Optimization of Flexural Strength and Thermal Conductivity of Mortar Reinforced with Alfa Fibers

This paper focuses on the optimization of flexural strength and thermal conductivity of mortar reinforced with Alfa fibers. Fibers were manually extracted from Alfa leafs to avoid the risk of degradation of mechanical properties. A first group of samples (300 x 300 x 30 mm) having a fiber volume fraction of 0.5 to 1.5% is prepared to measure the thermal conductivity.The second composite family (40 x 40 x 160 mm) cured in a wet chamber is used for measuring its bending strength. The fiber percentage varies from 0.74 to 1,85%.The results show that the thermal conductivity decreases by increasing the fiber content. While the optimal percentage of fiber for the flexural strength is estimated at 1%, corresponding to an increase of 27% in strength.

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Investigation on the Mechanical Properties of Fiber Reinforced Recycled Concrete

Civil Engineering Journal ◽

10.28991/cej-2016-00000009 ◽

2016 ◽

Vol 2 (1) ◽

pp. 13-22 ◽

Cited By ~ 3

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.

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

Journal of Composite Materials ◽

10.1177/00219983211004706 ◽

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.

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Influence of fiber volume fraction and curing temperature on mechanical properties of jute/PLA green composites

Polymers and Polymer Composites ◽

10.1177/0967391119872875 ◽

2019 ◽

Vol 28 (4) ◽

pp. 273-284

Author(s):

Jai Inder Preet Singh ◽

Sehijpal Singh ◽

Vikas Dhawan

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Fiber Volume Fraction ◽

Natural Fiber ◽

Volume Fraction ◽

Matrix Material ◽

Research Work ◽

Curing Temperature ◽

Green Composites ◽

Fiber Volume

Rising environmental concerns and depletion of petrochemical resources have resulted in an increased interest in biodegradable natural fiber-reinforced polymer composites. In this research work, jute fiber has been used as a reinforcement and polylactic acid (PLA) as the matrix material to develop jute/PLA green composites with the help of compression molding technique. The effect of fiber volume fraction ranging from 25% to 50% and curing temperature ranging from 160°C to 180°C on different samples were investigated for mechanical properties and water absorption. Results obtained from various tests indicate that with an increase in the fiber volume fraction, tensile and flexural strength increases till 30% fiber fraction, thereafter decreases with further increase in fiber content. Maximum tensile and flexural strength of jute/PLA composites was obtained with 30% fiber volume fraction at 160°C curing temperature. The trend obtained from mechanical properties is further justified through the study of surface morphology using scanning electron microscopy.

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Peningkatan Sifat Mekanik Komposit Serat Alam Limbah Sabut Kelapa (Cocofiber) yang Biodegradable

Reka Buana Jurnal Ilmiah Teknik Sipil dan Teknik Kimia ◽

10.33366/rekabuana.v6i1.2257 ◽

2021 ◽

Vol 6 (1) ◽

pp. 30-37

Author(s):

Sri Hastuti ◽

Herru Santosa Budiono ◽

Diki Ilham Ivadiyanto ◽

Muhammad Nurdin Nahar

Keyword(s):

