scholarly journals PLASMA MODIFICATION OF MICROFIBERS - APPLICATION TO LIGHTWEIGHT CEMENT COMPOSITE CONTAINING RECYCLED CONCRETE

2021 ◽  
Vol 30 ◽  
pp. 7-11
Author(s):  
Jakub Ďureje ◽  
Zdeněk Prošek ◽  
Jan Trejbal ◽  
Pavel Tesárek ◽  
Štěpán Potocký
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Oxygen Plasma ◽  
Cement Composite ◽  
Recycled Concrete ◽  
Plasma Modification ◽  
Cement Matrix ◽  
Foaming Agent ◽  
Cementitious Matrix

The article deals with the optimalization of composition for reinforced lightweight cement composite containing micronized recycled concrete, which will be used to produce masonry blocks. The composite material is reinforced with polypropylene microfibers. To increase the cohesion between the fibers and the cementitious matrix, the optimal modification using oxygen plasma was chosen. Furthermore, a suitable foaming agent was chosen to lighten the cement matrix. A suitable ratio of cement and micronized recycled concrete was determined. Finally, a cement composite was made from the optimized components. The mechanical properties of this composite were tested. The resulting mechanical properties of the lightweight samples were compared with the non-light samples.

Influence of Oxygen Plasma Modification Carbon Fiber on Flexural Strength and Hydrothermal Properties of CF/PES Composite

2014 ◽  
Vol 926-930 ◽  
pp. 141-144
Author(s):  
Xu Cui ◽  
Yan Jiao Huang ◽  
Yu Gao ◽  
Shuo Wang
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Retention Rate ◽  
Test Method ◽  
Plasma Modification ◽  
Resin Matrix ◽  
Strength Retention

In this paper, low temperature oxygen plasma treatment method was adopted to process the carbon fiber surface. Flexural Strength test method was utilized to represent f composite material flexural strength. This paper observed flexural failure morphology of composite material by aid of SEM, then it compared the mechanical property, hygroscopicitiy and flexural strength retention rate of composite material before and after the plasma treatment. Results showed that the optimum treatment conditions of carbon fiber were 300W treatment power and 15-minute treatment time. Under the condition, the highest flexural strength value be increased by 19.55%.Saturated bibulous is low and bibulous rate is slow, flexural strength retention rate is 94.9%. And at the same time PES-C resin matrix can be strengthened, which will further improve the mechanical properties of composite materials.

scholarly journals PLASMA MODIFICATION OF POLYVINYL ALCOHOL MICROFIBERS TO IMPROVE COHESION WITH CEMENT MATRIX

2019 ◽  
Vol 21 ◽  
pp. 1-4
Author(s):  
Jakub Ďureje ◽  
Zdeněk Prošek ◽  
Jan Trejbal ◽  
Pavel Tesárek
Keyword(s):  
Composite Material ◽  
Polyvinyl Alcohol ◽  
Hydrogen Plasma ◽  
Fiber Surface ◽  
Sem Analysis ◽  
Plasma Modification ◽  
Cement Matrix ◽  
Compression Tests ◽  
Wettability Measurement ◽  
Reference Samples

The article describes plasma modifications of the surface of polyvinyl alcohol (PVA) microfibers using oxygen and hydrogen plasma in order to improve the properties of the composite material containing modified microfibers, cement and recyclate. Five different modification times 30, 60, 120, 240 and 480 seconds were applied. Changes on fiber surface were detected by SEM analysis, packed cell wettability measurement, and weight loss during modification. The selected durations of plasma treatment were chosen to produce test samples on which the modulus of elasticity was continuously measured and then bending and compression tests were performed. The measured values were compared with the reference samples. Oxygen modified fibers behavior is more hydrophilic compare with reference fibers, but hydrogen modified fibres behave more hydrophobic than reference fibers.

scholarly journals Effect of Carbon Nanotube Aqueous Dispersion Quality on Mechanical Properties of Cement Composite

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Larisa I. Nasibulina ◽  
Ilya V. Anoshkin ◽  
Albert G. Nasibulin ◽  
Andrzej Cwirzen ◽  
Vesa Penttala ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Chemical Interaction ◽  
Mechanical Test ◽  
Aqueous Dispersion ◽  
Fold Increase ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Pastes ◽  
Marginal Improvement

An effect of the quality of carbon nanotube (CNT) dispersions added to cement on paste mechanical properties has been studied. High-quality dispersions of few-walled CNT (FWCNTs) were produced in two steps. First, FWCNTs were functionalized in a mixture of nitric and sulfuric acids (70 wt.% and 96 wt.%, resp.) at80∘C. Second, functionalized FWCNTs were washed out by acetone to remove carboxylated carbonaceous fragments (CCFs) formed during CNT oxidation. Mechanical test results showed 2-fold increase in the compressive strength of the cement paste prepared from the dispersion of acetone-washed functionalized FWCNTs, which is believed to occur due to the chemical interaction between cement matrix and functional groups (–COOH and –OH). Utilisation of unwashed FWCNTs led to a marginal improvement of mechanical properties of the cement pastes, whereas surfactant-treated functionalized FWCNT dispersions only worsened the mechanical properties.

