Research on Long-Term Expansive Deformation of Steel Fiber Reinforced Expansive Concrete

2009 ◽  
Vol 417-418 ◽  
pp. 945-948
Author(s):  
Huan An He ◽  
You Gang Wang
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Expansive Concrete ◽  
Steel Bar

The inherent low tensile strength and shrinkage result in cracking of concrete under work loads. A new way to improve cracking properties is distributing steel fibers into expansive concrete to form a type of composite which is called steel fiber reinforced expansive concrete. This type of high performance concrete could compensate shrinkage as well as improving crack strength. For this concrete, the key point to ensure high performance and safety of concrete structure is to keep a stable expansive deformation during long-term service. A series of tests were carried out to measure long-term restrained expansive deformations of steel fiber reinforced expansive concrete with ages under various restrictions like steel bars and steel fibers. The test investigated some 3-year specimens. For all specimens, test parameters included 2 ratios of steel bar reinforcement, 4 volume fractions of steel fiber and 4 dosages of expansion admixture. The test results showed that the expansion of concrete decreased with increasing of steel bar reinforcing ratio as well as steel fiber volume fraction. In addition, when being in a lower dosage of expansion admixture, the specimens presented remarkable retraction of the expansive deformation. However, when beyond a certain dosage of expansion admixture, the long-term expansive deformation had less change with ages and almost remained the same with 90-day deformation, namely less losses of deformation. Hence, for steel fiber reinforced expansive concrete, using an appropriate dosage of expansion admixture could meet the requirements of designed strengthening and compensating shrinkage.

Study on Long-Term Expansive Deformation of Self-Stressing Concrete with Combined Restrictions of Steel Fibers and Steel Bar

2010 ◽  
Vol 452-453 ◽  
pp. 533-536 ◽  
Author(s):  
Huan An He ◽  
Wei Dong ◽  
Zhi Min Wu
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Expansive Concrete

Self-stressing concrete is sort of expansive concrete with high expansion energy which can induce prestresses with restriction in concrete, and steel fibers also enhance tensile strength of concrete. The combination of these two high performance concrete can be used to improve the cracking resistance of concrete significantly. However, like mechanical prestressed concrete, a stable long-term prestresses (self-stresses) level is a key to exploit the particular advantage of steel fiber reinforced self-stressing concrete. Self-stresses are created by restricting the expansion of self-stressing concrete with steel bars or/and steel fibers, therefore, in this paper a series of tests on long-term expansive deformation of concrete were carried out by means of measuring restrict expansive deformation of self-stressing concrete with restriction of steel fibers. The results of tests showed, based on the three-year recording, that the expansive deformation of steel fiber reinforced self-stressing concrete almost kept the same as that of 28-day without remarkable rebound which indicated that losses of self-stresses were not significant and can meet the design requirements on self-stresses level. In addition, it is proposed on the relationship between restrict expansive deformation and reinforcement ratio of steel rebars under different steel fiber volume fraction from 0-2%.

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.

Flexural Toughness of Hybrid Fiber Reinforced High-Performance Concrete under Three-Point Bending

2013 ◽  
Vol 357-360 ◽  
pp. 1110-1114
Author(s):  
Dong Tao Xia ◽  
Xiang Kun Liu ◽  
Bo Ru Zhou
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Fiber Volume ◽  
Flexural Toughness

A set of new hybrid fiber reinforced high-performance concrete was developed and studied by experiment. The fibers incorporated the concrete are the collection of the steel fiber, modified polypropylene fiber and polypropylene with total fiber content not more than 1%. And the compressive test, splitting tensile test and the flexural toughness test were performed on eight groups of specimens. Based on the load-deflection and load-CMOD curves and the equivalent flexural tensile strength, the effect of fiber volume fraction and hybrid mode upon concrete's mechanical properties and post-peak behavior were investigated. The test results show that the mixing of the three different fibers can increase concrete's splitting tensile strength and flexural toughness more effectively with no significantly effect on compressive strength. The mixture of the three different fibers exist the optimization problem. Based on the results of the analysis, the compatible proportion of the three fibers is 0.7% steel fiber, 0.19% modified polypropylene fiber and 0.11% polypropylene fiber.

scholarly journals Experimental Study on Shear Performance of Cast-In-Place Ultra-High Performance Concrete Structures

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3254 ◽  
Author(s):  
Li ◽  
Feng ◽  
Ke ◽  
Pan ◽  
Nie
Keyword(s):  
Shear Strength ◽  
High Performance ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Steel Fibers ◽  
Direct Shear ◽  
Ultra High Performance Concrete ◽  
Fiber Volume

