scholarly journals Compressive and Diagonal Tension Strengths of Masonry Prisms Strengthened with Amorphous Steel Fiber-Reinforced Mortar Overlay

2021 ◽  
Vol 11 (13) ◽  
pp. 5974
Author(s):  
Ji-Hoon Yu ◽  
Ji-Hun Park
Keyword(s):  
Bond Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Low Cost ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Initial Strength ◽  
Shear Connectors ◽  
Tension Tests ◽  
Amorphous Steel

A technique for strengthening masonry walls by plastering with amorphous steel fiber-reinforced mortar (ASFRM) is investigated through compressive and diagonal tension tests for masonry prisms. The vertical joint between masonry units was not completely filled with mortar to mimic poor workmanship, which is typically reflected in low-cost buildings. The test variables include the number and thickness of mortar overlays, fiber volume fraction, and additional reinforcement using glass fiber mesh or shear connectors. In most strengthened specimens, the ASFRM is not damaged but separated from the masonry prisms after its maximum strength is reached. Additional tests for the bond strength between the ASFRM overlay and masonry surface are conducted to evaluate its contribution to the strengthening effects. Based on experimental observations, equations for predicting the compressive and diagonal tension strengths of masonry prisms strengthened with ASFRM are proposed. The compressive strength can be predicted more accurately by considering the asymmetrical distribution of compressive stress when strengthening is performed on only one side. The diagonal tension strength after strengthening can be predicted by incorporating the contribution of the bond strength between the ASFRM overlay and masonry prism to the initial strength.

scholarly journals Investigation of Steel Fiber-Reinforced Mortar Overlay for Strengthening Masonry Walls by Prism Tests

2020 ◽  
Vol 10 (18) ◽  
pp. 6395
Author(s):  
Ji-Hoon Yu ◽  
Ji-Hun Park
Keyword(s):  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Masonry Walls ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Red Clay ◽  
Design Formula ◽  
Mixing Ratios ◽  
Tension Tests

A strengthening method using steel fiber-reinforced mortar (SFRM), proposed for the seismic retrofit of masonry buildings, is verified experimentally in this study. The SFRM is overlaid on masonry walls directly, which is possible to implement while the building is occupied for residence. First, tests of workability and material strengths were conducted for SFRM itself in order to find SFRM mixing ratios appropriate for overlay construction and strengthening. Then, masonry prisms were produced using two types of bricks and strengthened with SFRM for the chosen mixing ratios and test variables such as the number of overlaid sides and the fiber volume fraction. Compressive strength tests and diagonal tension tests for those specimens were conducted. Both compressive and shear strengths were improved the most highly by overlaying the SFRM with a fiber volume fraction of 1.3%, which is the highest among the test variables, on both sides. Overlaid SFRM tends to be detached without cracking almost at the maximum strength in both compression and diagonal tension tests. For red clay brick prisms, the compressive and shear strengths increased by up to 61% and 138%, respectively. For concrete brick prisms, the compressive and shear strengths increased by up to 26% and 67%. Finally, a design formula for the shear strength of strengthened masonry prisms is compared with the experimental results, and it is observed that the design formula gives slightly higher results.

scholarly journals Using Steel Fiber-Reinforced Concrete Precast Panels for Strengthening in Shear of Beams: An Experimental and Analytical Investigation

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Pitcha Jongvivatsakul ◽  
Linh V. H. Bui ◽  
Theethawachr Koyekaewphring ◽  
Atichon Kunawisarut ◽  
Narawit Hemstapat ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Simple Formulation

