Fibre-Cement Paste Transition Zone

1994 ◽  
Vol 370 ◽  
Author(s):  
Vahan Agopyan ◽  
Holmer Savastano
Keyword(s):  
Transition Zone ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Polypropylene Fibres ◽  
Impact Performance ◽  
The Matrix ◽  
Vegetable Fibre ◽  
Electron Image ◽  
Backscattered Electron ◽  
The Impact

AbstractThe characteristics of fibres and paste of ordinary Portland cement transition zone are analysed and correlated to the mechanical properties of the produced composites. The water-cement ratio of the matrix varies from 0.30 to 0.46 and the age of the specimens varies from 7 to 180 days. Composites of vegetable fibres (coir, sisal and malva) are compared with those of chrysotile asbestos and polypropylene fibres. The analysis is made by backscattered electron image (BSEI) and energy dispersive spectroscopy (EDS). Mechanical tests evaluate the composite tensile strength and ductility.Mainly for vegetable fibre composites the transition zone is porous, cracked and rich in calcium hydroxide macrocrystals. These results are directly associated with the fibre-matrix bonding and with the composite mechanical performance. Further studies considering the impact performance of the composites compare the porosity of the transition zone with the toughness of the composites.

scholarly journals Preparation of Long Sisal Fiber-Reinforced Polylactic Acid Biocomposites with Highly Improved Mechanical Performance

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1124
Author(s):  
Zhifang Liang ◽  
Hongwu Wu ◽  
Ruipu Liu ◽  
Caiquan Wu
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Performance ◽  
Tensile Elongation ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
The Matrix ◽  
Blending Process ◽  
Extension Direction

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.

scholarly journals Improvement of the Impact Properties of Composite Laminates by Means of Nano-Modification of the Matrix—A Review

2018 ◽  
Vol 8 (12) ◽  
pp. 2406 ◽  
Author(s):  
Hamed Saghafi ◽  
Mohamad Fotouhi ◽  
Giangiacomo Minak
Keyword(s):  
Composite Laminates ◽  
Cost Effective ◽  
Careful Consideration ◽  
Impact Performance ◽  
Compression After Impact ◽  
The Matrix ◽  
The Right ◽  
2D And 3D ◽  
The Impact ◽  
Selection Of

This paper reviews recent works on the application of nanofibers and nanoparticle reinforcements to enhance the interlaminar fracture toughness, to reduce the impact induced damage and to improve the compression after impact performance of fiber reinforced composites with brittle thermosetting resins. The nanofibers have been mainly used as mats embedded between plies of laminated composites, whereas the nanoparticles have been used in 0D, 1D, 2D, and 3D dimensional patterns to reinforce the matrix and consequently the composite. The reinforcement mechanisms are presented, and a comparison is done between the different papers in the literature. This review shows that in order to have an efficient reinforcement effect, careful consideration is required in the manufacturing, materials selection and reinforcement content and percentage. The selection of the right parameters can provide a tough and impact resistant composite with cost effective reinforcements.

scholarly journals Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Stanislaw Kuciel
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Crystallization Rate ◽  
Mechanical Tests ◽  
Hydrothermal Degradation ◽  
3D Printed ◽  
The Impact ◽  
Different Levels ◽  
Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

scholarly journals Impact and Post-Impact Performance of Sandwich Wall Boards with GFRP Face Sheets and a Web-Foam Core: The Effects of Impact Location

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1714 ◽  
Author(s):  
Yiwei Xia ◽  
Xiaoping Li ◽  
Yu Peng ◽  
Mianheng Lai ◽  
Lu Wang
Keyword(s):  
Mechanical Performance ◽  
Loading Capacity ◽  
Foam Core ◽  
Impact Performance ◽  
Impact Location ◽  
Post Impact ◽  
Sandwich Wall ◽  
Ultimate Loading Capacity ◽  
The Impact ◽  
Ultimate Loading

In recent years, load-bearing exterior sandwich wall boards have been adopted in civil engineering. The exterior walls of structures are often exposed to low velocity impacts such as stones, tools, and windborne debris, etc. The ultimate loading capacity, deformation, and ductility of sandwich walls are weakened by impact loads. In this study, the sandwich wall boards consisted of glass fiber reinforced plastic (GFRP) face sheets and a web-foam core. The core of wall boards was not the isotropic material. There was no doubt that the mechanical performance was seriously influenced by the impact locations. Therefore, it is necessary to carry out an investigation on the impact and post-impact performance of exterior wall boards. A comprehensive testing program was conducted to evaluate the effects of impact locations and impact energies on the maximum contact load, deflection, and contact time. Meanwhile, the compression after impact (CAI) performance of wall boards were also studied. The results indicated that the impact location significantly affects the performance of wall boards. Compared with an un-damaged wall board, the residual ultimate loading capacity of damaged wall boards reduced seriously, which were not larger than 50% of the designed ultimate loading capacity.

