scholarly journals A More Realistic Study on the Mechanical Properties of CFRC Composite Grouting Material under a Long-Term Water Immersion Process

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yao Xiao ◽  
Huafeng Deng ◽  
Jianlin Li ◽  
Eleyas Assefa
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Immersion ◽  
Fiber Content ◽  
Grouting Material ◽  
Bonding Properties ◽  
Grouting Materials ◽  
Dam Foundations

The long-term effect of water immersion on the mechanical properties of CFRC composite grouting materials was studied by using five different carbon fiber contents (0, 0.25%, 0.50%, 0.75%, and 1.00%). The direct shear and long-term immersion tests were performed based on the specified and optimum values of carbon fiber content, respectively. The results showed the following: (1) the application of carbon fiber significantly improved the shear resistance of CRFC composite grouting material by using “reinforcing” and “anchoring” actions. The shear strength of the specimen was increasing by 5.66%∼43.41% when the carbon fiber content increased from 0.25% to 1.00%. After a comprehensive analysis, the optimum carbon fiber content was found to be 0.75%. (2) The degradation in the compressive and tensile strength of CRFC composite specimens exhibited a consistent trend (i.e., a steep gradient was gradually followed by a gentle slope) under a long-term water immersion process. About 90% of the total degradation in the compressive and tensile strength has occurred in 90 immersion days (i.e., 16.05% and 18.45%, respectively). In comparison, the degradation in the tensile strength (20.05%) was slightly higher than the compressive strength (18.16%). (3) Under the long-term water immersion process: the properties of the specimens were gradually deteriorating, the carbon fibers were gradually reaching a fatigue stage, and the bonding properties of carbon fiber was decreasing, which resulted in a reduction in the compressive and tensile strength. The uniaxial compression failure mode changed from brittle to ductile, and the development of local failure was very noticeable. Based on the findings of this paper, groundwater has a significant impact on the mechanical properties of grouted rock mass such as dam foundations and abutments. Therefore, the degradation in the grouting materials has to be considered in practical cases.

Durability study of pultruded carbon fiber reinforced polymer plates subjected to water immersion

2017 ◽  
Vol 21 (4) ◽  
pp. 571-579 ◽  
Author(s):  
Bin Hong ◽  
Guijun Xian ◽  
Zike Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Water Immersion ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Resin Matrix ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

Pultruded carbon fiber reinforced polymer plates have been widely used for structural rehabilitation due to their excellent mechanical properties. Even though, the long-term durability performance of carbon fiber reinforced polymer plates is still a concern, especially when subjected to harsh environmental conditions (e.g. water immersion). In the present study, the effects of water immersion at 23°C, 40°C, and 60°C on the degradation of the pultruded carbon fiber reinforced polymer plates were investigated in terms of water uptake and mechanical properties. To elucidate the degradation mechanisms, the resin matrix and the fiber and resin adhesion were also assessed in the same conditions. The test results indicated that water immersion, especially at higher temperatures, leads to serious fiber debonding, and thus the carbon fiber reinforced polymer samples absorb much more water than the resin matrix. In addition, the transverse flexural strength of the carbon fiber reinforced polymer plates, closely correlated to the fiber–resin adhesion, reduced significantly at high temperatures. On the contrary, the resin matrix and carbon fiber reinforced polymer plates show much less degradation subjected to the same immersion conditions. Therefore, to comprehensively understand the long-term durability of a carbon fiber reinforced polymer material, it is necessary to test the variation of the bonding strength between fiber and resin matrix, in addition to the tensile performances in fiber directions of the carbon fiber reinforced polymer plates.

scholarly journals Absorption and Strength Properties of Short Carbon Fiber Reinforced Mortar Composite

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Absorption ◽  
Carbon Fibers ◽  
Strength Properties ◽  
Fiber Content ◽  
Test Results ◽  
Air Content ◽  
Entrapped Air ◽  
Short Carbon

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.

