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.

The Carbon Black Sonofication Effects on Vulcanisate Properties of Natural Rubber

2012 ◽  
Vol 626 ◽  
pp. 114-120 ◽  
Author(s):  
Mahendra Anggaravidya ◽  
Sudirman Sudirman ◽  
Bambang Soegijono ◽  
Emil Budianto ◽  
Martin Djamin
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Carbon Black ◽  
Natural Rubber ◽  
Carbon Black Particle ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Black Particle ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

The mechanical properties of natural rubber can be enhanced by the addition of carbon black. The mechanical properties change is highly affected by particle size and carbon black structure used. A modification of N660 carbon black was conducted in the research by sonoficating the carbon black for 3 and 5 hours (N600-M3; M5). The results of adding modified carbon black were characterised by Particle Size Analysis (PSA), Scanning Electron Microscopes - Energy Dispersive Spectrometry (SEM-EDS) and Thermogravimetric Analysis (TGA). The addition of modified carbon black shows bound rubber, thermal properties, and mechanical properties such as tensile strength, elongation at break and modulus 300% on the vulcanisate produced were increased from the vulcanisate that had been filled with N660 natural (N660-N). Keywords: natural rubber, carbon black, particle size, sonofication, characterisation

The Influence of Chrysotile Nanofibers Dispersion on the Physical and Mechanical Properties of the Cement Matrix

2021 ◽  
Vol 325 ◽  
pp. 21-27
Author(s):  
Grigory Ivanovich Yakovlev ◽  
Rostislav Drochytka ◽  
Valery Grakhov ◽  
Zarina S. Saidova ◽  
Irina Sergeevna Polyanskikh ◽  
...  
Keyword(s):  
Reference Sample ◽  
Physical And Mechanical Properties ◽  
Particle Size Analysis ◽  
Steam Treatment ◽  
Cement Matrix ◽  
Size Analysis ◽  
Fine Grained ◽  
Calcium Silicate Hydrates ◽  
Cement Binder ◽  
Positive Effect

The article describes the influence of chrysotile nanofibers dispersion introduction on the properties of the cement matrix. Comparison of the dispersion level of suspensions obtained using cavitation and ultrasonic processing methods is presented. The positive effect of chrysotile fibers application on the strength characteristics of the material has been confirmed. A 34% increase in the compressive strength of the samples was achieved on the 7th day of hardening, while on the 28th day it increased by 36% and with the steam treatment - by 38% compared to the reference sample. Laser particle size analysis confirmed the predominance of the nanosized component of chrysotile fibers in the suspension, which affected the structuring of the cement matrix. The results of the differential thermography, IR spectrometry, X-ray microanalysis and scanning electron microscopy of the samples are also presented. The analysis methods confirmed that introduction of chrysotile nanofibers suspension into the composition of a cement binder makes it possible to significantly vary the structure and morphology of new formations in fine-grained concrete. It also changes the quantitative and qualitative phase composition of the material with the formation of calcium silicate hydrates of lower basicity, leading to an increase in the strength of cement concrete.

scholarly journals Mechanical behavior of frozen soil improved with sulphoaluminate cement and its microscopic mechanism

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenhua Yin ◽  
Hu Zhang ◽  
Jianming Zhang ◽  
Mingtang Chai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Soil Improvement ◽  
Particle Size Analysis ◽  
Frozen Soil ◽  
Size Analysis ◽  
Permafrost Soil ◽  
Compression Tests ◽  
Microscopic Mechanism ◽  
Sulphoaluminate Cement

Abstract The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.

Synthesis of Alpha-Tricalcium Phosphate by Wet Reaction and Evaluation of Mechanical Properties

2012 ◽  
Vol 727-728 ◽  
pp. 1164-1169 ◽  
Author(s):  
Mônica Beatriz Thürmer ◽  
Rafaela Silveira Vieira ◽  
Juliana Machado Fernandes ◽  
Wilbur Trajano Guerin Coelho ◽  
Luis Alberto Santos
Keyword(s):  
Mechanical Properties ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Phosphate Cements

Calcium phosphate cements have bioactivity and osteoconductivity and can be molded and replace portions of bone tissue. The aim of this work was to study the obtainment of α-tricalcium phosphate, the main phase of calcium phosphate cement, by wet reaction from calcium nitrate and phosphoric acid. There are no reports about α-tricalcium phosphate obtained by this method. Two routes of chemical precipitation were evaluated and the use of two calcinations temperatures to obtain the phase of cement. The influence of calcination temperature on the mechanical properties of cement was evaluated. Cement samples were characterized by particle size analysis, X-ray diffraction, mechanical strength and scanning electron microscopy. The results demonstrate the strong influence of synthesis route on the crystalline phases of cement and the influence of concentration of reactants on the product of the reaction, as well as, on the mechanical properties of cement.