Epoxy-matrix nanocomposites reinforced by electrospun polymeric nanofibrous layers: PAN, PA-6,6, and hybrid PAN/PA-6,6

2021 ◽  
pp. 095440622110426
Author(s):  
Farzin Asghari Arpatappeh ◽  
Ali Akbar Gharehaghaji ◽  
Hooshang Nosraty
Keyword(s):  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Electrospun Nanofiber ◽  
The Matrix ◽  
Low Volume ◽  
Enhanced Properties ◽  
The Impact ◽  
Matrix Nanocomposites ◽  
Advanced Applications

Composite materials with nanofibrous reinforcements are capable of high mechanical performance and enhanced properties despite their low volume fraction of reinforcement. In this study, tensile properties of epoxy-matrix nanocomposites were investigated after reinforcing by hand layup method implementation of randomly oriented electrospun nanofiber layers. The reinforcements were produced from polyacrylonitrile (PAN), Polyamide-6,6 (PA-6,6), and their 50/50 hybrid. The results indicated that PAN enhanced the tensile toughness of the matrix by almost 4 times, increasing both the ductility (an expected 23% due to fiber being more elastic than the matrix) and the ultimate tensile strength (a surprising 35% even though the fibers were less stiff than the matrix). These results indicate significant improvements in the impact properties for advanced applications. The results revealed that PA-6,6 did not show the characteristics of a promising reinforcement whether used solely or added to PAN.

scholarly journals Effect of a New Grain Refiner (Al–Ti–Mg–Ce) on Hardness, Tensile, and Impact Properties of Al–7Si Alloy

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 228 ◽  
Author(s):  
Jitao Zhao ◽  
Mingfang Shi ◽  
Zhenqing Wang ◽  
Lidan Xu
Keyword(s):  
Impact Toughness ◽  
Strain Rate ◽  
Tensile Properties ◽  
Rate Sensitivity ◽  
Mechanical Tests ◽  
Hopkinson Pressure Bar ◽  
Grain Refiner ◽  
Impact Properties ◽  
Impact Performance ◽  
The Impact

Through studying the effects of the Al–5Ti-x(Mg–30%Ce) refiner on the microstructure of the Al–7Si alloy, we investigated the hardness, tensile, and impact properties of the Al–Si alloy before and after refinement. The refinement results show that Mg–30%Ce can improve the refinement effect of Al–5Ti on Al–7Si, and also refine α-Al and eutectic Si in Al–7Si. When 2%Mg–30%Ce is added, the refining effect of the aluminum–silicon alloy is most obvious. After refinement, the hardness and tensile properties of the Al–7Si alloy improve. When 2%Mg–30%Ce is added to the refiner, the tensile properties of the Al–Si alloy are the best. Dynamic mechanical tests were conducted on refined Al–7Si alloy. The impact toughness of Al–7Si–(Al–5Ti-2(Mg–30%Ce) improved and the impact toughness reached 34.91 J/cm2, which is 78.7% higher than that of Al–7Si–(Al–5Ti) specimens. The separate Hopkinson pressure bar test results show that, under a high strain rate, the strain rate sensitivity of the prepared Al–Si alloy is significant. The specimens of Al–7Si–(Al–5Ti-2(Mg–30%Ce) demonstrated the best anti-impact performance at the same velocity.

scholarly journals Biopolymer-Waste Fiber Reinforcement for Earthen Materials: Capillary, Mechanical, Impact, and Abrasion Performance

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1819
Author(s):  
Héctor Gonzalez-Calderon ◽  
Gerardo Araya-Letelier ◽  
Sabine Kunze ◽  
Claudia Burbano-Garcia ◽  
Úrsula Reidel ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Fiber Reinforcement ◽  
Impact Performance ◽  
Mechanical Impact ◽  
Chicken Feathers ◽  
Earthen Construction ◽  
The Impact ◽  
Positive Effect ◽  
By Products ◽  
Significant Increment

