scholarly journals An experimental study on damaged cementitious mortars repaired by glass/epoxy composite materials

2020 ◽  
Vol 15 (1) ◽  
pp. 113-128
Author(s):  
Chouaib Aribi ◽  
Aissa Bouaissi ◽  
Brahim Safi ◽  
Mohammed Saidi

Abstract This paper presents an experimental investigation on the post-repair flexural response of mortars with and without damage. In order to improve the mechanical properties of the damaged mortars, which were subjected to different loads ranging between 40 % and 90 %, the mortars specimens were reinforced and repaired using two different composite materials, the first with only epoxy resin, while the second consisted of a mixture of epoxy resin and glass fiber. The results show a significant improvement in the stiffness damaged. Therefore, the reinforced specimens by a layer of resin on the lower side surface increased the bending strength by 58 %, when compared to those control samples. The reinforcement using composite resin-fiber of glass exhibited considerable increases in the safety of constructions. The SEM images of damaged samples with and without repair, revealed the impact of reinforced glass fibers-mortar on the matrix-mortar by improving theirs mechanical performances.

2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.


2013 ◽  
Vol 471 ◽  
pp. 335-340 ◽  
Author(s):  
A.M.T. Arifin ◽  
S. Abdullah ◽  
Rozli Zulkifli ◽  
D.A. Wahab

This paper presents the investigation of composite materials lamination using different materials in the structure of lamination. The main purpose of the study is to evaluate the behaviour of characteristics in composite materials subjected to difference of fatigue loading, leading to understand the criteria that influence the behaviour of composite lamination structure. Therefore, in this research, the orientation of lamination structure used is 00/900and the material selected for the study were chopped strand mat (csm) and woven roving fabric (wr) as a reinforcement and the matrix used were polyester and epoxy resin. The composite lamination structure was produced using hand lay-up technique. The fatigue condition experiment of composite materials in this research was carried under tension-tension loading. With difference in fatigue loading condition, the lifetime of composite structure will be different and the cracking phenomenon in the structure will also be different. It is suggested that, different number of lamination and amount of reinforcement and matrix, produce a variety of materials characteristic with respect to elasticity of material. An implication of the study in this research showed various behaviour of composite materials with different materials used and it showed a difference phenomenon in comparison to metalic materials.


2014 ◽  
Vol 983 ◽  
pp. 94-98 ◽  
Author(s):  
Li Jun Wang ◽  
Jian Hui Qiu ◽  
Eiichi Sakai

The melting mixing was applied in the preparation of Multiwalled carbon nanotubes/Polycarbonate (MWCNTs/PC) nanocomposites. MWCNTs/PC nanocomposites with different MWCNTs contents were prepared under different injection conditions. The mechanical property of nanocomposites was comparatively investigated. The results demonstrated that: the tensile property of the nanocomposites was slightly improved by MWCNTs content increasing; but as the MWCNTs contents went on to increase to 10wt%, the tensile strength and bending strength were obviously decreased about 35% and 47%, respectively, but the impact strength and hardness were increased. The center hardness of MWCNTs/PC nanocomposites was greater than the surface hardness. Besides, the changes on the mechanical properties of the nanocomposites were studies by changing the injection conditions. By Scanning Electron Microscopy (SEM) observation, the microstructure and morphology of nanocomposites were analyzed, revealing that the center of the nanocomposite distributed more MWNTs, and the injection conditions would affect the MWNTs’ dispersion in the matrix and the interfacial interaction between MWCNTs and PC.


2021 ◽  
Author(s):  
Chenglin Zhang ◽  
Guohua Gu ◽  
Shuhua Dong ◽  
Zhitao Lin ◽  
Chuncheng Wei ◽  
...  