scholarly journals Waste Tire Particles and Gamma Radiation as Modifiers of the Mechanical Properties of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Eduardo Sadot Herrera-Sosa ◽  
Gonzalo Martínez-Barrera ◽  
Carlos Barrera-Díaz ◽  
Epifanio Cruz-Zaragoza
Keyword(s):  
Mechanical Properties ◽  
Gamma Radiation ◽  
Chemical Properties ◽  
Plain Concrete ◽  
Cement Matrix ◽  
Portland Cement Concrete ◽  
High Concentration ◽  
Good Tool ◽  
Waste Tire ◽  
Physical And Chemical

In polymer reinforced concrete, the Young’s modulus of both polymers and cement matrix is responsible for the detrimental properties of the concrete, including compressive and tensile strength, as well as stiffness. A novel methodology for solving such problems is based on use of ionizing radiation, which has proven to be a good tool for improvement on physical and chemical properties of several materials including polymers, ceramics, and composites. In this work, particles of 0.85 mm and 2.80 mm obtained from waste tire were submitted at 250 kGy of gamma radiation in order to modify their physicochemical properties and then used as reinforcement in Portland cement concrete for improving mechanical properties. The results show diminution on mechanical properties in both kinds of concrete without (or with) irradiated tire particles with respect to plain concrete. Nevertheless such diminutions (from 2 to 16%) are compensated with the use of high concentration of waste tire particles (30%), which ensures that the concrete will not significantly increase the cost.

scholarly journals Soil Attributes Using Different Agricultural Use Systems in the Rio Grande do Norte Semiarid, Brazil

2018 ◽  
Vol 10 (11) ◽  
pp. 190
Author(s):  
Ana Karenina Fernandes de Sousa Ribeiro ◽  
Jeane Cruz Portela ◽  
Rafael Oliveira Batista ◽  
Carolina Malala Martins Souza ◽  
Joseane Dunga da Costa ◽  
...  
Keyword(s):  
High Salinity ◽  
Clay Fraction ◽  
Particle Size Analysis ◽  
Semiarid Region ◽  
Size Analysis ◽  
Plasticity Limit ◽  
Physical Attributes ◽  
Agricultural Use ◽  
Chemical Attributes ◽  
Physical And Chemical

The semiarid region is extremely fragile to anthropogenic actions. Thus, the objective of this study is to evaluate the physical and chemical attributes of soils with different agricultural uses. The research was carried out in the municipality of Governador Dix-Sept Rosado. Fertility and physical analyses were performed. The results were interpreted by multivariate analysis. The soils that presented a eutrophic character were influenced by lithology. In the Cambissolo (Haplustepts), there was an increase in the limits of liquidity and plasticity due to the increase of the clay fraction and total organic carbon. By the particle size analysis, the profiles presented variations in textural classes. We concluded that the physical attributes moisture, liquidity limit, plasticity limit, clay plasticity index, thin sand and the chemical attributes pH, (H + Al), V and PST were the most sensitive for the distinction of environments. The studied areas presented acidity reactions to alkalinity with presence of Al3+, (H + Al) and high salinity.

Pressure assisted sintering of Al2O3–Y2O3 glass microspheres: sintering conditions, grain size, and mechanical properties of sintered ceramics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anna Prnová ◽  
Jana Valúchová ◽  
Monika Michálková ◽  
Beáta Pecušová ◽  
Milan Parchovianský ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Hot Pressing ◽  
Pechini Method ◽  
Sol Gel ◽  
Applied Pressure ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Glass Microspheres ◽  
Amorphous Powders

Abstract Glass microspheres with yttria-alumina eutectic composition (76.8 mol % Al2O3 and 23.2 mol % Y2O3) were prepared by sol-gel Pechini method and flame synthesis with or without subsequent milling. Prepared amorphous powders were studied by X-ray powder diffraction (XRD), particle size analysis (PSA), scanning electron microscopy (SEM) and differential thermal analysis (DTA). Hot pressing (HP), rapid hot pressing (RHP) and spark plasma sintering (SPS) were used to sinter amorphous precursor powders at 1600 °C without holding time (0 min). The preparation process including milling step resulted in amorphous powders with narrower particle size distribution and smaller particle size. All applied pressure assisted sintering techniques resulted in dense bulk samples with fine grained microstructure consisting of irregular α-Al2O3 and Y3Al5O12 (YAG) grains. Milling was beneficial in terms of final microstructure refinement and mechanical properties of sintered materials. A material with the Vickers hardness of HV = (17.1 ± 0.3) GPa and indentation fracture resistance of (4.2 ± 0.2) MPa.m1/2 was prepared from the powder milled for 12 h.

