scholarly journals Evaluating the Self-Sensing Ability of Cement Mortars Manufactured with Graphene Nanoplatelets, Virgin or Recycled Carbon Fibers through Piezoresistivity Tests

2018 ◽  
Vol 10 (11) ◽  
pp. 4013 ◽  
Author(s):  
Alberto Belli ◽  
Alessandra Mobili ◽  
Tiziano Bellezze ◽  
Francesca Tittarelli ◽  
Paulo Cachim
Keyword(s):  
Mechanical Properties ◽  
Electrical Resistivity ◽  
Uniaxial Compression ◽  
Carbon Fibers ◽  
Compressive Strain ◽  
The Self ◽  
Drying Process ◽  
Fractional Change ◽  
Graphene Nanoplatelet ◽  
Cement Mortars

This paper presents the resistivity and piezoresistivity behavior of cement-based mortars manufactured with graphene nanoplatelet filler (GNP), virgin carbon fibers (VCF) and recycled carbon fibers (RCF). GNP was added at 4% of the cement weight, whereas two percentages of carbon fibers were chosen, namely 0.05% and 0.2% of the total volume. The combined effect of both filler and fibers was also investigated. Mortars were studied in terms of their mechanical properties (under flexure and compression) and electrical resistivity. Mortars with the lowest electrical resistivity values were also subjected to cyclic uniaxial compression to evaluate the variations in electrical resistivity as a function of strain. The results obtained show that mortars have piezoresistive behavior only if they are subjected to a prior drying process. In addition, dry specimens exhibit a high piezoresistivity only when loaded with 0.2 vol.% of VCF and 0.4 wt.% of GNP plus 0.2 vol.% RCF, with a quite reversible relation between their fractional change in resistivity (FCR) and compressive strain.

Study on Structural Deformation and Performance of Polypropylene Spherulite Prepared by Uniaxial Compression Processing

2011 ◽  
Vol 175-176 ◽  
pp. 308-311
Author(s):  
Ming Li Jiao ◽  
Kai Yang ◽  
Wang Xi Zhang ◽  
Wei Pan
Keyword(s):  
Mechanical Properties ◽  
Tensile Properties ◽  
Uniaxial Compression ◽  
Small Deformation ◽  
Close Relation ◽  
Optical Microscope ◽  
The Self ◽  
Structural Deformation ◽  
Rapid Rise ◽  
And Performance

Mechanical properties have close relation with microstructure. Based on orientation of the molecule chain in fiber, they show a rapid increase in tensile properties. Nevertheless, block materials mainly gain rise of mechanical properties by blend or composite, it is hardly proposed on the self-reinforced materials by optimizing the microstructure. In this paper, a strengthening of PP was gained by uniaxial compression through small deformation of spherulite. A series of measurements were applied, including tensile test, polarizing optical microscope (POM) and differential scanning calorimeter (DSC). The results show that the tensile properties of polypropylene (PP) have a rapid rise. POM suggestes that the spherulite has deformed into ellipsoid even belt along the orientation of sample of PP, which plays an important role in self-reinforcing of PP. And the initial melt point displayed by DSC slightly decreases because of the partial ruptures of crystal phase.

scholarly journals Propiedades mecánicas de morteros de cemento con adiciones de fibras de carbono, nanotubos de carbono y grafeno = Mechanical properties of cement mortars with additions of carbon fibres, carbon nanotubes and graphene

2017 ◽  
Vol 3 (3) ◽  
pp. 12
Author(s):  
María Ursúa Goicoechea
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Carbon Fibers ◽  
Carbon Materials ◽  
Carbon Fibres ◽  
Cement Mortars ◽  
Different Types ◽  
Cement Matrices ◽  
Cement Compounds

