Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites

2014 ◽  
Vol 600 ◽  
pp. 421-432 ◽  
Author(s):  
Saulo Rocha Ferreira ◽  
Paulo Roberto Lopes Lima ◽  
Flávio Andrade Silva ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Dimensional Stability ◽  
Sisal Fiber ◽  
Multiple Cracks ◽  
Direct Tension ◽  
Wetting And Drying ◽  
Pull Out ◽  
Higher Dimensional ◽  
Bending Loads ◽  
Fiber Matrix ◽  
Sisal Fibers

Cycles of wetting and drying can change the microstructure of vegetable fibers through a mechanism known as hornification, which modifies the polymeric structure of the fiber-cells resulting in a higher dimensional stability. In the present work the influence of hornification on the sisal fiber-matrix bond adhesion as well as in the sisal fiber dimensional stability and mechanical behaviour under direct tension was evaluated. Furthermore, cementitious composites reinforced with randomly dispersed hornified sisal fibers were developed and characterized under bending loads. The results show that the tensile strength and strain at failure of the hornified sisal fibers were increased by about 5% and 39%, respectively, whereas the modulus of elasticity was reduced by 9%. The fibers also presented higher dimensional stability with the hornification process. The fiber-matrix bonding was improved and the pull-out resistance of the fibers submitted to ten cycles of wetting and drying was increased by about 40% to 50%. The higher fiber-matrix bond strength contributed to an increase in the ductility and post-cracking behaviour of the composite. The fracture process was characterized by the formation of multiple cracks with the hornified sisal fibers presenting a higher ability to bridge and arrest the cracks.

Evaluation of Interfacial Properties of Sisal Fiber Reinforced High Density Polyethylene (HDPE) Composites

2007 ◽  
Vol 334-335 ◽  
pp. 625-628 ◽  
Author(s):  
Yan Li ◽  
Hong Xia Deng ◽  
Ye Hong Yu
Keyword(s):  
Natural Fiber ◽  
Fiber Surface ◽  
Interfacial Properties ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Statistical Parameters ◽  
Pull Out ◽  
Bonding Properties ◽  
Fiber Surface Treatment ◽  
Sisal Fibers

Statistical methods were employed to study the structure characteristics of sisal fibers. Two types of fiber surface treatment methods, namely chemical bonding and oxidization were used to improve the interfacial bonding properties of sisal fiber reinforced HDPE (sisal/HDPE) composites. Interfacial properties were evaluated by single fiber pull out test. The interfacial shear strength (IFSS) was calculated and analyzed by the statistical parameters. The results were compared with those obtained by traditional ways. A novel method which could more accurately evaluate the interfacial properties between natural fiber and polymeric matrices was proposed.

Effect of Treatment of Sisal Fiber on Morphology, Mechanical Properties and Fiber-Cement Bond Strength

2014 ◽  
Vol 634 ◽  
pp. 410-420 ◽  
Author(s):  
Rogério de Jesus Santos ◽  
Paulo Roberto Lopes Lima
Keyword(s):  
Tensile Strength ◽  
Factorial Design ◽  
Morphological Characterization ◽  
Sisal Fiber ◽  
Pull Out ◽  
Gradual Loss ◽  
The Matrix ◽  
Number Of Cycles ◽  
Sisal Fibers ◽  
Dimensional Instability

The dimensional instability of vegetable fibers due to hygroscopicity results in a gradual loss of adherence in cement based composites which, when in service, are submitted to a natural variation of humidity. Such an effect reduces the contribution of the fiber as a reinforcement and can cause the early rupture of the material. In this work, a treatment of the sisal fibers is performed with the applying of wetting-drying cycles in order to alter their crystalline structure and improve the dimensional stability of the fiber to withstand the variation of humidity: 6, 10, 20, 30 and 34 cycles were applied in order to evaluate the effect on the properties of fiber; a tensile test, the morphological characterization (MEV) and the evaluation of the chemical structure of fiber were carried out. The effect of the treatment on fiber-matrix behavior was evaluated using the pull-out test. Embedded lengths of 16, 20, 30, 40 and 44 mm were defined through a factorial design and used in the test. It is verified that the use of 10 wetting-drying cycles causes less damage to the tensile strength and the elastic modulus of the fiber and contributes to a better adherence with the matrix, with an increase of up to 23 % compared with the untreated fiber. The statistical analysis of the interaction effect between the studied factors, using 2K factorial design with central composite design, indicates that the number of cycles can be decreased when using a longer length of the embedded fiber.Keywords: wetting-drying cycles, pull out test, tensile strength..

