scholarly journals Refractory concrete based on alumina cement out of low-grade raw materials

Author(s):  
R. M. Vorozhbiyan ◽  
G. N. Shabanova ◽  
A. N. Korogodskaya

The development results are given for the refractory concretes based on the modifed alumina cement with the using of the chemical industry wastes. The quantitative ratio for the near-gravity materials, the technological factors' influence on the concrete strength, the dependence of its strength properties on the flling aggregate's kind and its curing conditions were defned in the article. It was shown that the physical and mechanical properties of the developed concretes are as good as those of the commercial concretes. According to all technical characteristics this kind of production can be introduced for using as the high temperature vessels' lining material.Ill.6. Ref. 11. Tab. 4.

2018 ◽  
Vol 8 (1) ◽  
pp. 132-138
Author(s):  
Виктор Бурындин ◽  
Viktor Buryndin ◽  
Лариса Бельчинская ◽  
Larisa Belchinskaya ◽  
Андрей Савиновских ◽  
...  

The possibility of obtaining wood and plant plastics without a binder (WP-WB) in the presence of a catalyst of man-ganese-containing sodium vanadomolybdophosphate has been investigated. The use of this catalyst makes it possible to reduce the temperature of hot pressing in closed molds from 1,800°C to 1,600°C. The fractional composition of the initial press raw material influences physical and mechanical properties of WP-WB. Higher values of the plastic properties are obtained by using a 0.7 mm fraction, which is associated with an increased specific surface area of the particles compared to 1.3 mm particles. The results has showed that the samples obtained by using the catalyst have increase in strength properties (flexural strength, flexural modulus, hardness) at lower pressing temperature, but reduction of water resistance performance has been observed . This is explained by the increase in the content of functional groups when using a catalyst. The process of obtaining plastic can be broken down into two successive stages: the first is hydrothermal destruction of lignin-carbohydrate complex (initial moisture of the press raw material is 12%, the temperature of hot pressing in closed molds is 160 ... .180 ° C) and partial chemical activation of lignin as a result of hydrogen peroxide and catalyst application; the second stage - formation of plastic with the formation of a network structure due to the formed functional groups. It is established that the values of physical and mechanical properties of WP-WB are higher than those of plastic obtained on the basis of plant raw materials (PP-WB). This can be explained by the fact that lignin of coniferous species has the guaiacylpropane structure, while plant raw material has a hydroxyphenylpropane structure


2018 ◽  
Vol 143 ◽  
pp. 02009 ◽  
Author(s):  
Andrey Stolboushkin ◽  
Danil Akst ◽  
Oksana Fomina ◽  
Aleksandr Ivanov

The given paper investigates the influence of manganese-containing wastes on bulk coloring and physical and mechanical properties of wall ceramic materials with matrix structure. Conventional research methods to study physical and mechanical properties of ceramic specimens were used in the present study. The structure and phase state of decorative ceramic materials were investigated by means of physical-chemical analysis. Authors suggested the model to form coloring layer in ceramic matrix composites based on argillaceous raw materials and coloring pigment. Macrostructure was studied on ceramic samples manufactured according to the developed method from clay loam of moderate plasticity and wastes of manganese mining. The paper provides results of pilot testing on production of colored ceramic brick. It was found that incorporation of coloring component does not decrease strength properties of ceramic matrix materials. Authors defined the palette and color code for decorative ceramic specimens manufactured with different content of coloring component of manganese mining wastes according to RGB color codes chart.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1382
Author(s):  
Małgorzata Gołaszewska ◽  
Jacek Gołaszewski ◽  
Grzegorz Cygan ◽  
Jerzy Bochen

The article presented the analysis of the impact that various kinds of technological inaccuracies have on the properties of fresh masonry mortars and plasters. Analyzed were the inaccuracies in dosing of mortar components, namely, water, lime, and air-entraining plasticizing admixture (APA) (±10% of mass), and the effect of variable technological conditions, namely, different mixing intensity (fast, slow, normal) and temperature (5 °C, 20 °C, and 35 °C) during first 72 h after mixing. The impact of differences in the properties of cement and aerial (hydrated) lime originating from different manufacturers was also analyzed. The impact of these factors was determined for consistency, density, air content, compressive, and flexural strength. The sensitivity to changes in the analyzed properties was determined by the coefficient of variation. Changes in the dosing of constituents, mixing speed, and temperature adversely affected strength properties. For mortars with APA, these changes exceeded 20% and reached 40%. The greatest impact was evident in the consistency, especially with an excess of APA, where changes ranged from 6% to 80%. The results showed greater resistance of cement-lime mortars to changing selected technological conditions and errors in measuring the amount of ingredients than mortars with air-entraining plasticizing admixture (APA).