scholarly journals Effects of Tailings Gradation on Rheological Properties of Filling Slurry

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Bingwen Wang ◽  
Tingyong Xiong ◽  
Lijing Gao ◽  
Yuepeng Chai ◽  
Xiangyu Cui ◽  
...  
Keyword(s):  
Particle Size ◽  
System Design ◽  
Rheological Properties ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Analysis Software ◽  
Key Technology ◽  
Fine Grained ◽  
Viscosity Coefficients ◽  
Filling System

The key technology in filling mining is the gravity transportation of high-density slurries, and the filling system design is a significant part of this technology. The filling effect depends on the fluidity of the filling slurry. To investigate the influence of the gradation of tailings on the rheological properties of the filling slurry, this study uses particle size analysis to prepare three types of tailings: powder-, relatively fine-, and fine-grained tailings, which are then mixed in different proportions. The rheological properties of the resulting filling slurries are tested; the viscosity coefficients and yield stresses of the slurries are obtained using the analysis software provided with the MCR102 advanced rheometer that is used to measure the rheological properties of the slurries. The experimental results demonstrate that there is no absolute relationship between the rheological properties of the slurry and the size of the tailings particles, but the rheological properties are related to the gradation of tailings. Lubricating effect is weakened with an insufficient content of powder-grained particles in the tailings. On the contrary, when the content of powder-grained particles in the tailings is too high, the viscous substances in the slurry increase. Both of these conditions can increase the friction loss of the slurry.

The Influence of Aggregates on the Properties of Concrete

2014 ◽  
Vol 1000 ◽  
pp. 277-280 ◽  
Author(s):  
Pavel Šiler ◽  
Ondřej Bezděk ◽  
Iva Kolářová ◽  
Eva Bartoníčková ◽  
Tomáš Opravil ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Particle Size Analysis ◽  
Hydration Process ◽  
Silica Sand ◽  
Size Analysis ◽  
Isoperibolic Calorimetry

This work is focused on the influence of aggregates on the mechanical properties of concrete and hydration process. The flexural strength and compressive strength were observed after 1, 7 and 28 days of curing. The process of hydration was monitored using isoperibolic calorimetry. Laser particle size analysis of aggregates was also performed. The following materials were used: Portland cement CEM I 42,5 R-Sc, finely ground silica sand, calcinated bauxite, fine, medium and rough testing sand (defined in ČSN EN 196-1).

Comparison of Reinforcing Efficiency between Calcium Carbonate/Carbon Black and Calcium Carbonate/Silica Hybrid Filled Natural Rubber Composites

2018 ◽  
Vol 382 ◽  
pp. 94-98 ◽  
Author(s):  
Sarawut Prasertsri ◽  
Chaiwute Vudjung ◽  
Wunchai Inthisaeng ◽  
Sansanee Srichan ◽  
Kanchana Sapprasert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Hybrid System ◽  
Hybrid Composites ◽  
Strength Increase ◽  
Hybrid Filler ◽  
Carbonate Carbon ◽  
Cure Time

The present research aimed to develop natural rubber (NR) hybrid composites reinforced with calcium carbonate/carbon black (CC/CB) and calcium carbonate/silica (CC/SC). The influence of CC/CB and CC/SC with various filler ratios (120/0, 90/5, 60/10, 30/15 and 0/20) on cure characteristics and mechanical properties of the vulcanizates was investigated and their reinforcing efficiency was compared. It has been found that incorporation of CB in the hybrid filler decreases the scorch time and cure time but increases crosslink density, whereas the incorporation of silica showed cure retardation. As CB or SC content increases, stiffness, tensile strength and tear strength increase, while elongation at break and compression set decrease. Scanning electron microscopy studies also reveal poor filler dispersion and poor adhesion between filler particles and matrix in the vulcanizates with increasing in CC content in a weight filler ratio which causes inferior mechanical properties. Incorporation of CB or SC content enhanced the mechanical properties of the vulcanizates, where CC/CB hybrid system exhibited higher reinforcing efficiency compared with CC/SC hybrid system.

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