scholarly journals MECHANICAL PROPERTIES OF CEMENT COMPOSITE CONTAINING RECYCLED CONCRETE AND ALKALI ACTIVATED BLAST FURNACE SLAG

2020 ◽  
Vol 26 ◽  
pp. 30-33
Author(s):  
Jan Horych ◽  
Pavel Tesárek ◽  
Zdeněk Prošek
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Cement Composite ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Cement Composites ◽  
Positive Effect ◽  
Furnace Slag ◽  
Alkali Activated

Recycling of materials is very popular and very important in these days. Finding the new ways to process and use these materials is a key to get rid of a lot of construction waste. The amount of landfilling needs to be reduced. This study observes mechanical properties of the cement composites containing recycled concrete powder and alkali-activated blast furnace slag processed on a high- peed mill as a potential binder replacement up to the 60 wt. %. These materials have a positive effect on hydration process, increase flexural strength. It can reduce compressive strength loss when an amount of cement in the mixture is reduced.

scholarly journals Interface Bond Characterization between Fiber and Cementitious Matrix

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Won-Chang Choi ◽  
Seok-Joon Jang ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Fiber Type ◽  
Polypropylene Fiber ◽  
Interfacial Properties ◽  
Design Parameters ◽  
Cement Matrix ◽  
Cementitious Matrix ◽  
Pull Out ◽  
Binder Ratio

The use of high performance composite fibers allows for the improvement of the mechanical properties of cement composites. Previous research results indicate that the mechanical properties of such composites are determined predominantly by the interface properties between the fiber and cementitious matrix. Many researchers have conducted single-fiber pull-out tests using cementitious composites to quantify the interfacial properties between the fiber and cement matrix. This paper aims to establish a design methodology that employs coefficients to represent the design parameters for the interfacial properties for three types of fibers: carbon fiber, polypropylene fiber, and twisted wire strand steel cord. The parameters for each type of fiber include the water-to-binder ratio and fiber embedment length. The adopted equation used for the numerical analysis was calibrated using experimental data, and design coefficients are proposed accordingly. The developed models could be validated successfully, and the pull-out characteristics of each fiber type are presented.

scholarly journals Modification of Cement Matrix with Complex Additive Based on Chrysotyl Nanofibers and Carbon Black

2021 ◽  
Vol 11 (15) ◽  
pp. 6943
Author(s):  
Zarina Saidova ◽  
Grigory Yakovlev ◽  
Olga Smirnova ◽  
Anastasiya Gordina ◽  
Natalia Kuzmina
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Cement Composite ◽  
Particle Size Analysis ◽  
Cement Matrix ◽  
Size Analysis ◽  
Strength Increase ◽  
Fine Grained ◽  
Complex Additive ◽  
Physical And Chemical

This paper presents the results of studying the properties of cement-based composites modified with a complex additive based on chrysotile nanofibers and carbon black. The optimal composition of complex additive was stated due to the particle size analysis of suspensions with different chrysotile to carbon black ratios and the mechanical properties study of the fine-grained concrete modified with the complex additive. It was found that the addition of chrysotile in the amount of 0.05% of cement mass together with carbon black in the amount of 0.01% of cement mass leads to a 31.9% compression strength increase of cement composite and a 26.7% flexural strength increase. In order to explain the change in the mechanical properties of the material, physical and chemical testing methods were used including IR-spectral analysis, differential thermal analysis, energy dispersive X-ray analysis as well as the study of the microstructure of the samples modified with the complex additive. They revealed the formation of durable hydration products including thaumasite and calcium silicate hydrates of lower basicity that form a dense structure of cement matrix, increasing the physical and mechanical characteristics of cement-based composites.

scholarly journals USE OF FINELY GROUND RECYCLED CONCRETE FOR IMPROVEMENT OF INTERFACIAL ADHESION IN FIBER-REINFORCED CEMENTITIOUS COMPOSITES

2019 ◽  
Vol 21 ◽  
pp. 5-9
Author(s):  
Radim Hlůžek ◽  
Jan Trejbal
Keyword(s):  
Plasma Treatment ◽  
Interfacial Adhesion ◽  
Oxygen Plasma ◽  
Recycled Concrete ◽  
Cement Matrix ◽  
Oxygen Plasma Treatment ◽  
Fiber Types ◽  
Pull Out ◽  
The Matrix ◽  
Fiber Reinforced Cementitious Composites