Effects of Accelerated Aging Period of Time at 180°C on Tensile Property of Plain Woven Fabric/Epoxy Resin Laminated Composites

2012 ◽  
Vol 182-183 ◽  
pp. 76-79 ◽  
Author(s):  
Lei Lei Song ◽  
Quan Rong Liu ◽  
Jia Lu Li
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Laminated Composites ◽  
Accelerated Aging ◽  
Woven Fabric ◽  
Accelerated Ageing ◽  
Time Intervals ◽  
Composite Samples

In this paper, carbon fiber reinforced resin matrix composites were produced by stacking eight pieces of carbon fiber woven plain fabric and subjected to accelerated ageing. Accelerated ageing was carried out in oven at 180°C for three different time intervals (60 hours, 120 hours and 180 hours). The influence of different ageing time intervals at 180°C on tensile properties of laminated composites was examined, compared with the composites without aging. The appearance and damage forms of these laminated composites were investigated. The results revealed that the tensile strength of the laminates declined significantly after long term accelerated aging at 180°C. The average tensile strengths of composite samples aged 60 hours, 120 hours, and 180 hours period of time at 180°C are 80.36%, 79.82%, 76.57% of average tensile strength of composite samples without aging, respectively. The high temperature accelerated aging makes the resin macromolecular structure in the composites changed, and then the adhesive force between fiber bundles and resin declines rapidly which result in the tensile strength of composites aged decrease. This research provides a useful reference for long term durability of laminated/epoxy resin composites.

scholarly journals The Influence of Sample Preparation on the Strength Results ofa Pan-based Carbon Fiber

2010 ◽  
Vol 4 (4) ◽  
pp. 329-337
Author(s):  
Fabio Pereira ◽  
◽  
Fabiana Vieira ◽  
Luiz de Castro ◽  
Ricardo Michel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Sample Preparation ◽  
Young’S Modulus ◽  
Carbon Fibers ◽  
Weibull Modulus ◽  
Strong Influence ◽  
Mechanical Tests ◽  
Preparation Process

In this work the influence of different configurations in the sample preparation process on commercial polyacrylonitrile-based carbon fibers mechanical tests were studied. Mechanical properties, such as tensile strength, Young’s modulus, elongation and Weibull modulus, were evaluated. The results showed that all sample preparation steps may have strong influence on the results.

A Study on Mechanical Properties of Short Carbon Fiber Reinforced Polycarbonate via an Injection Molding Process

2020 ◽  
Vol 18 (11) ◽  
pp. 801-805
Author(s):  
Kyung-Soo Jeon ◽  
R. Nirmala ◽  
Seong-Hwa Hong ◽  
Yong-II Chung ◽  
R. Navamathavan ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Testing Machine ◽  
Fiber Content ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Short Carbon Fiber ◽  
Short Carbon

This manuscript is dealt with the synthesis of short carbon fibers reinforced polycarbonate polymer composite by using injection modeling technique. Four different composite materials were obtained by varying the carbon fibers weight percentage of 10, 20, 30 and 40%. The synthesized carbon fibers/polycarbonate composites were characterized for their morphological, mechanical and thermal properties by means of scanning electron microscopy (SEM), universal testing machine (UTM) and IZOD strength test. The resultant carbon fibers/polycarbonate composites exhibited excellent interfacial adhesion between carbon fibers and polycarbonate resin. The tensile properties were observed to be monotonically increases with increasing carbon fiber content in the composite resin. The tensile strength of carbon fiber/polycarbonate composites with the carbon fiber content 40% were increased about 8 times than that of the pristine polycarbonate matrix. The carbon fibers/polycarbonate composites with 40 wt.% of short carbon fibers exhibited a high tensile strength and thermal conductivity. The incorporation of carbon fiber in to polycarbonate resin resulted in a significant enhancement in the mechanical and the thermal behavior. These studies suggested that the short carbon fiber incorporated polycarbonate composite matrix is a good candidate material for many technological applications.

scholarly journals Thermal and Mechanical properties of epoxy-jute fiber composite

2014 ◽  
Vol 27 (2) ◽  
pp. 77-82 ◽  
Author(s):  
H Ahmad ◽  
MA Islam ◽  
MF Uddin
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Fiber Length ◽  
Epoxy Composite ◽  
Fiber Composite ◽  
Young Modulus ◽  
Fiber Content ◽  
Jute Fiber ◽  
Elongation At Break

