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

Author(s):  
John K. Makunza ◽  
G. Senthil Kumaran

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.

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay

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.


2021 ◽  
Vol 879 ◽  
pp. 284-293
Author(s):  
Norliana Bakar ◽  
Siew Choo Chin

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.


2014 ◽  
Vol 915-916 ◽  
pp. 784-787
Author(s):  
Yan Lv

Based on the mechanical properties experiment of the glass fiber reinforced concrete with 0%0.6%0.8% and 1% glass fiber volume fraction, the mechanics property such as tensile strength, compressive strength, flexural strength and flexural elasticity modulus are analyzed and compared with the plain concrete when the kinds of fiber content changes. The research results show that the effect of tensile strength and flexural strength can be improved to some extent, which also can serve as a reference or basis for further improvement and development the theory and application of the glass fiber reinforced concrete.


2019 ◽  
Vol 28 (4) ◽  
pp. 273-284
Author(s):  
Jai Inder Preet Singh ◽  
Sehijpal Singh ◽  
Vikas Dhawan

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.


2016 ◽  
Vol 2 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hasan Jalilifar ◽  
Fatholla Sajedi ◽  
Sadegh Kazemi

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.


2020 ◽  
Vol 8 (6) ◽  
pp. 5393-5397

In the present era, Natural fibers are favored for the formation of composites due to their low density, high strength, biodegradability, easy production, low carbon foot, environment friendly nature in comparison of synthetic fibers. This Paper deals with NFRC made from natural fibers obtained from the plants of arid region of Western Rajasthan on which a few researchers are focusing. This paper discuss on the extraction process of fiber from the ber’s stems, manufacturing of composites by using epoxy resin & ber’s fibers then testing of its mechanical properties e.g. tensile strength, young modulus, yield strength , and percentage elongation. Six Sample were made having weight ratio - 0.1, 0.2, 0.3, 0.4, 0.45, & 0. 6. Dog bone samples were prepared according to the ASTM D638 (Type IV) standard. Tensile strength varies from 12.19 MPa to 25 MPa, while young modulus varies from 1.4GPa to 2.9GPa for different weight ratios. Yield strength varies from 10.77 MPa to 21.16 MPa. Percentage of Elongation varies from 1 to 3%. These results shows that ber’s stems can be used for fiber extraction to manufacture composites materials & for better mechanical properties minimum fiber volume fraction percentage is 13% and maximum fiber fraction is 31%.This data can be used further when optimum value of fiber volume fraction is required to form composites from ber’s fibers.


2021 ◽  
Vol 1016 ◽  
pp. 151-155
Author(s):  
Keizo Hashimoto ◽  
Jiang Jin

Although metal matrix composites (MMC) for the high temperature structural material have been investigated extensively for many years, applications of MMC have been still limited. Among many combinations between the ceramic fibers and the matrix materials, combination of SiC fiber and TiAl based intermetallic compounds has been expected to be one of the best combination, since both SiC fiber and TiAl have demonstrated the capabilities of the low density heat resistant materials. SiC fiber reinforced TiAl composites have been successfully fabricated using hot press method. Optimum temperature and pressure have been determined. SiC/TiAl composite having relatively low fiber volume fraction shows nearly an ideal elastic property applying the law of mixture. Effects of interface layers on the mechanical properties of composites have been studied in detail. Micro-indentation on a single fiber was carried out to examine the pull out strength of SiC fiber quantitatively. Estimated shear stress on the interface was 145-195MPa, those values are quite reasonable since the tensile strength of TiAl matrix was 420MPa and the maximum shear stress would be the half of tensile strength according to Schmid law. Three-point bending tests have been carried out to evaluate the mechanical properties of composites. Fiber volume fraction 8.9% specimen shows ideal bending stiffness compare with the calculated values based on the low of mixture. Reaction layers and the interface between SiC fiber and TiAl have been analyzed by SEM-EDS and XRD. At least two or more reaction layers have been identified. These reaction layers can be explained based on the Si-Ti-C ternary equilibrium phase diagram at 1373K. Optimum conditions of interface structure will be discussed


2021 ◽  
pp. 004051752110648
Author(s):  
Mengmeng Zhou ◽  
Gaoming Jiang ◽  
Zhe Gao

Weft-knitted biaxial tubular (WKBT) fabrics have been infiltrated via a resin film infusion technique to fabricate reinforced composites. To understand the mechanical properties of WKBT fabrics and the reinforced composites, the strength efficiency of insertion yarns and insertion fiber volume fraction are used to evaluate the tensile strength. The tensile properties of WKBT fabrics and the reinforced composites are studied in the 0° and 90° directions. The results show that both have two failure stages. The first stage is the fracture of insertion yarns which provide the main tensile strength, and the second stage is the fracture of stitch yarns which have significant effect on the tensile strength of WKBT fabrics and the reinforced composites. It is observed that the deformation behavior and failure mechanism of WKBT fabric reinforced composites are closely related to the structure of WKBT fabric, which can be used to predict the failure mode and morphology of WKBT fabric reinforced composites.


2015 ◽  
Vol 799-800 ◽  
pp. 794-799 ◽  
Author(s):  
Sebti Jaballi ◽  
Imed Miraoui ◽  
Hedi Hassis

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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