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.

scholarly journals Development of Steel Fiber-Reinforced Expanded-Shale Lightweight Concrete with High Freeze-Thaw Resistance

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mingshuang Zhao ◽  
Xiaoyan Zhang ◽  
Wenhui Song ◽  
Changyong Li ◽  
Shunbo Zhao
Keyword(s):  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Content Volume ◽  
Steel Fibers ◽  
Fine Aggregate ◽  
Test Results ◽  
Fiber Reinforced ◽  
Freeze Thaw ◽  
Expanded Shale

For the popularized structural application, steel fiber-reinforced expanded-shale lightweight concrete (SFRELC) with high freeze-thaw resistance was developed. The experimental study of this paper figured out the effects of air-entraining content, volume fraction of steel fibers, and fine aggregate type. Results showed that while the less change of mass loss rate was taken place for SFRELC after 300 freeze-thaw cycles, the relative dynamic modulus of elasticity and the relative flexural strength presented clear trends of freeze-thaw resistance of SFRELC. The compound effect of the air-entraining agent and the steel fibers was found to support the SFRELC with high freeze-thaw resistance, and the mechanisms were explored with the aid of the test results of water penetration of SFRELC. The beneficial effect was appeared from the replacement of lightweight sand with manufactured sand. Based on the test results, suggestions are given out for the optimal mix proportion of SFRELC to satisfy the durability requirement of freeze-thaw resistance.

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.

scholarly journals Complete Stress–Strain Curves of Self-Compacting Steel Fiber Reinforced Expanded-Shale Lightweight Concrete under Uniaxial Compression

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2979 ◽  
Author(s):  
Zhao ◽  
Zhang ◽  
Shang ◽  
Fu ◽  
Zhang ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Compressive Strain ◽  
Strain Curve ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Expanded Shale

To expand the structural application of steel fiber reinforced expanded-shale lightweight concrete (SFRELC), a self-compacting SFRELC with high-workability was developed based on previous research. As part of the investigation, the present study focuses on the adaptability of formulas used for the complete stress–strain curves of steel fiber reinforced lightweight-aggregate concrete and conventional concrete under uniaxial compression. On the basis of mix proportion of SFRELC, self-compacting SFRELC was designed with the volume fraction of steel fiber as 0%, 0.4%, 0.8%, 1.2%, 1.6%, and 2.0%. Eighteen cylindrical specimens with dimensions of Φ150 mm × 300 mm were tested to measure the uniaxial compressive stress–strain curves of self-compacting SFRELC. Results indicated that, with the increasing volume fraction of steel fiber, the compressive strain at the peak-stress of the stress–strain curve increased, while the slope of the descending portion decreased. This increased the energy absorption of self-compacting SFRELC with a higher compression toughness. With a comparison of test results between four groups of calculation models, a group of formulas is selected to express the complete stress–strain curves of self-compacting SFRELC under uniaxial compression.

Bond Properties of Plain Steel Bar in Concrete with Machine-Made Sand

2013 ◽  
Vol 438-439 ◽  
pp. 20-24
Author(s):  
Feng Lan Li ◽  
Ke Fei Yu ◽  
Xin Xin Ding ◽  
Chang Ming Li
Keyword(s):  
Bond Strength ◽  
Experimental Studies ◽  
Bond Stress ◽  
Test Method ◽  
Bond Properties ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Pull Out ◽  
Steel Bar

To meet the requirement of machine-made sand application in concrete structures, it is necessary to understand the bond properties of steel bar with machine-made sand concrete (MSC). Therefore, the experimental studies were carried out on the bond of plain steel bar with MSC by the central pull-out test method. Three specimens were cast as one group, 6 groups were tested considering the changes of strength grade of MSC and ordinary concrete. The bond-slip curves were measured and analyzed. The results show that the bond slip begins at the tensile side and transfers gradually to the free end before the entire slip turns up along the interface of plain steel bar and surrounded concrete, the largest average bond stress, i. e. the bond strength of plain steel bar corresponds to the initial entire slip of plain steel bar. With the increasing strength grade of MSC and ordinary concrete, the difference of slip at tensile side and free end becomes greater. Comparing that only appears in ordinary concrete with higher strength, the larger slips turn up while the bond stress reaches the largest for the plain steel bar in MSC. Larger scatter of bond strength is between specimens in the same group. Some plain steel bars yields with the beginning of entire slip along the interface.

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.

scholarly journals The Effect of Steel Fibers Type and Content on the Development of Fresh and Hardened Properties and Durability of Selfconsolidating Concrete

2021 ◽  
Author(s):  
Nirmal Tamrakar
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Ring Test ◽  
Fiber Reinforced ◽  
Chloride Permeability ◽  
Freeze Thaw

Steel fiber reinforced self-consolidated concrete (SFRSCC) has the advantages of both selfconsolidated concrete and fiber reinforced concrete. Thirteen concrete mixtures (with short and long steel fiber) were prepared including control mix. The steel fiber volume fraction varied from 0 to 2.4% by the volume of concrete. The fresh properties of SCC were evaluated using slump flow test, J-ring test, V-funnel test and L-Box test. Bond strength, compressive strength and flexural tests were performed in order to investigate mechanical properties. Water sorptivity, water absorption and porosity, rapid chloride permeability test (RCPT), corrosion and freezethaw cycles tests were performed in order to investigate the durability properties. Bond strength gain of 244% with respect to control mix was observed. Moreover, the compressive strength and MOR gained 45% and 127%, respectively. There was no significant weight loss of the concrete specimen after freeze-thaw cycles for concrete mixture with steel fibers. However, flexural toughness was reduced after freeze-thaw cycles.

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.

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