scholarly journals Pullout Behavior of Bundled Aramid Fiber in Fiber-Reinforced Cementitious Composite

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1746 ◽  
Author(s):  
Toshiyuki Kanakubo ◽  
Saki Echizen ◽  
Jin Wang ◽  
Yu Mu
Keyword(s):  
Crack Width ◽  
Maximum Load ◽  
Aramid Fiber ◽  
Matrix Cracking ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Integral Calculus ◽  
The Matrix ◽  
Pullout Load ◽  
Bridging Law

The tensile performance of fiber-reinforced cementitious composite (FRCC) after first matrix cracking is characterized by a tensile stress–crack width relationship called the bridging law. The bridging law can be obtained by an integral calculus of forces carried by individual bridging fibers considering the effect of the fiber inclination angle. The main objective of this study is to investigate experimentally and evaluate the pullout behavior of a single aramid fiber, which is made with a bundling of original yarns of aramid fiber. The bundled aramid fiber has a nonsmooth surface, and it is expected to have good bond performance with the matrix. The test variables in the pullout test are the thickness of the matrix and the inclined angle of the fiber. From the test results, the pullout load–slip curves showed that the load increases lineally until maximum load, after which it decreases gradually. The maximum pullout load and slip at the maximum load increase as the embedded length of the fiber becomes larger. The pullout load–crack width relationship is modeled by a bilinear model, and the bridging law is calculated. The calculated result shows good agreement with the experimental curves obtained by the uniaxial tension test of aramid–FRCC.

scholarly journals Modeling of Bridging Law for Bundled Aramid Fiber-Reinforced Cementitious Composite and its Adaptability in Crack Width Evaluation

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 179
Author(s):  
Daiki Sunaga ◽  
Takumi Koba ◽  
Toshiyuki Kanakubo
Keyword(s):  
Fiber Orientation ◽  
Crack Width ◽  
Volume Fraction ◽  
Characteristic Point ◽  
Crack Opening ◽  
Aramid Fiber ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Bridging Law

Tensile performance of fiber-reinforced cementitious composite (FRCC) after first cracking is characterized by fiber-bridging stress–crack width relationships called bridging law. The bridging law can be calculated by an integral calculus of forces carried by individual fibers, considering the fiber orientation. The objective of this study was to propose a simplified model of bridging law for bundled aramid fiber, considering fiber orientation for the practical use. By using the pullout characteristic of bundled aramid fiber obtained in the previous study, the bridging laws were calculated for various cases of fiber orientation. The calculated results were expressed by a bilinear model, and each characteristic point is expressed by the function of fiber-orientation intensity. After that, uniaxial tension tests of steel reinforced aramid-FRCC prism specimens were conducted to obtain the crack-opening behavior and confirm the adaptability of the modeled bridging laws in crack-width evaluation. The experimental parameters are cross-sectional dimensions of specimens and volume fraction of fiber. The test results are compared with the theoretical curves calculated by using the modeled bridging law and show good agreements in each parameter.

Effect of multiple matrix cracking on crack bridging of fiber reinforced engineered cementitious composite

2020 ◽  
Vol 54 (26) ◽  
pp. 3949-3965 ◽  
Author(s):  
Xuan Zheng ◽  
Jun Zhang ◽  
Zhenbo Wang
Keyword(s):  
Tensile Test ◽  
Crack Spacing ◽  
Matrix Cracking ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Crack Bridging ◽  
Engineered Cementitious Composite ◽  
Fiber Bridging

In the present paper, a modified micromechanics based model that describes the crack bridging stress in randomly oriented discontinuous fiber reinforced engineered cementitious composite is developed. In the model, effect of multiple matrix cracking on fiber embedded length, which in turn influencing fiber bridging in the composite, is taken into consideration. First, crack spacing of high strength-low shrinkage engineered cementitious composite was experimentally determined by photographing the specimen surface at some given loading points during uniaxial tensile test. The diagram of average cracking spacing and loading time of each composite is obtained based on above data. Then, fiber bridging model is modified by introducing a revised fiber embedment length as a function of crack spacing. The model is verified with uniaxial tensile test on both tensile strength and crack opening. Good agreement between model and test results is obtained. The modified model can be used in design and prediction of tensile properties of fiber reinforced cementitious composites with characteristics of multiple matrix cracking.