This paper deals with an improvement and an assessment of a polymeric macro-fibers adhesion to the cement matrix. For this purpose, two approaches were employed – (i) roughening of fibers using a plasma treatment and (ii) an addition of finely ground recycled concrete (amount 30 wt. %) to the matrix ensuring the roughness of interfacial zones. Polyethylene terephthalate (PET) and polypropylene (PP) fibers, both ca. 0.3mm in a diameter, were used. These were surface roughened using a cold oxygen plasma treatment and then observed by means of the scanning electron microscopy. Consequently, pull-out tests of an individual fiber embedded 25mm in the matrix were performed, while the force needed for fiber pullout was recorded. Results have shown that plasma treated fibers reached on a better adhesion with the matrix by up to ca. 5% (PET) and 20% (PP), if compared to reference fibers. When recycled concrete was used, the adhesion increased further by about 5–10% for both fiber types.

Study of the pull-out test of multifilament yarns embedded in cementitious matrix

2020 ◽  
Vol 55 (2) ◽  
pp. 169-185
Author(s):  
Anne-Claire Slama ◽  
Jean-Louis Gallias ◽  
Bruno Fiorio
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Composite ◽  
Maximum Load ◽  
Variable Number ◽  
Tensile Behaviour ◽  
Cementitious Matrix ◽  
Pull Out ◽  
The Matrix ◽  
Multifilament Yarns

In order to understand the impregnation mechanism of a yarn by a cementitious matrix and its influence on the mechanical properties of a yarn/cement composite, pull-out tests have been performed on samples of yarn/cement. Two embedded lengths for the yarn and different rheological and mechanical properties for the matrix were tested. Two pull-out modes were distinguished according to the compressive strength of matrices. For matrices with a compressive strength between 60 and 70 MPa the pull-out mode is characterized by a behaviour close to the tensile behaviour of the yarn, with maximum load values reaching approximately 60% of the tensile maximum load because of filaments damages. For matrices with compressive strength inferior to 60 MPa, the pull-out mode exhibits a residual phase linked to a slippage and an extraction of a variable number of filaments, with lower maximum load values than the first pull-out mode. After pull-out test, for some samples with filaments extraction, an innovative method based on a double impregnation with resin enables to visualize the yarn/matrix interface and identify the level of impregnation of the filaments by using confocal microscopy. It is concluded that this level of impregnation has a direct influence on the mechanical behaviour of the embedded yarn, except for the slippage and extraction phase, but the rheological properties of the matrix has no significant influence on this impregnation.

scholarly journals The Effect of Interfacial Transition Zone Properties on the Elastic Properties of Cementitious Nanocomposite Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Ala G. Abu Taqa ◽  
Rashid K. Abu Al-Rub ◽  
Ahmed Senouci ◽  
Nasser Al-Nuaimi ◽  
Khaldoon A. Bani-Hani
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Elastic Modulus ◽  
Transition Zone ◽  
Parametric Study ◽  
Nanocomposite Materials ◽  
Interfacial Transition Zone ◽  
Cement Matrix ◽  
Reinforced Cement ◽  
Cohesive Surface

A parametric study was conducted to explore the effect of the interfacial transition zone (ITZ or interphase) on the overall elastic modulus of the CNT-reinforced cement. The effect of the ITZ properties on the elastic modulus of the CNT-reinforced cement was investigated using a four-phase axisymmetric model consisting of a single CNT aligned at the center of composite unit cell, an interface, an ITZ (or interphase), and a cement matrix. The CNT and cement matrix were assumed fully elastic while the interface was modeled using a cohesive surface framework. The width and mechanical properties of the ITZ and the interface were found to affect significantly the elastic modulus and the behavior of the composite material.

Influence of Oxygen Plasma Modification Carbon Fiber on the Hydrothermal Property of CF/PES-C Composite

2014 ◽  
Vol 513-517 ◽  
pp. 51-55
Author(s):  
Xu Cui ◽  
Gui Long Liu ◽  
Chun Lu ◽  
Shuo Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Mechanical Strength ◽  
Water Absorption ◽  
Oxygen Plasma ◽  
Retention Rate ◽  
Plasma Modification ◽  
Resin Matrix ◽  
Before And After ◽  
Resin Matrix Composite

In this paper, the CF/PSE-C composite is studied and tested: its characteristics of water absorption before and after the treatment of plasma are determined; the mechanical properties of the composite after water absorption are analyzed and its retention rate of mechanical strength after the absorption is compared. Results show that the water absorption of CF/PES-C composite which has been treated by plasma for 15 minutes is lower and the speed of absorption is slower while retention rate of mechanical strength after absorption is high. The CF/PFS-C resin matrix composite produced after plasma treatment is thicker and the interface pore between CF and PES-C resin matrix becomes smaller, which improves the composites moisture and heat resistance.

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