Mecanismo De Fissuraçao Sob Tração Direta De Compósitos Cimentícios Reforçados Com Fibras Curtas De Sisal

Lima, Paulo Roberto Lopes; Filho, Romildo Dias Tolêdo; Lima, José Mário Feitosa

doi:10.22409/engevista.v15i1.363

Cited by 6 publications

(7 citation statements)

References 8 publications

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“…The binder was composed of 30% of Portland cement CP-32 F II, 30% of metakaolin and 40% of fly ash. The use of such a high content of metakaolin and fly ash aims to guarantee the durability of the sisal fiber, as shown in previous research [15]. The presence of fly ash is aimed also to ensure a greater workability to the matrix allowing a better fiber dispersion [16].…”

Section: Methodsmentioning

confidence: 99%

Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites

Ferreira

Lima²,

Silva

et al. 2014

KEM

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Cycles of wetting and drying can change the microstructure of vegetable fibers through a mechanism known as hornification, which modifies the polymeric structure of the fiber-cells resulting in a higher dimensional stability. In the present work the influence of hornification on the sisal fiber-matrix bond adhesion as well as in the sisal fiber dimensional stability and mechanical behaviour under direct tension was evaluated. Furthermore, cementitious composites reinforced with randomly dispersed hornified sisal fibers were developed and characterized under bending loads. The results show that the tensile strength and strain at failure of the hornified sisal fibers were increased by about 5% and 39%, respectively, whereas the modulus of elasticity was reduced by 9%. The fibers also presented higher dimensional stability with the hornification process. The fiber-matrix bonding was improved and the pull-out resistance of the fibers submitted to ten cycles of wetting and drying was increased by about 40% to 50%. The higher fiber-matrix bond strength contributed to an increase in the ductility and post-cracking behaviour of the composite. The fracture process was characterized by the formation of multiple cracks with the hornified sisal fibers presenting a higher ability to bridge and arrest the cracks.

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Section: Methodsmentioning

confidence: 99%

Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites

Ferreira

Lima²,

Silva

et al. 2014

KEM

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“…For the creation of the cementitious matrix, metakaolin and fly ash were used -the specific mass being 2.37 kg/dm 3 and 2.28 kg/dm 3 , respectively. The use of pozzolans in cementitious matrices causes the consumption of calcium hydroxide, thereby avoiding fiber mineralization [11].…”

Section: Methodsmentioning

confidence: 99%

Effect of Treatment of Sisal Fiber on Morphology, Mechanical Properties and Fiber-Cement Bond Strength

Santos

Lima

2014

KEM

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The dimensional instability of vegetable fibers due to hygroscopicity results in a gradual loss of adherence in cement based composites which, when in service, are submitted to a natural variation of humidity. Such an effect reduces the contribution of the fiber as a reinforcement and can cause the early rupture of the material. In this work, a treatment of the sisal fibers is performed with the applying of wetting-drying cycles in order to alter their crystalline structure and improve the dimensional stability of the fiber to withstand the variation of humidity: 6, 10, 20, 30 and 34 cycles were applied in order to evaluate the effect on the properties of fiber; a tensile test, the morphological characterization (MEV) and the evaluation of the chemical structure of fiber were carried out. The effect of the treatment on fiber-matrix behavior was evaluated using the pull-out test. Embedded lengths of 16, 20, 30, 40 and 44 mm were defined through a factorial design and used in the test. It is verified that the use of 10 wetting-drying cycles causes less damage to the tensile strength and the elastic modulus of the fiber and contributes to a better adherence with the matrix, with an increase of up to 23 % compared with the untreated fiber. The statistical analysis of the interaction effect between the studied factors, using 2K factorial design with central composite design, indicates that the number of cycles can be decreased when using a longer length of the embedded fiber.Keywords: wetting-drying cycles, pull out test, tensile strength..

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“…A aplicação de fibras vegetais, como sisal e coco, para reforçar matrizes frágeis à base de cimento é uma técnica que foi amplamente empregada na década de 70, na fabricação de placas planas e corrugadas para elementos de cobertura em países em desenvolvimento (COUTTS, 1988). No inicio dos anos 80, a utilização de fibras vegetais como reforço de compósitos a base de cimento foi bruscamente interrompida depois que alguns elementos construtivos apresentaram perda de resistência após poucos meses de aplicação (LIMA et al, 2013). Após a análise dos mecanismos de deterioração da fibra vegetal em meio alcalino (GRAM, 1983) e a proposição de soluções para assegurar compósitos duráveis (TOLEDO FILHO et al, 2003;LIMA e TOLEDO FILHO, 2008), que coincidiram com a preocupação 18 mundial com a sustentabilidade, o emprego deste tipo de fibra como reforço de compósitos à base de cimento voltou a despertar interesse científico.…”

Section: Brazilian Journal Ofunclassified

Evaluation of the durability of cementicious composites reinforced with natural vegetable fibers from the Amazon

De Oliveira,

Melo Filho

2024

Braz. J. Develop.

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The study of the use of plant fibers as reinforcement for cementitious composites has become increasingly common in recent years, thanks to the advancement of technologies and the demand for innovative and sustainable materials. In the Amazon, this resource is widely found and used for different applications, and the present work is interested in evaluating the use of these fibers as structural reinforcement of cement slabs. The mechanical and durability properties of cementitious composites reinforced with a content of 5% vegetable fibers from jute (Corchorus capsularis) and mallow (Urena lobata L.) were investigated. The objective was to evaluate the quality and performance of these fibers as reinforcement of cementitious plates for a possible use of these composites in Civil Construction. Spreading and thermogravimetry tests were carried out on the matrix and tensile tests in flexion at 4 points on the composites. The results obtained indicated that the fibers provided an increase in the flexural strength and toughness of the composites, as well as the use of metakaolinite as a pozzolanic material, contributed to increasing the durability of these composites, indicating a great possibility of using them in structural and semi-structural applications.

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Mecanismo De Fissuraçao Sob Tração Direta De Compósitos Cimentícios Reforçados Com Fibras Curtas De Sisal

Cited by 6 publications

References 8 publications

Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites

Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites

Effect of Treatment of Sisal Fiber on Morphology, Mechanical Properties and Fiber-Cement Bond Strength

Evaluation of the durability of cementicious composites reinforced with natural vegetable fibers from the Amazon

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