El carbono es uno de los elementos más abundantes de la naturaleza. Su particular estructura hace que pueda tener hasta cinco tipos distintos de alótropos. Durante los últimos años se han producido grandes avances en el estudio de estos materiales de carbono. Las fibras de carbono (CF), los nanotubos de carbono (CNTs) y el grafeno y óxido de grafeno (GO), en función de su estructura y su escala, presentan unas propiedades notablemente diferenciadas. Este estudio pretende comparar y determinar los efectos de estas características en matrices de cemento. Las características de estos materiales son difíciles de transmitir de forma exacta a los compuestos de cemento y hormigones, principalmente por las dificultades que presentan los nanomateriales en su dispersión. Por ello, los datos obtenidos en distintos estudios muestran resultados muy variables. Sin embargo, se ha demostrado que, para mejoras medias, los nanomateriales resultan ser más eficientes.AbstractCarbon is one of the most abundant elements of nature. Its particular structure has to have up to five different types of allotropes. During the last years there have been great advances in the study of these carbon materials. Carbon fibers (CF), carbon nanotubes (CNT) and graphene and graphene oxide (GO), depending on their structure and scale, have remarkably different properties. This study aims to compare and determine the effects of these characteristics on cement matrices. The characteristics of these materials are difficult to transmit accurately to concrete and cement compounds, mainly due to the difficulties presented by nanomaterials in their dispersion. Therefore, the data obtained in different studies, results, very variable. However, it has been shown that, for average improvements, nanomaterials are more efficient.

scholarly journals Carbon-fiber-reinforced cement-based sensors

2007 ◽  
Vol 34 (3) ◽  
pp. 284-290 ◽  
Author(s):  
Rose Mary Chacko ◽  
Nemkumar Banthia ◽  
Aftab A Mufti
Keyword(s):  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Compressive Strain ◽  
Chloride Concentration ◽  
Petroleum Pitch ◽  
Fiber Reinforced ◽  
Reinforced Cement ◽  
Carbon Fiber Reinforced

The addition of carbon fibers has proved to be one of the most effective ways of improving the electrical conductivity of ordinary cement pastes. This implies that such materials can be used in strain, temperature, and chemical sensing. The present study was aimed at the development of such sensors. Inexpensive, petroleum-pitch-based, mesophase, high-modulus carbon fibers were used throughout. It was seen that materials with high conductivity could be obtained by reinforcing hydrated cement paste with carbon fibers. Electronic conduction was seen as the dominant mode over electrolytic conduction. Compared with strain, the influence of temperature on the electrical resistivity was found to be insignificant, implying a lack of need for temperature correction. Results also indicate that these sensors can be excellent crack detectors.Key words: carbon-fiber-reinforced cement-based composites, structural health monitoring, sensor, electrical resistivity, compressive strain, temperature, moisture content, chloride concentration, fiber volume fraction, water/cementitious ratio, cracking.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

Influence of graphitization conditions on structural and mechanical properties of polyacrylonitrile-based carbon fibers

2018 ◽  
pp. 46-59
Author(s):  
V. M. Samoilov ◽  
◽  
D. B. Verbets ◽  
I. A. Bubnenkov ◽  
N. N. Steparyova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers

scholarly journals Mechanical Properties of Hybrid Graphene Nanoplatelet-Nanosilica Filled Unidirectional Basalt Fibre Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1468
Author(s):  
Ummu Raihanah Hashim ◽  
Aidah Jumahat ◽  
Mohammad Jawaid
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Glass Fibre ◽  
Graphene Nanosheets ◽  
High Surface ◽  
High Surface Area ◽  
High Strength ◽  
Basalt Fibre ◽  
Graphene Nanoplatelet ◽  
Dispersion State

Basalt fibre (BF) is one of the most promising reinforcing natural materials for polymer composites that could replace the usage of glass fibre due to its comparable properties. The aim of adding nanofiller in polymer composites is to enhance the mechanical properties of the composites. In theory, the incorporation of high strength and stiffness nanofiller, namely graphene nanoplatelet (GNP), could create superior composite properties. However, the main challenges of incorporating this nanofiller are its poor dispersion state and aggregation in epoxy due to its high surface area and strong Van der Waals forces in between graphene sheets. In this study, we used one of the effective methods of functionalization to improve graphene’s dispersion and also introducing nanosilica filler to enhance platelets shear mechanism. The high dispersive silica nanospheres were introduced in the tactoids morphology of stacked graphene nanosheets in order to produce high shear forces during milling and exfoliate the GNP. The hybrid nanofiller modified epoxy polymers were impregnated into BF to evaluate the mechanical properties of the basalt fibre reinforced polymeric (BFRP) system under tensile, compression, flexural, and drop-weight impact tests. In response to the synergistic effect of zero-dimensional nanosilica and two-dimensional graphene nanoplatelets enhanced the mechanical properties of BFRP, especially in Basalt fibre + 0.2 wt% GNP/15 wt% NS (BF-H0.2) with the highest increment in modulus and strength to compare with unmodified BF. These findings also revealed that the incorporation of hybrid nanofiller contributed to the improvement in the mechanical properties of the composite. BF has huge potential as an alternative to the synthetic glass fibre for the fabrication of mechanical components and structures.

