scholarly journals Preparation of Nano-SiO2/Carbon Fiber-Reinforced Concrete and Its Influence on the Performance of Oil Well Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yanming Li ◽  
Xiaoyang Guo ◽  
Junlan Yang ◽  
Ming Li
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Reinforced Concrete ◽  
Cement Stone ◽  
Oil Well ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Oil Well Cement ◽  
Carbon Fiber Reinforced ◽  
Well Cement

In view of the oilfield well thin oil layer, small gap, and side drilling cementing after perforating and subsequent stimulation caused by the cement ring embrittlement (i.e., secondary channeling), the preparation of nano-SiO2/carbon fiber-reinforced body and its influence on the performance of oil well cement were studied to improve the cement stone and enhance its adaptability to oil well pressure in this study. Carbon fibers were treated by liquid phase oxidation and a coupling agent, and the “grafting to” was used to bond nano-SiO2 and carbon fibers. It was found that the mechanical properties of the enhanced cement stone are far better than those of the blank cement stone. The compressive strength and tensile strength of the enhanced oil well cement stone were increased by 25% and 26%, respectively, compared with those of the blank oil well cement sample; the modulus of elasticity was reduced by 29%. Finally, the enhancement mechanism of SiO2/carbon fiber reinforcement on cement stone was explored by infrared, scanning electron microscopy, and XRD patterns. The deflection effect, pull-out effect, and bridging effect of crack were obtained.

scholarly journals Effects of the Longitudinal Surface Roughness on Fiber Pull-Out Behavior in Carbon Fiber-Reinforced Epoxy Resin Composites

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Yin Yao ◽  
Shaohua Chen
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Fiber Reinforced ◽  
Fiber Stress ◽  
Pull Out ◽  
Carbon Fiber Reinforced

Surface modifications are known as efficient technologies for advanced carbon fibers to achieve significant improvement of interface adhesion in composites, one of which is to increase the surface roughness in the fiber's longitudinal direction in practice. As a result, many microridges and grooves are produced on carbon fiber's surfaces. How does the surface roughness influence the carbon fiber's pull-out behavior? Are there any restrictions on the relation between the aspect ratio and surface roughness of fibers in order to obtain an optimal interface? Considering the real morphology on carbon fiber's surface, i.e., longitudinal roughness, an improved shear-lag theoretical model is developed in this paper in order to investigate the interface characteristics and fiber pull-out for carbon fiber-reinforced thermosetting epoxy resin (brittle) composites. Closed-form solutions to the carbon fiber stress are obtained as well as the analytical load-displacement relation during pullout, and the apparent interfacial shear strength (IFSS). It is found that the interfacial adhesion and the apparent IFSS are effectively strengthened and improved due to the surface roughness of carbon fibers. Under a given tensile load, an increasing roughness will result in a decreasing fiber stress in the debonded zone and a decreasing debonded length. Furthermore, it is interesting to find that, for a determined surface roughness, an optimal aspect ratio, about 30∼45, of carbon fibers exists, at which the apparent IFSS could achieve the maximum. Comparison to the existing experiments shows that the theoretical model is feasible and reasonable to predict the experimental results, and the theoretical results should have an instructive significance for practical designs of carbon/epoxy composites.

scholarly journals Hybrid Effect of Wollastonite Fiber and Carbon Fiber on the Mechanical Properties of Oil Well Cement Pastes

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianglin Zhu ◽  
Jiangxiong Wei ◽  
Qijun Yu ◽  
Mingbiao Xu ◽  
Yuwei Luo
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Carbon Fiber ◽  
Impact Strength ◽  
Flexural Strength ◽  
Cement Stone ◽  
Oil Well ◽  
Cement Slurry ◽  
Oil Well Cement ◽  
Well Cement

Oil well cement is a type of natural brittle material that cannot be used directly in cementing operations. Fiber is a type of material that can effectively improve the strength and toughness of cement stone, and hybrid fiber materials can more effectively improve the performance of a cement sample. To overcome the natural defects of oil well cement, the new mineral fiber, i.e., wollastonite fiber, and common carbon fiber were used in oil well cement, and the micromorphology, mechanical properties, and stress-strain behavior of the cement were evaluated. The experimental results show that carbon fiber and wollastonite fiber are randomly distributed in the cement paste. The mechanical properties of the cement paste are improved by bridging and pulling out. The compressive strength, flexural strength, and impact strength of cement stone containing only carbon fiber or wollastonite fiber are higher than those of the pure cement, but too many fibers are not conducive to the development of mechanical properties. A mixture of 0.3% carbon fiber with 6% wollastonite fiber in oil well cement slurry results in a greater increase in compressive strength, flexural strength, and impact strength. In addition, compared with blank cement stone, the strain of the mixed cement stone increases substantially, and the elastic modulus decreases by 37.8%. The experimental results supply technical support for the design of a high-performance cement slurry system.

scholarly journals Static and Dynamic Performances of Chopped Carbon-Fiber-Reinforced Mortar and Concrete Incorporated with Disparate Lengths