In order to study the direct shear properties of ultra-high performance concrete (UHPC) structures, 15 Z-shaped monolithic placement specimens (MPSs) and 12 Z-shaped waterjet treated specimens (WJTSs) were tested to study the shear behavior and failure modes. The effects of steel fiber shape, steel fiber volume fraction and interface treatment on the direct shear properties of UHPC were investigated. The test results demonstrate that the MPSs were reinforced with steel fibers and underwent ductile failure. The ultimate load of the MPS is about 166.9% of the initial cracking load. However, the WJTSs failed in a typical brittle mode. Increasing the fiber volume fraction significantly improves the shear strength, which can reach 24.72 MPa. The steel fiber type has little effect on the shear strength and ductility, while increasing the length of steel fibers improves its ductility and slightly reduces the shear strength. The direct shear strength of the WJTSs made from 16 mm hooked-type steel fibers can reach 9.15 MPa, which is 2.47 times the direct shear strength of the specimens without fibers. Finally, an interaction formula for the shear and compressive strength was proposed on the basis of the experimental results, to predict the shear load-carrying capacity of the cast-in-place UHPC structures.

Experimental Study of Strengthening and Toughening for Recycled Steel Fiber Reinforced Ultra-High Performance Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 104-111 ◽  
Author(s):  
Gai Fei Peng ◽  
Xu Jing Niu ◽  
Qian Qian Long
Keyword(s):  
Mechanical Properties ◽  
Fracture Energy ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Ultra High Performance Concrete ◽  
Tensile Splitting Strength ◽  
Recycled Steel

This paper presents an experimental investigation on mechanical properties (including compressive strength, tensile splitting strength and fracture energy) of ultra-high performance concrete (UHPC) with recycled steel fiber, compared with none fiber and industrial steel fiber reinforced UHPC. Moreover, the microscopic observation of fracture energy was carried out. All specimens were prepared at 0.18 water /binder (W/B) ratio and the dosage of steel fiber was controlled at 60 kg/m3. The results indicate that recycled steel fiber has a significant effect on enhancing strength and toughness of UHPC. And owing to the crimped shape, higher tensile strength (1800-2000 MPa) and appropriate diameter (1 mm) of recycled steel fiber, the steel fibers of UHPRSFRC will not immediately be pulled off and necking phenomenon is distinct.

scholarly journals Dynamic Stress-Strain Behaviour of Steel Fiber Reinforced High-Performance Concrete with Fly Ash

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tan Chien Yet ◽  
R. Hamid ◽  
Mudiono Kasmuri
Keyword(s):  
Fly Ash ◽  
Strain Rate ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Engineering Properties ◽  
Fiber Reinforced ◽  
Dynamic Impact ◽  
Static Compression

The addition of steel fibers into concrete mix can significantly improve the engineering properties of concrete. The mechanical behaviors of steel fiber reinforced high-performance concrete with fly ash (SFRHPFAC) are studied in this paper through both static compression test and dynamic impact test. Cylindrical and cube specimens with three volume fractions of end-hooked steel fibers with volume fraction of 0.5%, 1.0%, and 1.5% (39.25, 78.50, and 117.75 kg/m3) and aspect ratio of 64 are used. These specimens are then tested for static compression and for dynamic impact by split Hopkinson pressure bar (SHPB) at strain rate of 30–60 s−1. The results reveal that the failure mode of concrete considerably changes from brittle to ductile with the addition of steel fibers. The plain concrete may fail under low-strain-rate single impact whereas the fibrous concrete can resist impact at high strain rate loading. It is shown that strain rate has great influence on concrete strength. Besides, toughness energy is proportional to the fiber content in both static and dynamic compressions.

Development on the Corrosion of Steel Fiber and Prevention in the Ultra-High Performance Concrete (UHPC)

2021 ◽  
Vol 1036 ◽  
pp. 358-370
Author(s):  
Zhen Wen Guo ◽  
Xin Zhi Duan ◽  
Qiang Wang ◽  
Si Jia Wang ◽  
Xiao Lu Guo
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Chloride Ions ◽  
Control Methods ◽  
Ultra High Performance Concrete ◽  
Hybrid Fibers ◽  
Steel Bar ◽  
Corrosion Of Steel

Chloride ions, water, and oxygen could cause the corrosion of steel fiber in the aggressive environment. The corrosion of steel fiber in UHPC is a long-term process and the rate is very slow. As one of the important components of ultra-high performance concrete (UHPC), the corrosion of steel fiber is the result of multiple factors. The characteristics of steel fiber corrosion in UHPC, the factors influencing the corrosion of steel fiber in UHPC (including nanomaterials, curing condition and crack width), and effects of steel fiber corrosion on the UHPC performance (including mechanical properties, matrix rehydration and corrosion of steel bar), are emphatically elaborated. And the control methods of steel fiber corrosion in UHPC are briefly introduced, i.e. hybrid fibers and stainless steel fibers.