Abstract In this study, the nonisothermal differential scanning calorimetry (DSC) was carried out to evaluate the curing reaction of fiber/epoxy laminates. The optimal curing process of the prepreg was obtained by T-β extrapolation method and nth-order reaction curing kinetic equation. The bending strength, impact strength and thermodynamic properties of the composite laminates with different ply orientations were investigated, respectively. The results show that the apparent activation energy and the reaction order of the prepregs are 82.89 kJ/mol and 0.92, respectively. The curing process of carbon fiber/epoxy resin prepreg is 130 ℃ /60min + 160 ℃/30 min. The bending strength of [0]10 laminate is 1948.3 MPa, which is 11.8 times higher than that of [+ 45/-45]5s laminate, and 96.4% higher than that of [0/90]5s laminate. The impact strength of [0]10 laminate is higher than that of [+ 45/-45]5s and [0/90]5s laminates. The glass transition temperature (Tg) of the laminates is 142 ~ 146 ℃, and the loss factor of [0]10 laminate is significantly higher than that of [+ 45/-45]5s and [0/90]5s laminates. This research provides a theoretical basis for the further application of prepregs to fiber composite materials.


2020 ◽  
Vol 19 (3) ◽  
pp. 187-194
Author(s):  
Oki Kurniawan ◽  
Willy Artha Wirawan ◽  
Akbar Zulkarnain

Abstract The use of composite materials has been developed in the railroad transportation industry sector in Indonesia. For example, PT INKA has used composite materials with fiber glass reinforcement. The purpose of this study is to determine the characteristics of tensile strength and bending strength of the composite material so that it can be proposed to be further developed and utilized by the manufacturing industry, especially the railroad industry. In this study, 4 types of matrix variations were examined, namely epoxy, repoxy, polyester, and bhispenol using fiber glass reinforcement. Tensile strength and bending strength tests were performed in accordance with the ASTM D-638 and the ASTM D-790 standards, respectively. The results of this study indicate that the variation of the matrix is very influential on the tensile strength and bending strength of composite materials. Keywords: composite material, glass fiber, tensile strength, bending strength  Abstrak Penggunaan material komposit mulai banyak dikembangkan di sektor industri trasportasi kereta api di Indone-sia. Sebagai contoh, PT INKA sudah menggunakan material komposit dengan penguat serat gelas. Tujuan penelitian ini adalah untuk mengetahui karakteristik kekuatan tarik dan kekuatan bending material komposit agar dapat diusulkan untuk lebih dikembangkan dan dimanfaatkan oleh industri manufaktur, khususnya industri kereta api. Pada penelitian ini digunakan 4 jenis variasi matriks, yaitu epoxy, repoxy, polyester, dan bhispenol dengan menggunakan penguat serat gelas. Pengujian kekuatan tarik menggunakan standar ASTM D-638 dan pengujian bending menggunakan standar ASTM D-790. Hasil studi ini menunjukkan bahwa variasi matriks sangat berpengaruh pada kekuatan tarik maupun kekuatan bending material komposit. Kata-kata kunci: material komposit, serat gelas, kekuatan tarik, kekuatan bending


2013 ◽  
Vol 785-786 ◽  
pp. 533-536 ◽  
Author(s):  
Shi Bao Li ◽  
Yi Min Zhao ◽  
Jian Feng Zhang ◽  
Cheng Xie ◽  
Dong Mei Li ◽  
...  

A novel PMMA-ZrO2 composite (PZC) was prepared by resin infiltrated to ceramic method. The composite mechanical properties were evaluated and correlated to its microstructure. Partially sintered zirconia ceramics (PSZC) were made by isostatic pressing and partially sintering. Subsequently, the PZC was prepared by vacuum infiltrating prepolymerized MMA into PSZC, followed by in-situ polymerization. When PSZC-70% was used as the matrix, the bending strength, elastic modulus, and fracture toughness of the prepared composite i.e PZC-70% were 202.56±12.09 MPa, 58.71±3.98 GPa, and 4.60±0.26 MPa·m1/2, corresponding to 25.69%, 23.31%, and 169.01% improvement, respectively, in comparison with the control matrix. Among them, the fracture toughness improvement was the most prominent. According to SEM images of the fracture surfaces, each pore of zirconia skeleton was filled by organic resin contributing to the bending strength improvement. These weak interfaces between zirconia skeleton and organic resin absorbed energy and terminated the growth of microcracks which might be responsible for significant improvement in fracture toughness. This PZC material is anticipated to be a new member of the dental CAD/CAM family.


