scholarly journals Effects of Defects on Bond Behavior of Fiber Reinforced Cementitious Matrix Materials

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 164 ◽  
Author(s):  
Antonio Bilotta ◽  
Gian Piero Lignola
Keyword(s):  
High Strength ◽  
Epoxy Adhesive ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
The Matrix ◽  
Low Sensitivity ◽  
Strengthening Technique ◽  
Geometrical Defects ◽  
Bond Tests

High-strength fibers embedded in inorganic matrix i.e., Fiber Reinforced Cementitious Mortar materials (FRCM) are commonly used as strengthening technique for existing masonry structures, due to the low sensitivity to debonding phenomena between substrate and matrix. Nevertheless, the use of lime or cement-based matrix instead of epoxy adhesive implies that attention has to be paid to the bond behavior between the fibers and the matrix, since sliding phenomena and cohesive failures in the mortar matrix can occur. The paper aims to investigate the effect of the mechanical properties of fiber and matrix on the FRCM efficiency, and potential geometrical defects, typical of real applications. The aim is to analyze the mechanical behavior of the FRCM system by simulating hypothetical bond tests, as they are usually performed in laboratories. The bond test has a significant role, as it is used for the qualification of the material, providing sometimes very scattered results. Hence, it is particularly important and greatly discussed in the scientific community and among manufactures and practitioners. The purpose is to understand where this variability could derive from and possibly how to contain it, to improve the characterization of FRCM systems. A mechanical model has been proposed to simulate the usual bond test to focus and stress the way in which each fiber slips out of the matrix as the load increases; and this has been recognized as the main reason for scattered results in bond tests. The model was then applied to the typical cases of PBO-FRCM and Glass-FRCM, hence considering different ratios for the fiber and matrix properties.

Experimental Analysis of the Bond Behavior of Glass, Carbon, and Steel FRCM Composites

2014 ◽  
Vol 624 ◽  
pp. 371-378 ◽  
Author(s):  
Tommaso D'Antino ◽  
Carlo Pellegrino ◽  
Christian Carloni ◽  
Lesley H. Sneed ◽  
Giorgio Giacomin
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Cementitious Matrix ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
The Matrix ◽  
Glass Carbon ◽  
Concrete Matrix

In recent decades, the construction industry has witnessed a rapid growth of interest in strengthening and retrofitting of existing reinforced concrete (RC) and masonry structures. Fiber reinforced polymer (FRP) composites have gained great popularity, and several studies are now available in the literature on their use in strengthening and retrofit applications. Promising newly-developed composite materials are represented by the so-called fiber reinforced cementitious matrix (FRCM) composites. FRCM composites are comprised of high strength fibers embedded within a cementitious matrix that is responsible for the stress transfer between the existing structure and the strengthening material. FRCM composites are still in their infancy, and very limited results are available in the literature on RC and masonry strengthening applications. This study presents an experimental campaign conducted on different FRCM composites comprised of glass, carbon, or steel fibers embedded within two different cementitious matrices and applied to concrete prisms. The single-lap direct-shear test was used to study the stress-transfer mechanism between the FRCM composite and the concrete substrate. Two different composite bonded lengths were investigated. Debonding occurred at the matrix-fiber interface for some of the composites tested and at the concrete-matrix interface for others. This work contributes to the study of the bond behavior of FRCM composites, which represents a key issue for the effectiveness of FRCM composite strengthening.

A New Pull-Out Test to Study the Bond Behavior of Fiber Reinforced Cementitious Composites

2017 ◽  
Vol 747 ◽  
pp. 258-265 ◽  
Author(s):  
Tommaso D'Antino ◽  
Francesca Giulia Carozzi ◽  
Pierluigi Colombi ◽  
Carlo Poggi
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Pull Out ◽  
The Matrix ◽  
Set Up ◽  
High Strength Fiber ◽  
Fiber Reinforced Cementitious Composites

Fiber reinforced cementitious matrix (FRCM) composites are gaining increasing popularity in the civil engineering community. FRCM composites are comprised of high-strength fiber textiles embedded within inorganic matrices that are responsible for the stress-transfer mechanism between the composite and the substrate. Failure of FRCM composites including one layer of textile is generally reported to be debonding of the fibers from the embedding matrix. Therefore, the bond behavior of the matrix-fiber interface is of critical importance for these types of composites.This paper presents the results of an experimental campaign carried out to investigate the bond behavior of an FRCM composite comprising PBO fibers. Specimens were tested using a newly-developed pull-out test set-up. The results obtained are compared with those obtained by different authors on single-lap direct-shear tests with the same FRCM composite.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Investigation of Fiber-Reinforced Modified Epoxy Resin Composites

