Effect of Polypropylene Fibers on Self-Healing and Dynamic Modulus of Elasticity Recovery of Fiber Reinforced Concrete

El-Newihy, Adham; Azarsa, Pejman; Gupta, Rishi; Biparva, Alireza

doi:10.3390/fib6010009

Cited by 33 publications

(21 citation statements)

References 15 publications

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“…In the case of mixtures with fibers, the slump flow tests were not possible to execute because their workabilities were too low. The tests show that the workability of the mixtures was significantly deteriorated due to the addition of synthetic fibers as was observed in different research i.e., [ 61 ]. Because of the incorporation of the additional surface to cover, the consistency class decreased by three for FF_2, two for PM_3, PD_3 and PD_2, and one for PM_2 compared to PC.…”

Section: Methodsmentioning

confidence: 58%

Flexural Tensile Strength of Concrete with Synthetic Fibers

Blazy

Drobiec

Wolka³

2021

Materials

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Fiber reinforcement is currently most often used in floors, railway sleepers, prefabricated structural elements such as slabs, beams and tanks, and in small architecture elements. Designing elements or structures made of fiber-reinforced concrete requires knowledge of its basic mechanical parameters. In the case of concretes with metallic fibers, the literature can find many tests and standard guidelines regarding compressive, flexural, tensile strength and fracture energy. The properties of concretes with non-metallic fibers are slightly less recognized, especially concretes with new types of polymer fibers. Additionally, the lack of standardized methods of testing concrete with polymer fibers make their application much more difficult. In the article, the possibility of using the EN 14651 standard to assess the flexural tensile strength of concrete with the addition of 2.0 and 3.0 kg/m3 of synthetic fibers with different geometry and form was presented. There was a 5.5–13.5% increase in the flexural tensile strength depending on the mixture type. Moreover, in the case of fiber-reinforced concretes, the ductility was enhanced and the samples were characterized by significant residual flexural tensile strengths. Additionally, from the workability tests it was concluded that after the incorporation of fibers, the consistency class decreased by one, two or three. Nevertheless, the compressive strengths of concrete with and without fibers were very similar to each other, and varied from 58.05 to 61.31 MPa. Moreover, it was concluded that results obtained from three-point bending tests significantly differed from empirical formulas for the calculation of the flexural tensile strength of fiber-reinforced concretes with dispersed steel fibers present in the literature. As a result, the new formula determined by the authors was proposed for concrete with polymer fibers with a nominal fiber content ≤1.0% and slenderness of up to 200. It must be mentioned that the formula gave a very good agreement with studies presented in different literature positions. In addition, an attempt was made to evaluate the strengths of tested mixes in accordance with the Model Code 2010. However, it occurred that the proposed fiber-reinforced concrete mixtures would not be able to replace traditional reinforcement in a form of steel bars. Furthermore, in uniaxial tensile tests, it was not possible to determine the σ–w graphs, and received results for maximum tensile strength did not show the clear influence of fibers incorporation on concrete. Then, the fracture energy enhancement (from about 16 to 22 times) and dependencies: crack mouth opening displacement–deflection; crack mouth opening displacement–crack tip opening displacement; and crack tip opening displacement–deflection were analyzed. Finally, the results from flexural tensile tests were compared with measurements of the surface displacement field obtained through the Digital Image Correlation technique. It was concluded that this technique can be successfully used to determine the crack mouth and crack tip opening displacements with very high accuracy.

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Section: Methodsmentioning

confidence: 58%

Flexural Tensile Strength of Concrete with Synthetic Fibers

Blazy

Drobiec

Wolka³

2021

Materials

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“…Two commercially available polypropylene (PP) fibers were used for this research study. El-Newihy et al [41] describes them as Type A and B. The former type is a macro monofilament fiber with a patented sinusoidal deformation, while the latter is a 100% smooth virgin polypropylene micro fiber.…”

