Composite Fibers in Concretes with Various Strengths

Mačanovskis, Artūrs; Lukašenoks, Artūrs; Krasņikovs, Andrejs; Stonys, Rimvydas; Lūsis, Vitālijs

doi:10.14359/51702343

Cited by 13 publications

(8 citation statements)

References 5 publications

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“…Another factor is fiber declination angle to the direction of the pull-out force. Observations showed that the current value of the pull-out force decreases proportionally to the size of the crack opening; all these factors are confirmed, for example, by the following studies [42][43][44].…”

Section: Mechanical 4pbt Resultssupporting

confidence: 60%

Experimental Investigation and Modelling of the Layered Concrete with Different Concentration of Short Fibers in the Layers

Lūsis

Kononova

Mačanovskis

et al. 2021

Fibers

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The use of steel fiber reinforced concrete (SFRC) in structures with high physical-mechanical characteristics allows engineers to reduce the weight and costs of the structures, to simplify the technology of their production, to reduce or completely eliminate the manual labor needed for reinforcement, at the same time increasing reliability and durability. Commonly accepted technology is exploiting randomly distributed in the concrete volume fibers with random each fiber orientation. In structural members subjected to bending, major loads are bearing fibers located close to outer member surfaces. The majority of fibers are slightly loaded. The aim of the present research is to create an SFRC construction with non-homogeneously distributed fibers. We prepared layered SFRC prismatic specimens. Each layer had different amount of short fibers. Specimens were tested by four point bending till the rupture. Material fracture process was modelled based on the single fiber pull-out test results. Modelling results were compared with the experimental curves for beams. Predictions generated by the model were validated by 4PBT of 100 × 100 × 400 mm prisms. Investigation had shown higher load-bearing capacity of layered concrete plates comparing with plate having homogeneously distributed the same amount of fibers. This mechanism is strongly dependent on fiber concentration. A high amount of fibers is leading to new failure mechanisms—pull-out of FRC blocks and decrease of load-bearing capacity. Fracture surface analysis was realized for broken prisms with the goal to analyze fracture process and to improve accuracy of the elaborated model. The general conclusion with regard to modelling results is that the agreement with experimental data is good, numeric modelling results successfully align with the experimental data. Modelling has indicated the existence of additional failure processes besides simple fiber pull-out, which could be expected when fiber concentration exceeds the critical value.

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Section: Mechanical 4pbt Resultssupporting

confidence: 60%

Experimental Investigation and Modelling of the Layered Concrete with Different Concentration of Short Fibers in the Layers

Lūsis

Kononova

Mačanovskis

et al. 2021

Fibers

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“…The pull-out of the fibers from the concrete matrix of the samples was the main micromechanical mechanism of load bearing at the post-cracking stage. For concretes with PP and ARG fibers as well as PP and CF fiber-reinforced concretes, the fiber pull-out process occurred simultaneously with the partial splitting of most macro-fibers bridging the macrocrack, with simultaneous partial micro-fibers rupture in the bundles, which correlated well with the results of studies by other authors [42][43][44]. The samples with glass fibers were tough and brittle.…”

Section: Discussionsupporting

confidence: 86%

Concrete Reinforced by Hybrid Mix of Short Fibers under Bending

Lūsis

Annamaneni

Krasņikovs

2022

Fibers

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In the present study, the mechanical behavior of Fiber-Reinforced Concrete (FRC) beams was studied under bending until rupture. Each beam was reinforced with a hybrid mix of short fibers randomly distributed in its volume. Concrete beams with three different fiber combinations were investigated, namely, beams reinforced with (1) a homogeneously distributed mix of short polypropylene fibers (PP) and steel fibers, (2) PP fibers and Alkali Resistant Glass (ARG) fibers, and (3) PP and composite fibers (CF). The amount of short PP fibers was the same in all FRCs. The investigation focused on the fracture mechanisms and the load-bearing capacity of FRC beams with the developing macro cracks. In total, 12 FRC composite prismatic specimens were casted and tested in four-point bending experiments (4PBT). The current load value versus the Crack Mouth Opening Displacement (CMOD) for all FRCs was analyzed. The crack opening relationship and the influence of fibers on the fracture energy and flexural tensile strength were determined. Rupture surfaces of all samples were investigated using an optical microscope.

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“…In the past, one of the main engineering challenges was the development, introduction, and mass production of efficient materials in all industrial areas. Different fiberreinforcement options are used in various fields [1][2][3][4][5], including the use of various materials and technologies [6][7][8][9]. Due to its superior physical characteristics, such as low density, thermal constancy, high strength, and modulus of elasticity, polyacrylonitrile (PAN) is a commercially important semicrystalline polymer [10,11].…”

Section: Introductionmentioning

confidence: 99%

Testing the Physical and Mechanical Properties of Polyacrylonitrile Nanofibers Reinforced with Succinite and Silicon Dioxide Nanoparticles

et al. 2022

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In this research, we focused on testing the physical and mechanical properties of the developed polyacrylonitrile (PAN) composite nanofibers with succinite (Baltic amber) and SiO2 particles using standard methods of nanofiber testing (physical and mechanical properties). Polyacrylonitrile composite nanofibers (based on the electrospinning method) were coated on an aluminum substrate for structural investigation. SEM was used to determine the average fiber diameter and standard deviation. The mechanical properties of the fibers were determined using a universal testing machine (NANO, MTS). We observed that constant or decreased levels of crystallinity in the ultrafine composite nanofibers led to the preservation of high levels of strain at failure and that the strength of nanofibers increased substantially as their diameter reduced. Improvements in PAN composite nanofibers with succinite and SiO2 nanopowder are feasible with continuous decreases in diameter. The drastically decreased strain at failure demonstrated a substantial reduction in viscosity (toughness) of the annealed nanofibers. Large stresses at failure in the as-spun nanofibers were a result of their low crystallinity. As a result, decreasing the diameter of PAN nanofibers from approximately 2 micrometers to 139 nanometers (the smallest nanofiber tested) resulted in instantaneous increases in the elastic modulus from 1 to 26 GPa, true strength from 100 to 1750 MPa, and toughness from 20 to 604 MPa.

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Composite Fibers in Concretes with Various Strengths

Cited by 13 publications

References 5 publications

Experimental Investigation and Modelling of the Layered Concrete with Different Concentration of Short Fibers in the Layers

Experimental Investigation and Modelling of the Layered Concrete with Different Concentration of Short Fibers in the Layers

Concrete Reinforced by Hybrid Mix of Short Fibers under Bending

Testing the Physical and Mechanical Properties of Polyacrylonitrile Nanofibers Reinforced with Succinite and Silicon Dioxide Nanoparticles

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