2011 ◽  
Vol 391-392 ◽  
pp. 714-718
Author(s):  
Rui Zhou ◽  
Jian Fei Sun ◽  
Ying Jun Yang

Microstructure and mechanical properties of W9Mo3Cr4V high speed steel fabricated by spray deposition have been studied. Spray deposited W9Mo3Cr4V high speed steel has a typical equiaxed structure which is finer and more homogeneous with a grain size of 20-30 micrometer compared with conventional casted counterparts. There are pores in the matrix of the deposited steel, which involve gas porosity, filling porosity and solidification shrinkage. As-deposited high speed steel is mainly composed of martensite, austenite and carbides which comprise MC carbide and M6C carbide. Mechanical properties show that the hardness and bending strength of the as-deposited steel are higher than that of the conventionally casted ones. However, impact toughness of the high speed steel is lower than that of the conventionally casted steel, which can be attributed to the existence of porosities and M6C carbides which reduce the impact toughness of high speed steels.


2010 ◽  
Vol 150-151 ◽  
pp. 727-731 ◽  
Author(s):  
Zhi Yi Huang ◽  
Shao Rong Lu ◽  
Zhi You Yang ◽  
Chun He Yu ◽  
Dong Guo

Liquid crystal polyurethane (LCPBI) containing biphenylnate and imide units was synthesized and characterized and used to modify the conventional epoxy resin (E-51). Experimental results revealed that the impact strength of the epoxy resin modified with LCPBI was 2.5 times higher than that of unmodified epoxy resin, and the tensile strength as well as the bending strength was also improved. The thermal decomposition temperature of modified systems was also 15-20oC higher than that of the unmodified system, and the fracture structures of the blends was investigated by SEM.


2012 ◽  
Vol 482-484 ◽  
pp. 1959-1962 ◽  
Author(s):  
Quan Fu Yin ◽  
Ming Wei Di

Lignin/epoxy resin composites were prepared by blending lignin with epoxy resin cured by polyamide. The effect of the content of lignin and polyamide on the mechanical properties of the lignin/epoxy resin composites was studied systemically. And the structure for the blend of lignin and epoxy resin without the curing agent was characterized by Fourier transform infrared spectroscopy (FTIR). The results of mechanical properties test showed that the bending strength of the composites decreases gradually with increasing the content of lignin, while the impact strength increased firstly and then decreased. The bending strength of lignin/epoxy resin composites showed a trend of increasing firstly and then decreasing with the increase of the content of polyamide, while the impact strength exhibited an opposite trend. The density for the composites increased with the addition of lignin, and polyamide exhibited an inconspicuous effect on density of the composites. The FTIR analysis results showed that the epoxy resin could be cured by lignin without polyamide, which concluded that the lignin could catalyze the cross-linking of epoxy resin or react with epoxy resin, and this bonding effect would beneficial to the properties of lignin/epoxy resin composites.


2018 ◽  
Vol 8 (3) ◽  
pp. 3038-3040
Author(s):  
N. Zaman ◽  
S. Ahmed ◽  
M. Sanaullah ◽  
A. U. Rehman ◽  
A. R. Shar ◽  
...  

Synthesis and characterization of polyester nanocomposites was conducted in order to fabricate hybrid composite materials of polyester/montmorillonite (MMT). Polyester based polymeric nanocomposite materials were synthesized by incorporating MMT nanoclay to produce polyester/MMT hybrid materials. Successful efforts were made to fabricate hybrid nanocomposite materials based on matrix (polyester based) and reinforcement (organoclay) through sonication at 6 and 12 hours. Synthesized nanocomposite polymers (polyester/MMT) showed different properties when compared to the properties of MMT and polyester, which confirmed the successful fabrication of the desired material. The finest incorporation of polyester with MMT was verified by UV-Visible spectrophotometer, Fourier tranform-infrared (FTIR) and scanning electron microscopy (SEM). The disappearance of the Si-O characteristic peak was observed in the FTIR spectrum justifying the fabrication of the desired composite materials. Colored SEM images were used to confirm the fine homogenous distribution of organoclay. Black SEM images showed the matrix and reinforcement together. SEM, FTIR and UV-Visible spectroscopic techniques were used to analyze polyester based nanocomposite materials and organoclay was found randomly distributed in the polymeric matrix whereas on the surface was observed to be mostly uniform.


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