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 972
Author(s):  
Yeou-Fong Li ◽  
Kun-Fang Lee ◽  
Gobinathan Kadagathur Ramanathan ◽  
Ta-Wui Cheng ◽  
Chih-Hong Huang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Blast Wave ◽  
Carbon Fibers ◽  
Impact Test ◽  
Free Fall ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced ◽  
The Impact

The impact load, such as seismic and shock wave, sometimes causes severe damage to the reinforced concrete structures. This study utilized different lengths of chopped carbon fibers to develop a carbon-fiber-reinforced mortar (CFRM) and carbon-fiber-reinforced concrete (CFRC) with high impact and anti-shockwave resistance. The different lengths (6, 12, and 24 mm) of chopped carbon fibers were pneumatically dispersed and uniformly mixed into the cement with a 1% weight proportion. Then the CFRM and CFRC specimens were made for static and dynamic tests. The compressive and flexural strengths of the specimens were determined by using the standard ASTM C39/C 39M and ASTM C 293-02, respectively. Meanwhile, a free-fall impact test was done according to ACI 544.2R-89, which was used to test the impact resistances of the specimens under different impact energies. The CFRM and CFRC with a length of 6 mm exhibit maximum compressive strength. Both flexural and free-fall impact test results show that the 24 mm CFRM and CFRC enhances their maximum flexural strength and impact numbers more than the other lengths of CFRM, CFRC, and the benchmark specimens. After impact tests, the failure specimens were observed in a high-resolution optical microscope, to identify whether the failure mode is slippage or rupture of the carbon fiber. Finally, a blast wave explosion test was conducted to verify that the blast wave resistance of the 24 mm CFRC specimen was better than the 12 mm CFRC and benchmark specimens.

scholarly journals Impact Response of Carbon Fiber Reinforced Concrete

2020 ◽  
Vol 8 (6) ◽  
pp. 5171-5175
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Impact Loading ◽  
Modulus Of Elasticity ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Fibre Reinforced Concrete ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced

Fiber reinforced concrete is becoming increasingly more important in the construction field due to its numerous applications and advantages. Fibre reinforced concrete (FRC) is composed of fibres and matrix. Fibres constitute the reinforcements and the main source of strength while the matrix ‘glues’ all the fibres together in shape and transfers the stress between the reinforcing fibres. Different types of fibres in use are steel, glass, carbon, basalt and aramid. Fibre reinforced concrete has many advantages such as improvement in the mechanical properties like modulus of elasticity, deflection, energy absorption and crack resistance. This paper discusses the experimental investigations carried out on carbon fiber reinforced concrete under impact loading. Mix design is carried out for M25 grade of concrete reinforced with carbon fibers in proportions of 0%, 0.75%, 1.00% and 1.25% by volume fraction. The test results show that there is an increase in compressive, split tensile and flexural strengths of carbon fiber reinforced concrete (not discussed in this paper). The inclusion of 1% carbon fibers showed the maximum enhancement in strength and it can be considered as optimum dosage. When compared to conventional concrete, the crack width also reduced in carbon fiber reinforced concrete. Extensometer test was conducted to determine the modulus of elasticity of concrete. The main aim of this study is to understand the dynamic behavior of carbon fiber reinforced concrete under impact loading. For carrying out the drop-weight tests, eight slab specimens were casted. The edges of the slab were fixed on all four sides. FRC slab with 1% addition of carbon fibres gave the best results. There was a decrease in displacement and an increase in impact energy for an the aspect ratio of fiber is 45.

scholarly journals Effect of Super Plasticizers on Fresh and Hardened State Properties of Short Carbon Fiber Reinforced Electrically Conductive Concrete

2020 ◽  
Vol 8 (5) ◽  
pp. 2644-2650
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Strength Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Electrically Conductive ◽  
Negative Effect ◽  
Hardened State ◽  
Carbon Fiber Reinforced ◽  
The Impact

This study enlightens the influence of superplasticizers (SP) on the dispersion and distribution of carbon fibers in the carbon fiber reinforced concrete (CFRC) cast with a low w/c ratio. The effectiveness of Polycarboxylate ether (PCE) based SP in the enhancement of workability of concrete and deagglomeration of carbon fibers in CFRC has been studied extensively in this study. The effect of PCE based SP on the compressive strength properties and electrical properties of the CFRC were also studied. The microstructure of the CFRC specimens was also analyzed to study the impact of SP on the deagglomeration of carbon fibers in CFRC. It was observed that the inclusion of carbon fibers in the dry concrete mixes without SP showed a negative effect on the functional properties of concrete whereas the inclusion of SP in the CFRC mixes improved the mobility and viscosity of the CFRC mixes. The fresh and hardened state properties were effectively enhanced with the use of SP in the CFRC mixes. The magnitude of decrease in electrical resistance was better in SP based CFRC resulting in more electrical conductivity. The microstructure of the CFRC indicated improvement in the distribution of carbon fibers in SP based CFRC.

Graphene oxide modified carbon fiber reinforced epoxy composites

2020 ◽  
Vol 40 (5) ◽  
pp. 415-420 ◽  
Author(s):  
Yasin Altin ◽  
Hazal Yilmaz ◽  
Omer Faruk Unsal ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Graphene Oxide ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Spray Coating ◽  
Sem Analysis ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Quick Method ◽  
Carbon Fiber Reinforced

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.

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