Mechanical Properties ◽

Fiber Volume Fraction ◽

Bending Strength ◽

Natural Fiber ◽

Volume Fraction ◽

Fiber Composites ◽

Coconut Fiber ◽

Fiber Volume ◽

Coconut Coir ◽

The Impact

Inovasi baru serat dari sabut kelapa dimanfaatkan untuk meningkatkan nilai ekonomis dari serat sabut kelapa, oleh karena itu dirancanglah pendayagunaan serat dari sabut kelapa untuk penguat komposit dengan material serat alam yang biodegradable. Hal ini untuk mendukung penggunaan komposit yang ramah terhadap lingkungan dan mengurangi penggunaan material komposit serat sintetis yang polutan. Tujuan penelitian adalah menganalisis sifat mekanik pada komposit serat alam bermaterial serat dari sabut kelapa yang ramah lingkungan. Metode penelitian pembuatan komposit berpenguat serat dari sabut kelapa dilakukan treatment NaOH 15% selama 5 jam dan fraksi volume serat 10 %, 15 %, dan 20 %. Komposit serat dari sabut kelapa dengan matriks UPRs 157 BQTN dengan hardener MEXPO. Pengujian mekanik dilakukan uji bending menggunakan standar ASTM D790 dan uji impak menggunakan standar ASTM D5941. Pengujian impak komposit serat alam menunjukkan ketangguhan impak komposit pada fraksi volume serat 20% dengan nilai 0.017588J/mm2. Hasil pengujian menunjukkan peningkatan fraksi volume serta berpengaruh terhadap peningkatan kekuatan bending komposit serat dari sabut kelapa dengan kekuatan optimum bending pada fraksi volume serat 10% dengan nilai 44,33N/mm2. Hal ini menunjukkan peningkatan fraksi volume serat dengan perendaman NaOH 15% akan meningkatkan sifat mekanik bending dan impak komposit. Perendaman NaOH memberikan pengaruh daya serap sabut kelapa terhadap matrik Unsaturated Polyester yang dapat meningkatkan daya rekat antara penguat serat dengan matrik sehingga meningkatkan sifat mekanik bending dan impak komposit. ABSTRACT The innovation of coco fiber is used to increase the economic value of coconut coir, therefore the utilization of coconut fiber for reinforcing composites with biodegradable natural fiber material is designed. This is to support the use of composites that are friendly to the environment and reduce the use of pollutant synthetic fiber composite materials. The research objective was to analyze the mechanical properties of natural fiber composites with environmentally friendly coconut fiber as material. The research method of making fiber-reinforced composites from coconut coir was carried out by 15% NaOH treatment for 5 hours and a fiber volume fraction of 10%, 15%, and 20%. Composite fiber from coconut coir with UPRs 157 BQTN matrix with MEXPO hardener. Mechanical testing is carried out using the ASTM D790 standard and the impact test using the ASTM D5941 standard. The impact test of natural fiber composites showed the impact toughness of the composite at a fiber volume fraction of 20% with a value of 0.017588 J/ mm2. The test results showed an increase in volume fraction and an effect on the increase in the bending strength of coconut fiber composites with the optimum bending strength at a fiber volume fraction of 10% with a value of 44.33N /mm2. This shows that the increase in fiber volume fraction by immersion in 15% NaOH will increase the bending mechanical properties and the impact of the composite. Soaking NaOH has an effect on the absorption power of coconut coir on the Unsaturated Polyester matrix which can increase the adhesion between the fiber reinforcement and the matrix thereby increasing the bending mechanical properties and impact of the composite.

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Evaluating the effect of variable fiber content on mechanical properties of additively manufactured continuous carbon fiber composites

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684420963217 ◽

2020 ◽

pp. 073168442096321

Author(s):

