scholarly journals Effects of Shrinkage-Compensation on Mechanical Properties and Repair Performance of Strain-Hardening Cement Composite Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Seok-Joon Jang ◽  
Sun-Woo Kim ◽  
Wan-Shin Park ◽  
Koichi Kobayashi ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Structural Performance ◽  
Rc Beam ◽  
Test Results ◽  
Fiber Volume ◽  
Study Results ◽  
Shrinkage Compensation

This paper describes the effects of expansive admixture on the mechanical properties of strain-hardening cement-based composite (SHCC) mixtures. Also, this study investigates structural performance of reinforced concrete (RC) beam specimens repaired with SHCC and Ex-SHCC (SHCC with expansive admixture). In this study, SHCC and Ex-SHCC mixtures with two specified compressive strength values of 30 MPa and 60 MPa and the fiber volume fraction of 1.5% were investigated. The expansive admixture replacement ratio of 10% by cement weight was used in this study. The test results indicate that the compressive, tensile, and flexural strength values of the SHCC mixtures increased when expansive admixture was included in the mix; however, their toughness and ductility decreased. The study results also show that the application of both SHCC and Ex-SHCC mixtures to repair damaged RC beam specimens can lead to significant structural performance improvement by mitigating crack damage and increasing ductility.

Mechanical Properties of Sprayable Fiber Reinforced Strain-Hardening Cement Composite (SHCC)

2013 ◽  
Vol 372 ◽  
pp. 211-214
Author(s):  
Zhong Jie Yu ◽  
Mi Hwa Lee ◽  
Hyun Do Yun
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Crack Opening ◽  
Cement Composite ◽  
Seismic Retrofitting ◽  
Mineral Admixtures ◽  
Uniaxial Tensile ◽  
High Expectations ◽  
The Subject

The use of strain-hardening cement composite (SHCC), which exhibits metal-like deformation behavior and has ability to restrict crack opening, as a retrofit material for seismic retrofitting of existing infrastructures, has been the subject of high expectations. In this work, Three SHCC mixtures including different chemical or mineral admixtures were prepared and evaluated based on the mechanical properties, such as flow, sprayability, compressive and uniaxial tensile performances. All SHCC mixtures were reinforced with polyvinyl alcohol (PVA) fibers at volume fraction of 2.2%. Mechanical properties of each SHCC mixture were measured and evaluated after mixing, pumping, and shotcreting. Experimental results indicated that the compressive strength and elastic modulus of three SHCC mixtures increased almost linearly according to shotcreting procedure from mixer to nozzle. And the uniaxial tensile of SHCC mixture (SHCC-AE) with AE agent was superior to the other SHCC mixtures (SHCC-MC and-N).

scholarly journals Influence of fiber size on mechanical properties of strain-hardening fiber-reinforced concrete

2020 ◽  
Vol 14 (3) ◽  
pp. 84-95
Author(s):  
Duy-Liem Nguyen ◽  
Thac-Quang Nguyen ◽  
Huynh-Tan-Tai Nguyen
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Tensile Specimen ◽  
Gauge Length ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Compressive Properties ◽  
Fiber Volume ◽  
Fiber Size

This research deals with the influences of macro, meso and micro steel-smooth fibers on tensile and compressive properties of strain-hardening fiber-reinforced concretes (SFCs). The different sizes, indicated by length/diameter ratio, of steel-smooth fiber added in plain matrix (Pl) were as follows: 30/0.3 for the macro (Ma), 19/0.2 for the meso (Me) and 13/0.2 for the micro fiber (Mi). All SFCs were used the same fiber volume fraction of 1.5%. The compressive specimen was cylinder-shaped with diameter × height of 150 × 200 mm, the tensile specimen was bell-shaped with effective dimensions of 25 × 50 × 100 mm (thickness × width × gauge length). Although the adding fibers in plain matrix of SFCs produced the tensile strain-hardening behaviors accompanied by multiple micro-cracks, the significances in enhancing different mechanical properties of the SFCs were different. Firstly, under both tension and compression, the macro fibers produced the best performance in terms of strength, strain capacity and toughness whereas the micro produced the worst of them. Secondly, the adding fibers in plain matrix produced more favorable influences on tensile properties than compressive properties. Thirdly, the most sensitive parameter was observed to be the tensile toughness. Finally, the correlation between tensile strength and compressive strength of the studied SFCs were also reported. Keywords: aspect ratio; strain-hardening; post-cracking; ductility; fiber size.