Section: Methodsmentioning

confidence: 99%

“…From the literature review, it was evident to the authors that the influence of fiber volume content, geometry, orientation, length, etc., on post-cracking and SH behavior of FRCC when cured under different regimes, is not well understood and is scarcely available in the literature. A recent study conducted by the authors [41] indicated that the inclusion of PP fiber in virgin concrete resulted in a higher SH ratio and higher dynamic modulus of elasticity. The enhancement was detected by a resonance frequency testing method, but several knowledge gaps remained.…”

Section: Novelty Of the Studymentioning

confidence: 97%

Self-Healing Potential and Post-Cracking Tensile Behavior of Polypropylene Fiber-Reinforced Cementitious Composites

2021

Self Cite

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The use of synthetic fibers as reinforcement in fiber-reinforced cementitious composites (FRCC) demonstrates a combination of better ductile response vis-à-vis metallic ones, enhanced durability in a high pH environment, and resistance to corrosion as well as self-healing capabilities. This study explores the effect of macro- and micro-scale polypropylene (PP) fibers on post-crack energy, ductility, and the self-healing potential of FRCC. Laboratory results indicate a significant change in fracture response, i.e., loss in ductility as curing time increases. PP fiber samples cured for 2 days demonstrated ductile fracture behavior, controllable crack growth during tensile testing, post-cracking behavior, and a regain in strength owing to FRCC’s self-healing mechanism. Different mixes of FRCC suggest an economical mixing methodology, where the strong bond between the PP fibers and cementitious matrix plays a key role in improving the tensile strength of the mortar. Additionally, the micro PP fiber samples demonstrate resistance to micro-crack propagation, observed as an increase in peak load value and shape deformation during compression and tensile tests. Notably, low volume fraction of macro-scale PP fibers in FRCC revealed higher post-crack energy than the higher dosage of micro-scale PP fibers. Lastly, few samples with a crack of < 0.5 mm exhibited a self-healing mechanism, and upon testing, the healed specimens illustrated higher strain values.

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“…There was no possibility of a visual analysis of the cracks and their sealing, since the specimens would be compromised, and the readings of the ultrasound pulse velocity would not be continued. Therefore, the authors recommend future studies containing ultrasonic test and image analysis in parallel, with more specimens and using a cracking method that would allow standardization and identification of the exact location of the cracks, such as those applied by Gupta and Biparva [27] and El-Newihy et al [28]. and drying cycle, again being related to the availability of anhydrate particles in the early ages.…”

Section: Effect Of Cracking Induction Age On Concrete Self-healingmentioning

confidence: 99%

Monitoring the Self-healing of Concrete from the Ultrasonic Pulse Velocity

et al. 2019

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Concrete has the ability to naturally heal its cracks, in a process called self-healing. This article aimed to analyze the self-healing of concretes, evaluating the influence of fly ash and the age of occurrence of cracks. Concrete specimens were submitted to cracking at 7 and 28 days. Subsequently, the samples were exposed to 12 wetting and drying cycles in order to favor the self-healing process. The phenomenon was evaluated through the ultrasonic pulse velocity testing, performed weekly on the specimens from the molding stage until the end of all cycles. The concretes showed a decrease in ultrasonic pulse velocity at the time they were cracked. This is due to the greater difficulty in the propagation of ultrasonic waves in the voids formed during cracking. This drop was higher for concrete with fly ash. Also, the results show that the fly ash concretes presented a more expressive self-healing process when cracked at 28 days, which may be related to the presence of pozzolanic reactions and the presence of more anhydrous particles. The concretes without fly ash had self-healing when they were cracked at 7 days. This is explained by the high hydration rate characteristic of ordinary Portland cement.

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Effect of Polypropylene Fibers on Self-Healing and Dynamic Modulus of Elasticity Recovery of Fiber Reinforced Concrete

Cited by 33 publications

References 15 publications

Flexural Tensile Strength of Concrete with Synthetic Fibers

Flexural Tensile Strength of Concrete with Synthetic Fibers

Self-Healing Potential and Post-Cracking Tensile Behavior of Polypropylene Fiber-Reinforced Cementitious Composites

Monitoring the Self-healing of Concrete from the Ultrasonic Pulse Velocity

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