scholarly journals A Study of the Flexural Behavior of Fiber-Reinforced Concretes Exposed to Moderate Temperatures

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3522
Author(s):  
Marta Caballero-Jorna ◽  
Marta Roig-Flores ◽  
Pedro Serna
Keyword(s):  
Steel Fiber ◽  
Flexural Behavior ◽  
Polypropylene Fibers ◽  
Fiber Reinforced ◽  
Insulation System ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Three Point Bending ◽  
Lower Performance ◽  
Cracked Specimens

The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C.

Investigation of tensile and flexural behavior of biaxial and rib 1 × 1 weft-knitted composite using experimental tests and multi-scale finite element modeling

2019 ◽  
Vol 53 (23) ◽  
pp. 3201-3215 ◽  
Author(s):  
Reza Hessami ◽  
Aliasghar Alamdar Yazdi ◽  
Abbas Mazidi
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Experimental Results ◽  
Flexural Behavior ◽  
Bending Tests ◽  
Three Point Bending ◽  
Element Modeling ◽  
Multi Scale ◽  
Scale Modeling ◽  
Composite Samples

In this study, tensile and flexural behavior of biaxial and rib weft-knitted composite is obtained numerically and experimentally. Multi-scale finite element modeling is employed to simulate the tensile and flexural behavior of composite samples. In the finite element modeling, the geometry of a unit cell of each fabric is initially modeled in ABAQUS software, and then periodic boundary conditions were applied to a unit cell. The stiffness matrix for each structure was obtained by a python code via meso scale modeling and used as input data for the macro modeling. To validate the numerical model, two types of weft-knitted fabrics (rib 1 × 1 and biaxial fabrics) are produced by a flat weft knitting machine. Epoxy resin is used to construct composite by the vacuum injection process (VIP). After that, the tensile and three-point bending tests were applied to composite samples. The experimental results showed that tensile strength and tensile modulus of biaxial composites are greater than rib composites, in both wale and course directions. Moreover, in three-point bending test, biaxial composite showed more strength and more stiffness in comparison to rib composite. Finite element results were compared to experimental results in tensile and bending tests. The results showed that good agreement with experimental results in the linear section of tensile and flexural behavior of composites. Consequently, the current multi-scale modeling can be used to predict the stiffness matrix and mechanical behavior of complex composite structures such as knitted composites.

J Integral of Steel Fiber Reinforced High Strength Concrete

2012 ◽  
Vol 476-478 ◽  
pp. 1568-1571
Author(s):  
Ting Yi Zhang ◽  
Guang He Zheng ◽  
Ping Wang ◽  
Kai Zhang ◽  
Huai Sen Cai
Keyword(s):  
High Strength Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Three Point Bending ◽  
Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.

scholarly journals Flexural Behavior of Fiber Reinforced Self-Compacting Rubberized Concrete Beams

2020 ◽  
Vol 26 (2) ◽  
pp. 111-128
Author(s):  
Tamara M. Hasan ◽  
Ahmed S. Ali
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Monotonic Loading ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Repeated Loading ◽  
Fiber Reinforced ◽  
Waste Tire

The massive growth of the automotive industry and the development of vehicles use lead to produce a huge amount of waste tire rubber. Rubber tires are non-biodegradable, resulting in environmental problems such as fire risks. In this search, the flexural behavior of steel fiber reinforced self-compacting concrete (SFRSCC) beams containing different percentages and sizes of waste tire rubbers were studied and compared them with the flexural behavior of SCC and SFRSCC. Micro steel fiber (straight type) with aspect ratio 65 was used in mixes. The replacement of coarse and fine aggregate was 20% and 10% with chip and crumb rubber. Also, the replacement of limestone dust and silica fume was 50%, 25%, and 12% with ground rubber and very fine rubber, respectively. Twelve beams with small-scale (L=1100mm, h = 150mm, b =100mm) were tested under two points loading (monotonic loading). Fresh properties, hardened properties, load-deflection relation, first crack load, ultimate load, and crack width were investigated. Two tested reinforced concrete beams from experimental work were selected as a case study to compare with the results from ABAQUS program (monotonic loading). These two reinforced concrete beams were simulated as a parametric study under repeated loading using this finite element program. The results showed that the flexural behavior of SFRSCC beams containing rubber was acceptable when compared with flexural behavior of SCC and SFRSCC beams (depended on load carrying capacity). Cracks width was decreased with the addition of steel fibers and waste tires rubber.  An acceptable agreement can be shown between the results of numerical analysis and the results obtained from experimental test (monotonic loading). Insignificant ultimate load differences between the results of monotonic loading and repeated loading                                                                                                                                                                                           

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