2012 ◽  
Vol 510-511 ◽  
pp. 577-584 ◽  
Author(s):  
A. Quddos ◽  
Mohammad Bilal Khan ◽  
R.N. Khan ◽  
M.K.K. Ghauri
Keyword(s):  
Epoxy Resin ◽  
High Strength ◽  
Polymeric Matrix ◽  
Fiber Reinforced Composites ◽  
Resin Matrix ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Epoxy Resin Matrix ◽  
The Matrix ◽  
Modified Epoxy

The impregnation of the fiber with a resin system, the polymeric matrix with the interface needs to be properly cured so that the dimensional stability of the matrix and the composite is ensured. A modified epoxy resin matrix was obtained with a reactive toughening agent and anhydride as a curing agent. The mechanical properties of the modified epoxy matrix and its fiber reinforced composites were investigated systematically. The polymeric matrix possessed many good properties, including high strength, high elongation at break, low viscosity, long pot life at room temperature, and good water resistance. The special attentions are given to the matrix due to its low out gassing, low water absorption and radiation resistance. In addition, the fiber-reinforced composites showed a high strength conversion ratio of the fiber and good fatigue resistance. The dynamic and static of the composite material were studied by thermo gravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) with EDX. The influences of processing technique such as curing and proper mixing on the mechanical and interfacial properties were determined. The results demonstrated that the modified epoxy resin matrix is very suitable for applications in products fabricated with fiber-reinforced composites.

The Flexural Strength of Glass Fiber Reinforced Polyester Filled with Aluminum Tri-Hydroxide and Montmorillonite

2018 ◽  
Vol 772 ◽  
pp. 28-32 ◽  
Author(s):  
Sunarto Kaleg ◽  
Dody Ariawan ◽  
Kuncoro Diharjo
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Glass Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
The Matrix

Aluminum tri-hydroxide (ATH) and montmorillonite (MMT) are capable to enhance flame retardancy of glass fiber reinforced polymer (GFRP). Nevertheless, the combination of both flame retardant fillers on changes in the mechanical properties of GFRP is not yet known. The characterization of flexural strength and scanning electron microscope (SEM) observation on GFRP composite has been done. The result of flexural properties testing shows that the addition of ATH or MMT or a combination of both on the GFRP causes a decrease in flexural strength. GFRP with increased ATH loading causes an increase in elastic modulus. Contrarily, the MMT addition causes a decrease in the elastic modulus of the GFRP composite. SEM results on the fractured samples show that the high content of ATH or MMT in the UP tends to agglomerate thus showing visible holes that were formed from the filler particles pulled out from the matrix.

scholarly journals The change in impermeability of steel fiber reinforced concrete with high strength cement-sand matrix at heating

2020 ◽  
Vol 17 (1) ◽  
pp. 150-155
Author(s):  
V. A. Dorf ◽  
◽  
R. O. Krasnovskij ◽  
D. E. Kapustin ◽  
P. S. Sultygova ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Heating Temperature ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Fiber Concrete ◽  
The Matrix ◽  
Steel Fiber Concrete

The paper considers the effects of high temperatures in case of fire on the change in impermeability of steel fiber reinforced concrete having a high-strength cement-sand matrix and various content of fiber of different types, sizes, and strength. It is shown that in the temperature range from 20° to 1100° C in the diagram “Heating temperature - impermeability class», the matrix and steel fiber concrete(SFC) have a S-shaped character, and in case of heating temperature of over 100 °C, there comes a distinct decrease in impermeability.

scholarly journals Implementation of the ultrasonic through-transmission technique for the elastic characterization of fiber-reinforced laminated composite

DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 153-161
Author(s):  
Carlos A. Meza ◽  
Ediguer E. Franco ◽  
Joao L. Ealo
Keyword(s):  
Laminated Composites ◽  
Weight Ratio ◽  
Laminated Composite ◽  
High Strength ◽  
Mechanical Tests ◽  
Fiber Reinforced ◽  
Transmission Technique ◽  
Laminated Materials

Laminated composites are widely used in applications when a high strength-to-weight ratio is required. Aeronautic, naval and automotive industries use these materials to reduce the weight of the vehicles and, consequently, fuel consumption. However, the fiber-reinforced laminated materials are anisotropic and the elastic properties can vary widely due to non-standardized manufacturing processes. The elastic characterization using mechanical tests is not easy, destructive and, in most cases, not all the elastic constants can be obtained. Therefore, alternative techniques are required to assure the quality of the mechanical parts and the evaluation of new materials. In this work, the implementation of the ultrasonic through-transmission technique and the characterization of some engineering materials is reported. Isotropic materials and laminated composites of carbon fiber and glass fiber in a polymer matrix were characterized by ultrasound and mechanical tests. An improved methodology for the transit time delay calculation is reported.

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