scholarly journals Investigation on the Mechanical Properties of Fiber Reinforced Recycled Concrete

2016 ◽  
Vol 2 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hasan Jalilifar ◽  
Fatholla Sajedi ◽  
Sadegh Kazemi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Experimental Test ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Content ◽  
Recycled Concrete ◽  
Test Results ◽  
Fiber Volume ◽  
Flexural Toughness

The flexural strength of conventional concrete material is known to be enhanced by incorporating a moderate volume-fraction of randomly distributed fibers. However, there is limited information on describing the influence of fiber volume-fraction on the compressive and flexural strength of recycled coarse aggregate concrete (RCA-C) material. This paper reports on experimental test results of the RCA-C material replaced with 0, 30, 50 and 100% recycled aggregate and 0, 0.5, 1 and 1.5% steel fiber volume fraction. Three-point flexural tests of notched prism specimens were completed. The mechanical properties in compression were characterized using cube specimens. Significant improvement in compressive and flexural strength of RCA-C was found as fiber content increased from 0 to 1.5%. The experimental test results of RCA-C were further evaluated to investigate the influence of fiber content on flexural toughness. According to test results, the addition of steel fibers to RCA-C material appreciably increased the flexural toughness.

Electrical Resistance Properties of Cement/Carbon Fiber Composite

2012 ◽  
Vol 560-561 ◽  
pp. 830-836 ◽  
Author(s):  
Bi Qin Dong ◽  
Feng Xing ◽  
Hong Zhi Cui ◽  
Zong Jin Li
Keyword(s):  
Carbon Fiber ◽  
Electrical Resistance ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Composite ◽  
Cement Composite ◽  
Carbon Fiber Composite ◽  
Fiber Volume ◽  
Study Results ◽  
Short Carbon

In this article, study results of the electrical resistance properties of cement/carbon fiber composite are presented. Using a normal mixing and compacting method, up to 0.85v.% short carbon fiber can be easily incorporated into the cement composite. And its electrical resistivity properties are measured. The resistivity of specimens decreases greatly with the volume fraction of fibers increasing. Moreover, it is found that there is a saturation point for fiber volume fraction. Beyond that, the change of resistivity with the variation of fiber volume fraction becomes much flat. Another interest finding is that the resistivity of the cement materials is a function of frequency of applied voltage. The microstructure associated with the electrical properties of composite is observed. It is possible to apply cement/carbon fiber composite as an electromagnetic shielding composite and so on.

Flexural Toughness of Sprayable Strain-Hardening Cement Composite (SHCC) for Seismic Retrofit of Non-Ductile Reinforced Concrete Frames

2013 ◽  
Vol 658 ◽  
pp. 34-37 ◽  
Author(s):  
Seung Ju Han ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Strain Hardening ◽  
Strong Influence ◽  
Volume Fraction ◽  
Cement Composite ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Test ◽  
Concrete Frames ◽  
Flexural Toughness

This experimental study investigates the flexural behavior and toughness of sprayable strain-hardening cement composite (SHCC) developed to retrofit seismically reinforced concrete structures with non-ductile reinforcement details. Three SHCC mixtures with specified compressive strength of 50 MPa are mixed and tested. All SHCC mixes with different dosage and combination of admixtures such as superplasticizer and powder admixture were reinforced with 2.2 % polyvinyl alcohol (PVA) fibers at the volume fraction. This paper focuses on the flexural toughness based on the flexural test results for 100 x 100 x 400 mm prisms. The flexural toughness is evaluated in accordance with ASTM C 1018. The results indicated that less than 2.5 % dosage of hybrid superplasticizer and powder admixtures respectively provides excellent sprayability and flexural behavior of SHCC mixed in this study. A strong influence of hybrid superplasticizer and powder admixture on the flexural toughness of SHCC mixes was observed.