scholarly journals Development of Novel Lightweight Al-Rich Quinary Medium-Entropy Alloys with High Strength and Ductility

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4223
Author(s):  
Po-Sung Chen ◽  
Yu-Chin Liao ◽  
Yen-Ting Lin ◽  
Pei-Hua Tsai ◽  
Jason S. C. Jang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compressive Strain ◽  
High Strength ◽  
Fine Tuning ◽  
Face Centered Cubic ◽  
Transportation Industry ◽  
High Entropy ◽  
Good Potential ◽  
Face Centered

Most high-entropy alloys and medium-entropy alloys (MEAs) possess outstanding mechanical properties. In this study, a series of lightweight nonequiatomic Al50–Ti–Cr–Mn–V MEAs with a dual phase were produced through arc melting and drop casting. These cast alloys were composed of body-centered cubic and face-centered cubic phases. The density of all investigated MEAs was less than 5 g/cm3 in order to meet energy and transportation industry requirements. The effect of each element on the microstructure evolution and mechanical properties of these MEAs was investigated. All the MEAs demonstrated outstanding compressive strength, with no fractures observed after a compressive strain of 20%. Following the fine-tuning of the alloy composition, the Al50Ti20Cr10Mn15V5 MEA exhibited the most compressive strength (~1800 MPa) and ductility (~34%). A significant improvement in the mechanical compressive properties was achieved (strength of ~2000 MPa, strain of ~40%) after annealing (at 1000 °C for 0.5 h) and oil-quenching. With its extremely high specific compressive strength (452 MPa·g/cm3) and ductility, the lightweight Al50Ti20Cr10Mn15V5 MEA demonstrates good potential for energy or transportation applications in the future.

scholarly journals Mechanical properties of structures produced by 3D printing from composite materials

2019 ◽  
Vol 254 ◽  
pp. 01018
Author(s):  
František Bárnik ◽  
Milan Vaško ◽  
Milan Sága ◽  
Marián Handrik ◽  
Alžbeta Sapietová
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
3D Printing ◽  
Carbon Fibers ◽  
3D Printer

By 3D printing it is possible to create different structures with different fiber-laying directions. These structures can be created depending on the type of 3D printer and its software. The Mark Two printer allows printing Onyx, a material based on nylon in combination with microcarbon fibers. Onyx can be used alone or reinforced with kevlar, glass or carbon fibers. This article deals with 3D printing and evaluation of mechanical properties of printed samples.

Investigation of the Effect of the Length and Content of Carbon Fibers on the Properties of Polyphenylene Sulfide

2020 ◽  
Vol 869 ◽  
pp. 474-480
Author(s):  
Azamat L. Slonov ◽  
Ismel V. Musov ◽  
Elena V. Rzhevskaya ◽  
Azamat Zhansitov ◽  
Svetlana Yu. Khashirova
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Heat Resistance ◽  
Carbon Fibers ◽  
Filler Content ◽  
Sharp Decrease ◽  
Polyphenylene Sulfide ◽  
Average Particle ◽  
Melt Flow Rate ◽  
Particle Length

The article presents the results of a study of the effect of milled and chopped carbon fibers, with an average particle length of 0.2 and , respectively, on the mechanical properties of polyphenylene sulfide and its heat resistance. It was found that the introduction of carbon fibers leads to a significant decrease in the melt flow rate. It was shown that after a sharp decrease in impact strength at 10 % content of carbon fibers, its inverse improvement occurs with an increase in the filler content. Composites containing carbon fibers with length demonstrate higher impact strength. The introduction of a filler leads to a significant increase in the elastic modulus and strength of polyphenylene sulfide and its heat resistance.

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