Influence of Stress Level and Fibre Volume Fraction on Fatigue Performance of Glass Fibre-Reinforced Polyester Composites

Zaghloul, Mahmoud Yousry Mahmoud; Zaghloul, Moustafa Mahmoud Yousry; Zaghloul, Mai Mahmoud Yousry

doi:10.3390/polym14132662

Cited by 66 publications

(42 citation statements)

References 68 publications

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“…Furthermore, the analysis of the mechanical properties over time is of great importance since GFRPs are usually heavily used in constructional applications [66][67][68][69][70][71][72][73]. Among these studies, only a few investigated the environmental aging-induced deterioration of the mechanical properties of the same R-GFRPs [69,72].…”

Section: Discussionmentioning

confidence: 99%

Influence of Environmental Parameters and Fiber Orientation on Dissolution Kinetics of Glass Fibers in Polymer Composites

et al. 2022

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Glass fibers slowly dissolve and age when exposed to water molecules. This phenomenon also occurs when glass fibers are inside fiber-reinforced composites protected by the matrix. This environmental aging results in the deterioration of the mechanical properties of the composite. In structural applications, GFRPs are continuously exposed to water environments for decades (typically, the design lifetime is around 25 years or even more). During their lifetime, these materials are affected by various temperatures, pH (acidity) levels, mechanical loads, and the synergy of these factors. The rate of the degradation process depends on the nature of the glass, sizing, fiber orientation, and environmental factors such as acidity, temperature, and mechanical stress. In this work, the degradation of typical industrial-grade R-glass fibers inside an epoxy fiber-reinforced composite was studied experimentally and computationally. A Dissolving Cylinder Zero-Order Kinetic (DCZOK) model was applied and could describe the long-term dissolution of glass composites, considering the influence of fiber orientation (hoop vs. transverse), pH (1.7, 4.0, 5.7, 7.0, and 10.0), and temperature (20, 40, 60, and 80 °C). The limitations of the DCZOK model and the effects of sizing protection, the accumulation of degradation products inside the composite, and water availability were investigated. Dissolution was experimentally measured using ICP-MS. As in the case of the fibers, for GFRPs, the temperature showed an Arrhenius-type influence on the kinetics, increasing the rate of dissolution exponentially with increasing temperature. Similar to fibers, GFRPs showed a hyperbolic dependence on pH. The model was able to capture all of these effects, and the limitations were addressed. The significance of the study is the contribution to a better understanding of mass loss and dissolution modeling in GFRPs, which is linked to the deterioration of the mechanical properties of GFRPs. This link should be further investigated experimentally and computationally.

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Section: Discussionmentioning

confidence: 99%

Influence of Environmental Parameters and Fiber Orientation on Dissolution Kinetics of Glass Fibers in Polymer Composites

et al. 2022

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“…However, the existing literature somehow neglected the fatigue properties of PC as a repair material of pavement [ 26 ]. Zaghloul, et al [ 27 , 28 ] found both the stress level and the fiber content have a great influence on the tensile and fatigue behaviors of fiber-reinforced polyester. Yeon, et al [ 29 ] and Ahn, et al [ 30 ] investigated the fatigue performance of PC and its stiffness damage through bending beam tests and vibration measurements, but mainly focused on the effects of test methods on the fatigue characteristics of PC.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Properties and Its Prediction of Polymer Concrete for the Repair of Asphalt Pavements