Performance on Steel Fiber Reinforced Self-Stressing Concrete

2008 ◽  
Vol 400-402 ◽  
pp. 427-432
Author(s):  
Huan An He ◽  
Bo Xin Wang ◽  
Jian Ting Lin
Keyword(s):  
Tensile Strength ◽  
Prestressed Concrete ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
The Troubles ◽  
Steel Bars ◽  
Steel Fiber Concrete

In this paper 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, self-stresses are generated in concrete under combined restriction of steel bars as well as steel fibers. Thank to the pre-stresses tensile strength of concrete are significantly increased as well as cracking strength. In addition, on the one hand, expansive deformation of SFFRSSC can compensate the shrinkage of concrete to decrease non-loaded cracks resulting from shrinkage, and even when cracking, the steel fibers play an important role in resistance to crack development. On the other hand, self-stressing concrete can avoid the troubles of construction compared with conventional mechanical prestressed concrete. Therefore, above-mentioned advantages of SFFRSSC over ordinary concrete imply a better prospect in using SFFRSSC in civil engineering. For purpose of understanding the properties of SFFRSSC, in this paper some researches were carried out to investigate the special expansive behaviors with ages and tensile strength. The test results indicated that at early age the expansion of SFFRSSC developed rapidly but 14 day the 90% of overall expansive deformation basically fulfilled and subsequently expansion kept stable. Axial tensile test result showed that tensile strength were improved 2-3 times for self-stressing concrete specimens restrained by steel bars as well as steel fibers.

Experimental Study on Mechanical Properties of Steel Fiber Reinforced High Performance Concrete

2013 ◽  
Vol 859 ◽  
pp. 56-59 ◽  
Author(s):  
Yong Qiang Ma
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced

A large number of experiments have been carried out in this study to reveal the effect of the steel fiber dosage on the mechanical properties of HPC (high performance concrete). The mechanical property includes compressive strength, elastic modulus and flexural strength. The results indicate that the addition of steel fiber increase the compressive strength, elastic modulus and flexural strength of HPC. When the steel fiber dosage is less than 2%, these mechanical property parameters are increasing gradually with the increase of steel fiber dosage, while these parameters begin to decrease when the steel fiber dosage is more than 2%. With the development of HPC, the application of steel fibers in HPC becomes more and more popular. In the actual construction of steel fiber reinforced HPC, the dosage of steel fiber should be controlled strictly in order to ensure that the steel fibers can perform their best improvement on high performance concrete.

scholarly journals Bond of Ribbed Steel Bar in High-Performance Steel Fiber Reinforced Expanded-Shale Lightweight Concrete

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 582
Author(s):  
Mingshuang Zhao ◽  
Guirong Liu ◽  
Lingli Liu ◽  
Yanyan Zhang ◽  
Kang Shi ◽  
...  
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Bond Stress ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Steel Bar ◽  
Expanded Shale

For the structural application of high-performance Steel Fiber Reinforced Expanded-shale Lightweight Concrete (SFRELC), a reliable bond of ribbed steel bar should be ensured. In this paper, an experimental study was carried out on the bond properties of ribbed steel bar embedded in SFRELC by the direct pull-out test. The SFRELC was produced with a strength grade of 35 MPa and a volume fraction of steel fiber as 0%, 0.8%, 1.2%, 1.6% and 2.0%, respectively. Fifteen groups of specimens were made with a central placed steel bar with diameter of 14 mm, 20 mm and 28 mm, respectively. Complete bond stress-slip curves were determined for each group of specimens, and the characteristic values of bond-stress and slip at key points of the curves were ascertained. Results show that the bond strength, peak-slip and residual bond strength increased with the increase of the volume fraction of steel fiber. With the increase of steel bar diameter, bond strength decreased while the peak-slip increased, and the descending curves became sharp with a decreased residual bond strength. Formulas for calculating the bond strength and peak-slip were proposed. The relationships were determined for the splitting bond strength, residual bond strength with the bond strength, the splitting bond slip and residual bond slip with the peak-slip. Combined with rational fitting analyses of bond strength and slip, a constitutive model was selected for predicting the bond stress-slip of ribbed steel bar in SFRELC.

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