The poultry industry, highly prevalent worldwide, generates approximately 7.7 × 106 metric tons of chicken feathers (CFs), which become a major environmental challenge due to their disposal when considered waste or due to their energy transformation consumption when considered by-products. CFs are mainly composed of keratin (approximately 90%), which is one of the most important biopolymers whose inherent characteristics make CFs suitable as biopolymer fibers (BPFs). This paper first assesses the morphological and chemical characteristics of these BPFs, through scanning electron microscopy and energy dispersive X-ray spectroscopy, and then evaluates the waste valorization of these BPFs as a sustainable alternative for fiber-reinforcement of earthen mixes intended for earthen construction, such as adobe masonry, rammed earth, and earthen plasters. In particular, four earthen mixes with increasing doses of BPFs (i.e., 0%, 0.25%, 0.5%, and 1% of BPFs by weight of soil) were developed to evaluate the impact of BPF-reinforcement on the capillary, mechanical, impact, and abrasion performance of these earthen mixes. The addition of BPFs did not significantly affect the mechanical performance of earthen mixes, and their incorporation had a statistically significant positive effect on the impact performance and abrasion resistance of earthen mixes as the BPF dose increased. On the other hand, the addition of BPFs increased the capillary water absorption rate, possibly due to a detected increment in porosity, which might reduce the durability of water-exposed BPF-reinforced earthen mixes, but a statistically significant increment only occurred when the highest BPF dose was used (1%).

Polypropylene hybrid composites: Effect of reinforcement of sisal and carbon fibre on mechanical, thermal and morphological properties

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jyoti Agarwal ◽  
Smita Mohanty ◽  
Sanjay K Nayak
Keyword(s):  
Carbon Fibre ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Mechanical Tests ◽  
Critical Stress Intensity Factor ◽  
Morphological Properties ◽  
Morphological Observation ◽  
Sisal Fibre ◽  
Variable Weight ◽  
The Impact

Abstract Polypropylene (PP)/sisal fibre (SF)/carbon fibre (CF) hybrid composites were prepared by melt blending process at a variable weight percentage (wt%) of carbon: sisal fibre loading (20:10, 15:15, 10:20, and 5:25). MA-g-PP (MgP) as a compatibiliser was used to improve the dispersion of the fibres within the PP matrix. The composites were subjected to mechanical tests to optimize the fibre content of CF: SF. Incorporation of 20 wt% of CF and 10 wt% of SF with 5 wt% MgP resulted in higher mechanical performance of about 67.02 and 112% over that of PP/SF composite. Similarly, the impact strength was found to be optimum which enhanced to the tune of 39.62% as compared with PP/SF composites. Halpin Tsai model was used to compare the theoretical tensile modulus of PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites with experimental evaluated values. Fracture toughness parameters such as K IC (critical stress intensity factor) and G IC (critical strain energy release rate) are determined for PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites and compared by using single edge notch test. DSC study showed higher melting temperature (T m ) of PP/SF/CF/MgP composites as compared to PP revealing the enhancement in thermal stability. TGA/DTG study revealed the synergistic effect of the hybrid composite thus confirming the hybridisation effect of the system. DMA study showed that the hybridisation of CF and SF within the matrix polymer contributes to an increase in the storage modulus (Eʹ). Morphological observation by SEM confirmed that the carbon fibres and sisal fibres are well uniformly dispersed within the PP matrix, in the presence of MgP.

scholarly journals Mechanical properties of composite material laminates reinforced by woven and non-woven glass fibers

2020 ◽  
Vol 175 ◽  
pp. 12005 ◽  
Author(s):  
Amer Karnoub ◽  
Hajian Huang ◽  
Imad Antypas
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Glass Fiber ◽  
Mechanical Characteristics ◽  
Polyester Resin ◽  
Mechanical Performance ◽  
Glass Fibers ◽  
Mechanical Tests ◽  
Impact Behavior ◽  
The Impact

The purpose of this work is to study the mechanical characteristics in 3-point bending and in traction; static; and the impact behavior of three specimens of laminates made of glass fiber and polyester resin non-woven and woven, with the aim of using them in the repair of boat hulls and enhancing their value in the naval industry. Three types of laminates were developed by contact molding. These different specimens of laminates made of woven, non-woven and combined glass fiber (woven and non-woven) were subjected to mechanical tests (traction and 3-point bending). Analysis of the results of the tests carried out on these three types of laminate shows that one specimen stands out and gives higher mechanical performance than the othertwo.

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