Damage Tolerance of Reinforced Concrete (RC) Beams with a Layer of PE Fiber Reinforced Strain-Hardening Cement Composite (PE-SHCC)

2013 ◽  
Vol 372 ◽  
pp. 219-222
Author(s):  
Yeon Jun Yun ◽  
Seok Joon Jang ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Rc Beam ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Cracking Behavior ◽  
Flexural Performance ◽  
Strength And Ductility

This work evaluated the applicability of polyethylene (PE) fiber reinforced strain-hardening cement composite (PE-SHCC) layer at the bottom of reinforced concrete (RC) beams to improve the flexural performance and cracking behavior. PE-SHCC material with specific compressive strength of 70MPa was reinforced with 1.5% PE fibers at the volume fraction. Four RC beams with cross-section of 130 x 170mm and length of 1,460mm were made and tested under four-point monotonic loading. Three beams were layered with PE-SHCC material and one whole RC beam was a control specimen for comparison. Principal variable is the thickness of PE-SHCC layer; 20, 40 and 60mm that are equivalent to 11, 23 and 35% of beams depth. Experimental results indicated that the addition of PE-SHCC layer enhanced the crack-damage mitigation of RC beams and improve the structural behavior, such as strength and ductility, of RC beams.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Effect of Fiber Volume Fraction on Behavior of Concrete Beams Made with Recycled Concrete Aggregates

2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda
Keyword(s):  
Fiber Volume Fraction ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Beam Specimen ◽  
Rc Beam ◽  
Fiber Volume ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.

Static Behavior of Layered Fiber Reinforced Concrete T-Shaped Beam

2010 ◽  
Vol 168-170 ◽  
pp. 2037-2043
Author(s):  
Yin Gu ◽  
Wei Dong Zhuo ◽  
Yu Ting Qiu
Keyword(s):  
Reinforced Concrete ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Parameter Analysis ◽  
Beam Specimen ◽  
Rc Beam ◽  
High Modulus ◽  
Fiber Reinforced ◽  
Initial Stiffness ◽  
Fiber Volume

This paper proposes a concept of layered fiber reinforced concrete (LFRC) beam. In the concept of a LFRC beam, low-modulus fiber and high-modulus fiber are randomly dispersed and uniformly distributed into the concrete matries of the compression and tension zones, respectively. The static behaviors of LFRC beam are investigated from both experimental and numerical aspects. Four-point bending tests are performed on two simply supported T-shaped LFRC beam specimens and an ordinary T-shaped RC beam specimen with large scales. Comparison between the testing results of LFRC and RC beam specimens shows that the initial cracking load, flexural toughness and post-yielding stiffness of a LFRC beam can be significantly improved, but the ultimate loads are nearly without change. Numerical simulations are also carried out to investigate the static behaviors of the LFRC beam specimens. It is found that the simulation results are agreed well with that of tests. Further numerical parameter analysis for the LFRC beam specimens is conducted. The effects of high-modulus fiber volume fraction on the static behaviors of LFRC beams are studied. The research results show that the additions of high-modulus fibers have little effect on the initial stiffness, yielding loads and ultimate loads of LFRC beams; both the load and displacement at the initial cracking point increase linearly with the increasing volume fraction of the high-modulus fiber, but both the yielding displacement and ultimate displacement decrease linearly with the increasing volume fraction of the high-modulus fiber.

Performance of Bamboo Fiber Reinforced Composites: Mechanical Properties

2021 ◽  
Vol 879 ◽  
pp. 284-293
Author(s):  
Norliana Bakar ◽  
Siew Choo Chin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Vinyl Ester ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Bamboo Fiber ◽  
Synthetic Fiber ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Volume Fractions

Fiber Reinforced Polymer (FRP) made from synthetic fiber had been widely used for strengthening of reinforced concrete (RC) structures in the past decades. Due to its high cost, detrimental to the environment and human health, natural fiber composites becoming the current alternatives towards a green and environmental friendly material. This paper presents an investigation on the mechanical properties of bamboo fiber reinforced composite (BFRC) with different types of resins. The BFRC specimens were prepared by hand lay-up method using epoxy and vinyl-ester resins. Bamboo fiber volume fractions, 30%, 35%, 40%, 45% and 50% was experimentally investigated by conducting tensile and flexural test, respectively. Results showed that the tensile and flexural strength of bamboo fiber reinforced epoxy composite (BFREC) was 63.2% greater than the bamboo fiber reinforced vinyl-ester composite (BFRVC). It was found that 45% of bamboo fiber volume fraction on BFREC exhibited the highest tensile strength compared to other BFRECs. Meanwhile, 40% bamboo fiber volume fraction of BFRVC showed the highest tensile strength between bamboo fiber volume fractions for BFRC using vinyl-ester resin. Studies showed that epoxy-based BFRC exhibited excellent results compared to the vinyl-ester-based composite. Further studies are required on using BFRC epoxy-based composite in various structural applications and strengthening purposes.

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