Dakota R Hetrick ◽

Seyed Hamid Reza Sanei ◽

Charles E Bakis ◽

Omar Ashour

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

Fiber Volume Fraction ◽

Volume Fraction ◽

Fiber Content ◽

Fiber Volume ◽

Transverse Strength ◽

Continuous Carbon Fiber ◽

3D Printed ◽

Properties Of Composites

Fiber volume fraction is a driving factor in mechanical properties of composites. Micromechanical models are typically used to predict the effective properties of composites with different fiber volume fractions. Since the microstructure of 3D-printed composites is intrinsically different than conventional composites, such predictions need to be evaluated for 3D-printed composites. This investigation evaluates the ability of the Voigt, Reuss, and Halpin–Tsai models to capture the dependence of modulus and strength of 3D-printed composites on varying fiber volume fraction. Tensile coupons were printed with continuous carbon fiber-reinforced Onyx matrix using a Markforged Mark Two printer. Specimens were printed at five different volume fractions with unidirectional fibers oriented at either [Formula: see text] to obtain longitudinal, shear, and transverse properties, respectively. It is shown that the Voigt model provides an excellent fit for the longitudinal tensile strength and a reasonable fit for the longitudinal modulus with varied fiber content. For the transverse direction, while the Reuss model fails to capture the transverse modulus trend, the Halpin–Tsai model provides a reasonable fit as it incorporates more experimental parameters. Like conventional composites, addition of fibers degrades the transverse strength, and the transverse strength decreases with increasing fiber volume fraction. The shear modulus variation with fiber content could not be fitted reasonably with either Halpin–Tsai model or Reuss model.

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Effects of Fiber Content and Water Ratio on the Strength of Fiber Reinforced Mortar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.3961 ◽

2012 ◽

Vol 204-208 ◽

pp. 3961-3964

Author(s):

Yao Wang ◽

Wei Hong Xuan ◽

Yu Zhi Chen ◽

Xiao Hong Chen ◽

Gang Zheng

Keyword(s):

Flexural Strength ◽

Fiber Volume Fraction ◽

Volume Fraction ◽

Polypropylene Fiber ◽

Fiber Content ◽

Early Age ◽

Fiber Reinforced ◽

Fiber Volume ◽

Cement Material ◽

Water Ratio

The compressive and flexural strength of ordinary mortar and fiber reinforced mortar with five different pp fiber content were tested in this paper. The results show that the compressive strength reduced gradually with PP fiber increasing, and the flexural strength increased when the fiber volume fraction is no more than 0.12%. The higher water ratio can weaken the cohesiveness of the fiber and cement material, and the influence of polypropylene fiber on the flexural strength of mortar decreased after soaking. The major strength damage in the process of curing is caused in the early age and appropriate amount of fiber is beneficial to reduce strength damage.

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An Experimental Investigation on Suitability of Using Sisal Fibers in Reinforced Concrete Composites

10.4028/www.scientific.net/cta.1.24 ◽

2022 ◽

Author(s):

John K. Makunza ◽

G. Senthil Kumaran

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Reinforced Concrete ◽

Flexural Strength ◽

Fiber Volume Fraction ◽

Volume Fraction ◽

Interfacial Bond ◽

Interfacial Bond Strength ◽

Fiber Volume ◽

Sisal Fibers

Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of concrete such as compressive and tensile strengths. Concrete is strong in compression but weak in tension and is a brittle material. In the construction industry, strength, durability and cost are among the major factors for selecting the suitable construction materials. During this investigation, the mechanical properties of sisal fibers reinforced concrete (SFRC) were assessed namely, flexural strength, tensile strength ad interfacial bond strength. The said properties were assessed in two types of reinforcement namely, randomly oriented sisal fibers and parallel oriented sisal fibers reinforcement. In both cases the sisal fibers were varied in volume fractions so as to establish the optimum value. The mechanical properties of flexural and tensile strengths were found to increase considerably with increasing fiber volume fractions until an optimum volume fraction is reached, thereafter, the strengths were found to decrease continuously. The prominent increment of 32.4% in flexural strength at fiber volume fraction of 2.0% parallel reinforced fiber concrete composite was observed. There was very small increment on both flexural and tensile strength for randomly oriented chopped sisal fibers reinforced concrete (SFRC). The Interfacial bond strength was found to be 0.12 N/mm2 and was observed to be prominent for chopped sisal fibers reinforced concrete specimens tested for flexural strength. During failure, fiber pull-out was observed and the composite was observed to behave in a ductile manner whereby the fibers were able to carry more load while full fracture had occurred on the specimen. The water absorption capacity of the SFRC was found to increase with increasing sisal fiber volume fraction.

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Performance of Bamboo Fiber Reinforced Composites: Mechanical Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.879.284 ◽

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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