Effect of Alkali Treatment to Improve Fiber-Matrix Bonding and Mechanical Behavior of Sisal Fiber Reinforced Cementitious Composites

Castoldi, Raylane de Souza; Souza, Lourdes Maria Silva de; Silva, Flávio de A.

doi:10.1007/978-3-030-83719-8_5

Cited by 2 publications

(12 citation statements)

References 26 publications

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“…The untreated fibers showed slightly higher values in scale parameter and Weibull average, with diminished standard deviations found for the 10.0‐wt% NaOH‐treated fibers. Similar results were also reported in previous studies, 17–33 occurring because of an increase in cellulose to lignin ratios, making the fibers less stiff, which will be further addressed through XRD and TGA evaluations.…”

Section: Resultssupporting

confidence: 88%

“…The rupture of the alkali-treated fibers, as also evidenced in previous studies, 15,31 was partially related to a demand for higher loads for proper debonding in the frictional bond period, this being higher than the fiber tensile strength, leading to the fiber rupturing and incomplete pullout. Additionally, increases in bond strength can also be found to increase fiber roughness, through the removal of hemicellulose and lignin by alkali treatment, where the cellulose depolymerizes and the fiber fibrillation occurs, increasing the surface roughness of the fiber.…”

Section: Pullout Testingsupporting

confidence: 60%

“…Additionally, increases in bond strength can also be found to increase fiber roughness, through the removal of hemicellulose and lignin by alkali treatment, where the cellulose depolymerizes and the fiber fibrillation occurs, increasing the surface roughness of the fiber. 31 The pullout energy also presents insight related to the composite ductility at a macro level, where untreated fibers showed increased energy when pulled out, therefore aiming at a composite higher energy dissipation, as evidenced in tensile and flexural tests.…”

Section: Pullout Testingmentioning

confidence: 99%

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The influence of alkaline treatment on the mechanical performance of geopolymer composites reinforced with Brazilian malva and curaua fibers

2022

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Lignocellulosic fibers obtained from the curaua (Ananas erectifolius) and malva (Malva sylvestris) plants in Brazil can be used as suitable reinforcements for geopolymers (GPs) owing to their high strength, ready regional availability, and low cost. In this work, the tensile and flexural strengths of untreated and NaOH alkali‐treated curaua and malva fiber‐reinforced GP composites were measured according to ASTM standards. Curaua reinforced GP composites had an average tensile strength of 25.7 (±) 7.1 MPa and flexural strength of 18.9 (±) 4.72 MPa. Malva GP composites withstood 19.18 (±) 9.0 MPa in tension and 31.5 (±) 7.6 MPa in flexure. Additionally, pullout tests were performed to investigate the debonding mechanisms for both fibers, with and without alkaline treatment, finding increases in chemical bonding for the treated samples due to roughness enhancements through fiber surface modifications with alkali treatment. Thermogravimetric analysis and X‐ray diffraction were used to characterize the physical fiber modifications after alkali treatment, evidencing lignin and hemicellulose removals. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy were used to further examine the fiber–matrix interaction, with proofs of interfacial tailoring.

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Section: Resultssupporting

confidence: 88%

Section: Pullout Testingsupporting

confidence: 60%

Section: Pullout Testingmentioning

confidence: 99%

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The influence of alkaline treatment on the mechanical performance of geopolymer composites reinforced with Brazilian malva and curaua fibers

2022

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“…Generally, specific fly ash is used as the matrix for the production of GPs [48]. High-dose pozzolanic materials can also be used in matrix production, and the cementing materials are Portland cement, fly ash, and metakaolin to obtain a low-alkaline GP matrix [81]. Dawood et al [65] used a local ceramic powder and slag in their study.…”

Section: Precursormentioning

confidence: 99%

“…Sometimes the properties of composites are adjusted by adding nanomaterials [82][83][84]. Castoldi et al [81] took river sand as the fine aggregate for a GP, and its maximum particle size was controlled within 4.75 mm, and its fineness modulus was 3.02. The maximum diameter of the coarse aggregate used in GPs was 12.5 mm.…”

Section: Aggregatementioning

confidence: 99%

A Review of Sisal Fiber-Reinforced Geopolymers: Preparation, Microstructure, and Mechanical Properties

Qu,

Niu,

et al. 2024

Molecules

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The early strength of geopolymers (GPs) and their composites is higher, and the hardening speed is faster than that of ordinary cementitious materials. Due to their wide source of raw materials, low energy consumption in the production process, and lower emissions of pollutants, they are considered to have the most potential to replace ordinary Portland cement. However, similar to other inorganic materials, the GPs themselves have weak flexural and tensile strength and are sensitive to micro-cracks. Improving the toughness of GP materials can be achieved by adding an appropriate amount of fiber materials into the matrix. The use of discrete staple fibers shows great potential in improving the toughness of GPs. Sisal is a natural fiber that is reproducible and easy to obtain. Due to its good mechanical properties, low cost, and low carbon energy usage, sisal fiber (SF) is a GP composite reinforcement with potential development. In this paper, the research progress on the effect of SF on the properties of GP composites in recent decades is reviewed. It mainly includes the chemical composition and physical properties of SFs, the preparation technology of sisal-reinforced geopolymers (SFRGs), the microstructure analysis of the interface of SFs and the GP matrix, and the macroscopic mechanical properties of SFRGs. The properties of SFs make them have good bonding properties with the GP matrix. The addition of SFs can improve the flexural strength and tensile strength of GP composites, and SFRGs have good engineering application prospects.

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Effect of Alkali Treatment to Improve Fiber-Matrix Bonding and Mechanical Behavior of Sisal Fiber Reinforced Cementitious Composites

Cited by 2 publications

References 26 publications

The influence of alkaline treatment on the mechanical performance of geopolymer composites reinforced with Brazilian malva and curaua fibers

The influence of alkaline treatment on the mechanical performance of geopolymer composites reinforced with Brazilian malva and curaua fibers

A Review of Sisal Fiber-Reinforced Geopolymers: Preparation, Microstructure, and Mechanical Properties

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