Effect of Natural Fiber Hornification on the Fiber Matrix Interface in Cement Based Composite Systems

2015 ◽  
Vol 668 ◽  
pp. 118-125 ◽  
Author(s):  
Saulo Rocha Ferreira ◽  
Flávio de Andrade Silva ◽  
Paulo Roberto Lopes Lima ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Natural Fiber ◽  
Cell Structure ◽  
Natural Fibers ◽  
High Water ◽  
Wetting And Drying ◽  
Fiber Cells ◽  
Pull Out ◽  
Higher Dimensional ◽  
Microstructural Surface ◽  
Efficiency Rate

Several fiber treatments can be applied to mitigate the high water absorption of vegetal fibers. Wetting and drying cycles are usually performed in the industry of paper and cellulose to reduce the volume variation of the natural fibers. This procedure stiffens the polymeric structure of the fiber-cells (process known as hornification) resulting in a higher dimensional stability. The aim of this study is to determine the effect of the hornification on the interface of natural fibers. For this purpose, cycles of wet and drying was applied on Sisal, Curaua and Jute fibers. Fiber pull-out tests were performed in embedment lengths of 25mm. Furthermore, the influence of the hornification in the fibers mechanical (under tensile loading) and microstructural (surface modifications of the fiber and changes in the fiber-cell structure) behavior were investigated. The results indicate changes on the tensile strength and strain capacity of the studied fibers, showing that morphology and chemical composition play an important role on the efficiency rate of hornification.

scholarly journals Influence of Sisal Fibers on the Properties of Rammed Earth

2019 ◽  
Vol 8 (9S2) ◽  
pp. 663-667
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Bond Strength ◽  
Strength Properties ◽  
Coarse Sand ◽  
Sisal Fiber ◽  
Rammed Earth ◽  
Pull Out ◽  
Earth Blocks ◽  
Sisal Fibers

The use of rammed earth has been increasing widely during recent years in many countries as an alternative material for building houses due to its valuable characteristics such as affordability, environment friendly, comfort, strength and durability. This thesis presents the result of an experimental study to evaluate the compressive strength and bond strength properties of untreated, treated bamboo splints and steel reinforced cement stabilized rammed earth blocks. To overcome the deficiencies of blocks, sisal fibers are added to improve the performance of CSRE blocks. Fibers are secondary reinforced materials and acts as crack arresters which improves the strength of cement stabilized rammed earth blocks. In this experimental study, red soil is mixed by adding four different percentages (5%, 10%, 15%, and 20%) of OPC and sisal fiber with 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% by weight of soil respectively. The bamboo splints were treated by soaking them in chemical solution of boric acid, Copper -Sulphate and Potassium Di-chromate (1.5:3:4).The resin-based adhesive with coarse sand will be applied to the top of bamboo splints. After 28days of curing period the cubes were tested for compressive strength, pull-out test is done for a series of CSRE blocks in which Bamboo splints and steel bars are embedded to find out its bond strength.

scholarly journals Characterization and treatment of sisal fiber residues for cement-based composite application

2014 ◽  
Vol 34 (5) ◽  
pp. 812-825 ◽  
Author(s):  
Paulo R. L. Lima ◽  
Rogério J. Santos ◽  
Saulo R. Ferreira ◽  
Romildo D. Toledo Filho
Keyword(s):  
Tensile Testing ◽  
Agricultural Residues ◽  
Sisal Fiber ◽  
Agricultural Product ◽  
Flexural Test ◽  
Fiber Production ◽  
Commercial Use ◽  
Pull Out ◽  
Sisal Fibers ◽  
Scanning Electron

Sisal fiber is an important agricultural product used in the manufacture of ropes, rugs and also as a reinforcement of polymeric or cement-based composites. However, during the fiber production process a large amount of residues is generated which currently have a low potential for commercial use. The aim of this study is to characterize the agricultural residues by the production and improvement of sisal fiber, called field bush and refugo and verify the potentiality of their use in the reinforcement of cement-based composites. The residues were treated with wet-dry cycles and evaluated using tensile testing of fibers, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Compatibility with the cement-based matrix was evaluated through the fiber pull-out test and flexural test in composites reinforced with 2 % of sisal residues. The results indicate that the use of treated residue allows the production of composites with good mechanical properties that are superior to the traditional composites reinforced with natural sisal fibers.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

scholarly journals Dynamic Single-Fiber Pull-Out of Polypropylene Fibers Produced with Different Mechanical and Surface Properties for Concrete Reinforcement