Chopped jute fiber-epoxy composites with varying fiber length (2-12 mm) and mass fraction (0.05-0.35) had been prepared by a heat press unit. The cross-linked product was characterized in terms of specific gravity, thermal conductivity, tensile strength, Young modulus and elongation at break. The transverse thermal conductivities for randomly oriented fibers in the composite were investigated by Lees and Charlton’s method. The tensile strength, Young modulus and elongation at break were investigated by a Universal Tensile Tester. With an increase in the fiber content (irrespective of the fiber length), the thermal conductivity of the composite decreases; the decreasing rate being highest for the fiber length of 2 mm followed by that for the fiber length of 6 and 12 mm. The decreasing rate of the thermal conductivity of the jute-epoxy composite is comparatively higher to that reported in literature for acrylic polymer hemp fiber composite. The tensile strength also decreases with the increase of the fiber content in the composite. The fiber length does not show to have significant effect on the tensile strength of the composite; the variation in strength being masked within experimental error. The Young modulus increases with the increase of fiber content within elastic limit; showing the highest values for the fiber length of 6 mm followed by those for the fiber length of 2 mm and 12 mm. The elongation at break shows slightly increasing trend up to 15% fiber content, but beyond that it decreases drastically. The specific gravity decreases with the increase in the fiber content and thus the recalculated specific tensile strength is found to keep at a stable level of 36MPa up to the fiber content of 20%, and beyond that the specific tensile strength decreases with the increase in the fiber content. It is concluded that jute fiber-epoxy composite could be used as a good heat-insulating material. Further investigation is recommended on the improvement of the thermal insulation keeping the mechanical properties unchanged or even improved. The TGA study is also required to ascertain the field of application of the material. DOI: http://dx.doi.org/10.3329/jce.v27i2.17807 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 2, December 2012: 77-82

scholarly journals Experimental Investigation on Mechanical Properties of In Situ Cemented Paste Backfill Containing Coal Gangue and Fly Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinguo Zhang ◽  
Shichuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Friction Angle ◽  
Coal Gangue ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill containing coal gangue and fly ash (CGFACPB) is an emerging backfill technique for coal mines that allows environmentally hazardous coal gangue and fly ash to be reused in the underground goaf. Meanwhile, CGFACPB can provide an efficient ground support and reduce the surface subsidence. Due to the difference of consolidation environment between the laboratory and the field, the mechanical properties of the cemented paste backfill vary significantly. In this paper, the core specimens were collected from an underground coal mine where the CGFACPB was used for coal mining, and the mechanical properties of the collected specimens were investigated. The cores were obtained from the underground coal mine, and then the standard cylinders or discs were prepared in laboratory. The uniaxial compressive strength (UCS), Young’s modulus, and Poisson’s ratio were determined by the compression tests, and the tensile strength was achieved by the Brazilian test. Then the internal friction angle and cohesion were calculated using the improved Mohr–Coulomb strength criterion. The results showed the development of UCS can be divided into four stages, and the final long-term stable value was about 5.1 MPa. The development of Young’s modulus had similar trend. Young’s modulus had a range from 550 MPa to 750 MPa and the mean value of 675 MPa. Poisson’s ratio gradually increased with the underground curing duration and eventually approached the stable value of 0.18. The failure type of compression samples was mainly single-sided shear failure. The development of tensile strength can be divided into two stages, and the stable value of the tensile strength was about 1.05 MPa. The development of cohesion can be divided into four stages, and the stable value was about 1.75 MPa. The stable value of the internal friction angle was about 25°. This study can provide significant references for not only the long-term stability evaluation of CGFACPB in the field but also the design of optimal recipe of the cemented paste backfill (CPB).

Preparation of Environment-Friendly Composite from Waste Paper Fiber and Waste Collagen

2011 ◽  
Vol 71-78 ◽  
pp. 2978-2982
Author(s):  
Yin Fei Tan ◽  
Bin Liu ◽  
Peng Fei Li ◽  
Ming Bo Gu ◽  
Li Juan Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Material ◽  
Elastic Modulus ◽  
Fiber Content ◽  
Waste Paper ◽  
Environment Friendly

Waste newspaper fiber was filled in the collagen cross-linked by glutaraldehyde. The effects of deinking fiber, glycerol dosage, glutaraldehyde dosage on the mechanical properties of composite were investigated. It is found that the deinking treatment increases the strength of the composite material. The composite has better mechanical properties under the preparing conditions as follows: waste newspaper fiber content 10%, glutaraldehyde dosage12.5%, glycerol dosage 12.5%, pH 9.7, 60°C for 2h. The tensile strength and elastic modulus are 4.98Mpa and 0.09Gpa, respectively.

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