid the troubles of construction compared with conventional mechanical prestressed concrete. For purpose of understanding the properties of SFFRSSC, in this paper some researches were carried out to investigate the special expansive behaviors of restrained expansive deformation with restriction of steel bar as well as steel fiber. The test results indicated that steel bar and steel fiber both provide effective restrict to self-stressing concrete as result of forming prestresses in concrete.

Shear Strength of Steel Fiber Concrete - Plain Concrete Composite Beams

2015 ◽  
Vol 27 (5) ◽  
pp. 501-510
Author(s):  
Chul-Goo Kim ◽  
Hong-Gun Park ◽  
Geon-Ho Hong ◽  
Su-Min Kang
Keyword(s):  
Shear Strength ◽  
Steel Fiber ◽  
Plain Concrete ◽  
Composite Beams ◽  
Fiber Concrete ◽  
Steel Fiber Concrete

The Mechanism of Explosive Spalling and Measures to Resistant Spalling of Concrete Exposed to High Temperature by Incorporating Fibers: A Review

2010 ◽  
Vol 168-170 ◽  
pp. 773-777 ◽  
Author(s):  
Juan Yang ◽  
Gai Fei Peng
Keyword(s):  
High Strength Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Hybrid Fiber ◽  
Explosive Spalling ◽  
Preliminary Study ◽  
Experimental Researches

Many experimental researches have been conducted on explosive spalling performance of concrete of high-strength / high performance concrete (HSC/HPC). This paper summarizes two main explosive spalling mechanisms (Vapor pressure build-up mechanism and Thermal stress mechanism) of concrete at elevated temperature, and also presents the measures to resistant the explosive spalling, i.e. by incorporating fibers (polypropylene fiber(PPF), steel fiber(SF) and hybrid fiber of the first two). Finally, the further studies of both the mechanism and the measures are proposed. Also, the preliminary study of ultra high-strength concrete (UHSC) on fire-resistance are mentioned.

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