Ren

2022

Polymers

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Polymer concrete (PC) is considered a promising repair material for asphalt pavement, since it has excellent paving performance and water stability. Although the mechanical properties of PC have been widely researched, the fatigue behavior of PC under traffic loads was still poorly understood. To predict the fatigue life and optimize the material design of PC, the semi-circular bending (SCB) tests were performed, considering different polymer content, sand ratio, aggregate features and stress condition. Two typical polymer materials were applied to prepare PC specimens, including epoxy resin (ER) and polyurethane (PU). The aggregate features were analyzed by the aggregate image measurement system. The mechanical behavior under repeated loads was investigated by the displacement, fatigue life and stiffness modulus. Results show that the flexural strength increases nonlinearly with the increasing polymer content, rapidly at first, and then slowly. The optimized polymer content and sand ratio were respectively 15% and 30%. As the loading number increases, the vertical displacement of PC shows three stages, i.e., undamaged stage, damage development stage, and fatigue failure stage. The stiffness modulus of the specimen is stress-dependent. An empirical model was developed to predict the fatigue life of PC, which can effectively capture the effects of the polymer content, sand ratio and stress level (or nominal stress ratio). It suggests that the fatigue life has a strong correlation with the mixing gradation, and the optimal sand ratio of PC can be determined by the proposed function. Moreover, the effect of aggregate shapes cannot be neglected.

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“…The addition of polypropylene fibers can optimize the pore size distribution of concrete and improve the crack resistance of concrete [ 14 ] and adding basalt fibers to concrete can improve the permeability, carbonation resistance, acid and alkali corrosion resistance, frost resistance and high temperature resistance of the structures [ 15 ]. Zaghloul et al [ 21 ] studied the effect of fiber volume fraction and applied stress level on the fatigue life of composites, and proposed that fiber composites maintained a good initial strength retention rate after high-frequency fatigue cycles. Serrano et al [ 22 ] put forward by means of a fire test that adding 1% polypropylene fiber and 2% steel fiber could improve the compressive strength of concrete, polypropylene fiber concrete could reduce the tension in the concrete pores at an ambient temperature of 400 °C, thereby delaying the appearance of spalling and cracks on concrete and improving the fire resistance of concrete.…”

Section: Introductionmentioning

confidence: 99%

Flexural Toughness Test and Inversion Research on a Thermal Conductivity Formula on Steel Fiber-Reinforced Concrete Components Post-Fire

Chen

Zhu

et al. 2022

Materials

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Steel fibers are widely used because they can effectively improve the tensile, compressive and flexural properties of concrete structures. The selection of steel fiber dosage and aspect ratio at high temperature has an important impact on the flexural toughness of concrete components post-fire. In this paper, discussions are made on the simulated fire test in compliance with the ISO 834 standard to study the steel fiber-reinforced concrete (SFRC) components post-fire. The research reveals the influence of two commonly used steel fiber aspect ratios (50, 70) and steel fiber dosages (30 kg/m3, 40 kg/m3, 45 kg/m3) on the changes of the internal temperature field, the initial crack flexural strength and the flexural toughness of the SFRC components under a single-side fire. Moreover, combined with the four-point flexural test of the SFRC components post fire, the research also describes the damage of high temperatures to the flexural toughness of SFRC components, and suggests a calculation formula for SFRC thermal conductivity by way of the numerical inversion method. The results of this study have verified that the incorporation of steel fiber into concrete helps to reduce its internal thermal stress difference and improve the crack resistance and fire resistance of the concrete. Moreover, under high temperature conditions, the concrete component added with the steel fiber in an aspect ratio of 70 and a dosage of 45 kg/m3 increased their initial crack flexural strength by 56.8%, higher than that of plain concrete components, and the loss of equivalent flexural strength and flexural toughness of SFRC post fire was only 45.2% and 13.6%, respectively. The proposed calculation formula of thermal conductivity can provide a reference for a numerical simulation study of the temperature field of SFRC components in a high temperature environment.

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Influence of Stress Level and Fibre Volume Fraction on Fatigue Performance of Glass Fibre-Reinforced Polyester Composites

Cited by 66 publications

References 68 publications

Influence of Environmental Parameters and Fiber Orientation on Dissolution Kinetics of Glass Fibers in Polymer Composites

Influence of Environmental Parameters and Fiber Orientation on Dissolution Kinetics of Glass Fibers in Polymer Composites

Fatigue Properties and Its Prediction of Polymer Concrete for the Repair of Asphalt Pavements

Flexural Toughness Test and Inversion Research on a Thermal Conductivity Formula on Steel Fiber-Reinforced Concrete Components Post-Fire

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