In this paper, the performances of reinforced concrete (RC) beams strengthened in shear with steel fiber-reinforced concrete (SFRC) panels are investigated through experiment, analytical computation, and numerical analysis. An experimental program of RC beams strengthened by using SFRC panels, which were attached to both sides of the beams, is carried out to investigate the effects of fiber volume fraction, connection type, and number and diameter of bolts on the structural responses of the retrofitted beams. The current shear resisting model is also employed to discuss the test data considering shear contribution of SFRC panels. The experimental results indicate that the shear effectiveness of the beams strengthened by using SFRC panels is significantly improved. A three-dimensional (3D) nonlinear finite element (FE) analysis adopting ABAQUS is also conducted to simulate the beams strengthened in shear with SFRC panels. The investigation reveals the good agreement between the experimental and analytical results in terms of the mechanical behaviors. To complement the analytical study, a parametric study is performed to further evaluate the influences of panel thickness, compressive strength of SFRC, and bolt pattern on the performances of the beams. Based on the numerical and experimental analysis, a shear resisting model incorporating the simple formulation of average tensile strength perpendicular to the diagonal crack of the strengthened SFRC panels is proposed with the acceptable accuracy for predicting the shear contribution of the SFRC system under various effects.

J Integral of Steel Fiber Reinforced High Strength Concrete

2012 ◽  
Vol 476-478 ◽  
pp. 1568-1571
Author(s):  
Ting Yi Zhang ◽  
Guang He Zheng ◽  
Ping Wang ◽  
Kai Zhang ◽  
Huai Sen Cai
Keyword(s):  
High Strength Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Three Point Bending ◽  
Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.

Mechanical Property of Hybrid Steel Fiber Reinforced Cement-Based Composites

2013 ◽  
Vol 539 ◽  
pp. 99-102
Author(s):  
Hai Tao Tan ◽  
Wu Yao ◽  
Xiao Ming Song ◽  
Shuai Dong
Keyword(s):  
Mechanical Property ◽  
Fracture Energy ◽  
Fiber Volume Fraction ◽  
Ultimate Load ◽  
Bending Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Reinforced Cement

The ultimate load, fracture energy and equivalent bending strength of hybrid steel fiber reinforced mortar were investigated with a constant fiber volume fraction in this paper. The results showed that ultimate load of hybrid steel-fiber reinforced mortar was higher than that of mono-fiber reinforced mortar; fracture energy and equivalent bending strength increased with the volume fraction of steel fiber with end hooks.

Shrinkage Performance of Adherence of New Steel Fiber-Reinforced Concrete to Old Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 3569-3574
Author(s):  
Hong Qiang Cheng ◽  
Dan Ying Gao
Keyword(s):  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Volume ◽  
Shrinkage Force ◽  
The Difference

Shrinkage experiments were done to determine the influence of the volume fraction of steel fiber-reinforcement on the bonding behavior between new concrete and old concrete. The mechanics of the model of restricted shrinkage upon the adherence of new steel fiber reinforced concrete to old concrete are described. The results demonstrate that the difference of shrinkage between the new and the old concrete can been reduced by adding steel fiber to the new concrete. The decrease of shrinkage difference reduces the shrinkage force at the adhesive interface, which improves the adhesion of new concrete to old concrete and the magnitude of the decrease of shrinkage difference is correlated to the steel fiber volume fraction.

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.

Improvement of Impact Resistance of Synthetic Macro-Fiber Reinfored Concrete

2014 ◽  
Vol 578-579 ◽  
pp. 501-504
Author(s):  
Guo Chao Wang ◽  
Bo Xin Wang
Keyword(s):  
Reinforced Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Polypropylene Fibers ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
The Impact

The incorporation of a small amount of steel fibers or fine polypropylene fibers in concrete can increase its impact resistance. But steel fiber has the problems of corrosion, high cost and high mess. The effect of fine polypropylene fibers in inhibiting the impact crack is not effective. The research was taken to measure the properties of fresh concrete mixture of Synthetic Macro-fiber reinforced concrete. And investigated the influence of fiber length and volume fraction on the impact resistance of Synthetic Macro-fiber reinforced concrete. The results showed that these fibers could obviously improve the impact resistance of concrete. There was a best Synthetic Macro-fiber volume fraction. The length of the Synthetic Macro-fiber had a certain influence on the impact resistance of 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.

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%.

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.

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