Chloride Ion Penetrability of HPFRCC after Loading

2014 ◽  
Vol 507 ◽  
pp. 242-244
Author(s):  
Kyung Joon Shin
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
High Performance Fiber ◽  
Inherent Problem ◽  
Durability Performance

Cracking is one of the most important factors in the serviceability as well as durability performance of concrete structures. Recently, it was recognized that a high performance fiber-reinforced cementitious composite (HPFRCC) provides a possible solution to this inherent problem of cracking by smearing one or several dominant cracks into many distributed microcracks. The purpose of the present study is to explore the ductility characteristics of HPFRCC. The permeability of HPFRCC after subjected to different load levels were measured to identify the effect of reduced cracking among the mixtures. It was confined that the permeability of proposed mixtures was lower than that without microfibers. This means that the proposed materials can reduce the crack width greatly at the same applied loads

scholarly journals Natural Composite Reinforced by Lontar (Borassus flabellifer) Fiber: An Experimental Study on Open-Hole Tensile Strength

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Jefri Bale ◽  
Kristomus Boimau ◽  
Marselinus Nenobesi
Keyword(s):  
Tensile Strength ◽  
Unsaturated Polyester ◽  
Specific Area ◽  
Matrix Cracking ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Hole Configuration ◽  
The Matrix

A research has been conducted in the present study to investigate the effect of hole configuration on tensile strength of lontar fiber-reinforced composites. The lontar fiber-reinforced composites used in this study were produced by hand lay-up process. The lontar fiber-reinforced composites consist of short random fiber of 5 cm that contains 32% of nominal fiber volume as the reinforcement and unsaturated polyester as the matrix. The results show that the differences of hole configuration have an effect on tensile strength of lontar fiber-reinforced composites. It is found that the specific area of four-hole specimens experiences smaller strain propagation due to the redistributed stress and no stress passes through the hole. The damage of lontar fiber-reinforced composites with different hole configurations in tension is fairly straight and transverse to the loading axis, where the initial damage occurs in the form of matrix cracking, propagates into interfacial failure in form of delamination, and ultimately failed mainly due to the fiber breakage.

scholarly journals Flexural Characteristics of Functionally Graded Fiber-Reinforced Cementitious Composite with Polyvinyl Alcohol Fiber

2021 ◽  
Vol 5 (4) ◽  
pp. 94
Author(s):  
Toshiyuki Kanakubo ◽  
Takumi Koba ◽  
Kohei Yamada
Keyword(s):  
Polyvinyl Alcohol ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Maximum Load ◽  
Functionally Graded ◽  
Bending Test ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Four Point Bending

The objective of this study is to investigate the flexural characteristics of functionally graded fiber-reinforced cementitious composite (FG-FRCC) concerning the fiber volume fraction (Vf) varying in layers and the layered effect in bending specimens. The FG-FRCC specimens, in which Vf increases from 0% in the compression zone to 2% in the tensile zone, are three-layered specimens using polyvinyl alcohol (PVA) FRCC that are fabricated and tested by a four-point bending test. The maximum load of the FG-FRCC specimens exhibits almost twice that of homogeneous specimens, even when the average of the fiber volume fraction in the whole specimen is 1%. The result of the section analysis, in which the stress–strain models based on the bridging law (tensile stress–crack width relationship owned by the fibers) consider the fiber orientation effect, shows a good adaptability with the experiment result.

Numerical Investigation of Reinforcing a Masonry Column with Fiber Reinforced Strain Hardening Cementitious Composite

2015 ◽  
Vol 1122 ◽  
pp. 269-272
Author(s):  
Marek Jašek ◽  
Jiri Brozovsky
Keyword(s):  
Strain Hardening ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Short Fibers ◽  
Fine Grained ◽  
Numerical Assessment ◽  
The Matrix ◽  
New Generation

Fiber reinforced strain hardening cementitious composite is very deformable fine-grained concrete with the matrix based on Portland cement reinforced with short fibers. This composite material represents a new generation of high performance concrete (HPC) and it is also known as flexible concrete. Its characteristic property is that after reaching the strength when the first crack appears "hardening" of the material occurs, i.e. increases the stress and at the same time increases the strain until the ultimate strength of the material is achieved. One of the possibilities is the use of composites in the reconstruction and rehabilitation of buildings. The paper deals with the numerical assessment of the possibility of using fiber reinforced strain hardening cementitious composite during the reinforcement of an axially loaded brick column.

scholarly journals Non-Steady First Matrix Cracking of Fiber-Reinforced Ceramics

2020 ◽  
Author(s):  
Huan Wang
Keyword(s):  
Steady State ◽  
Crack Opening ◽  
Ceramic Matrix Composites ◽  
Matrix Cracking ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Opening Displacement ◽  
Interface Shear ◽  
The Matrix ◽  
Lag Model

Matrix cracking affects the reliability and safety of fiber-reinforced ceramic-matrix composites during operation. The matrix cracking can be divided into two types, that is, steady state crack and non-steady state cracking. This chapter is about the non-steady stable cracking of fiber-reinforced CMCs. The micro stress field of fiber, matrix, and interface shear stress along the fiber direction is analyzed using the shear-lag model. The relationship between the crack opening displacement and the crack surface closure traction is derived. The experimental first matrix cracking stress of different CMCs are predicted.

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.

Sign in / Sign up

Export Citation Format

Share Document