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 722
Author(s):  
Enrico Wölfel ◽  
Harald Brünig ◽  
Iurie Curosu ◽  
Viktor Mechtcherine ◽  
Christina Scheffler
Keyword(s):  
Tensile Strength ◽  
Dynamic Loading ◽  
Melt Spinning ◽  
Structural Changes ◽  
High Surface ◽  
Single Fiber ◽  
Scanning Calorimetry ◽  
Matrix Interaction ◽  
Pull Out ◽  
Fiber Matrix

In strain-hardening cement-based composites (SHCC), polypropylene (PP) fibers are often used to provide ductility through micro crack-bridging, in particular when subjected to high loading rates. For the purposeful material design of SHCC, fundamental research is required to understand the failure mechanisms depending on the mechanical properties of the fibers and the fiber–matrix interaction. Hence, PP fibers with diameters between 10 and 30 µm, differing tensile strength levels and Young’s moduli, but also circular and trilobal cross-sections were produced using melt-spinning equipment. The structural changes induced by the drawing parameters during the spinning process and surface modification by sizing were assessed in single-fiber tensile experiments and differential scanning calorimetry (DSC) of the fiber material. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements were applied to determine the topographical and wetting properties of the fiber surface. The fiber–matrix interaction under quasi-static and dynamic loading was studied in single-fiber pull-out experiments (SFPO). The main findings of microscale characterization showed that increased fiber tensile strength in combination with enhanced mechanical interlocking caused by high surface roughness led to improved energy absorption under dynamic loading. Further enhancement could be observed in the change from a circular to a trilobal fiber cross-section.

Effect of Sisal Fiber Surface Treatments on Sisal Fiber Reinforced Polypropylene (PP) Composites

2014 ◽  
Vol 906 ◽  
pp. 167-177 ◽  
Author(s):  
Hou Lei Gan ◽  
Lei Tian ◽  
Chang Hai Yi
Keyword(s):  
Surface Morphology ◽  
Morphological Changes ◽  
Fiber Surface ◽  
Atmospheric Plasma ◽  
Single Fiber ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Polypropylene Composites ◽  
Pull Out ◽  
Debonding Process

Abstract: The Interface of sisal fiber which was treated by using alkali, potassium permanganate, atmospheric plasma and silane reinforced polypropylene composites were investigated by single fiber pull-out testes and surface morphology were studied. The results indicated that the morphological changes observed on the sisal fiber surface were obviously evident. Untreated, permanganate and plasma treated sisal fiber reinforced PP show a stable debonding process. Silane treated sisal fiber reinforced PP show an unstable debonding process. Single fiber pull-out tests indicated that the IFSS value was in the order of FIB < FIBKMnO4 < FIBP < FIBKH-550 < FIBKH-570. As can be seen from surface morphology of pull-out fiber, a little of PP resin was adhered to the pull-out FIB, FIBKMnO4, FIBP of sisal fiber. In contrast, PP resin at the surface of pull-out fiber was flaked off and sisal fibril was drawn out from sisal fiber were observed from pull-out fibers of FIBKH-550 and FIBKH-570.

Test Comparison Research Mechanics Performance between Sisal Fiber Concrete and Rubber Powder Concrete

2011 ◽  
Vol 243-249 ◽  
pp. 494-498
Author(s):  
Hui Ming Bao
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Sisal Fiber ◽  
Environment Friendly ◽  
Rubber Powder ◽  
Comparison Research ◽  
Mechanics Performance ◽  
Fiber Concrete ◽  
Sisal Fibers

By means of the tests on the mechanics performance of the reinforcing concrete mixed with sisal fibers or rubber powder of certain content are investigated. The compressive strength, tensile strength and flexural strength, etc. are compared. The test indicates that when the test condition is same, the compressive strength, tensile strength and flexural strength of the sisal fibers concrete are better than those of the rubber powder’s. The sisal fiber concrete is environment friendly than the rubber powder concrete. And it has widely value of spread and utilization.

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