2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.


2021 ◽  
Vol 20 (1) ◽  
pp. 37-51
Author(s):  
Kubilay Akçaözoğlu ◽  
◽  
Adem Kıllı ◽  

In this study, the effect of curing conditions on the mechanical properties of slurry infiltrated fiber reinforced concrete (SIFCON) was investigated. For this purpose, SIFCON samples containing 4% and 8% steel fiber with two different aspect ratios were produced. The samples were subjected to three different curing types, namely standard, dry and accelerated curing methods. Ultrasonic wave velocity, flexural strength, fracture toughness, compressive strength, impact resistance and capillary water absorption tests were performed on the samples. The highest flexural strength was found to be achieved in the samples with an aspect ratio of 55 and a content of 8% steel fiber. The most suitable curing method was determined as the standard curing method and the best flexural strength was achieved at the rate of 8%. According to the test results, the best strength properties were achieved in the samples exposed to the standard curing method. In addition, the samples exposed to the accelerated curing method showed satisfactory values. The accelerated curing method can be used as an alternative in SIFCON production especially in applications requiring mass production.


2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Dendi Prayoga ◽  
. Dirhamsyah ◽  
. Nurhaida

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30%  and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with  pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon  with composition a ratio of  rice husk 50%: sengon 50% , 16% adhesive content  16%, with density value of  0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Ridho Pratama ◽  
M Dirhamsyah ◽  
. Nurhaida

This study aims to examine the physical and mechanical properties of gypsum board from Acacia mangium Willd wood waste based on gypsum content and wood powder size. This study refers to the JIS A 5417-1992 standard. This research were conducted at Wood Work Shop laboratory for the preparation of raw materials, Wood Technology laboratory Faculty of Forestry for board making and testing the physical properties of gypsum boards, and  PT. Duta Pertiwi Nusantara laboratory to test the mechanical properties of the gypsum board. The material used is  A. mangium W. Wood powder, gypsum flour, water and borax. The study uses Factorial Completely Randomized Design (CRD) with two factors, namely factor A (gypsum content) which consists of gypsum content of 400%, 500% and 600% of the weight of A. mangium W. wood powder, and factors B (wood powder size) consists of 20 mesh passes 40 mesh retained and 40 mesh passes 60 mesh retained. The results showed that the density (600% gypsum content of 40 and 60 mesh retained wood powder size), moisture content, thickness swelling, MOE (600% gypsum content of 40 and 60 mesh retained wood powder size) fulfill JIS A5417-1992 standard. The best gypsum board is gypsum board with gypsum content of 600% with a wood powder size is 40 mesh.Keyword: Acacia mangium, gypsum board, gypsum content, wood powder size.


2020 ◽  
Vol 992 ◽  
pp. 253-258
Author(s):  
M.P. Lebedev ◽  
V.N. Tagrov ◽  
E.S. Lukin

The article deals with the manufacture of modern structural ceramic materials from clay and loam deposits of the Republic of Sakha (Yakutia). The importance and relevance of the development of the production of building materials from local raw materials is emphasized, since this will certainly affect the effectiveness of the construction complex as a whole. The successful development of the construction complex is capable of not only stimulating growth in all sectors of the economy, but also contributes to solving the most pressing social problems. Today, Yakutia has huge reserves of mineral raw materials for the production of a wide range of building materials and products. Of practical interest are wall materials made from clay soils. Given the features of the region’s raw material base, this work focuses on additional processing of traditional material. Controlling the complex physicochemical and structural-mechanical transformations that occur during heat treatment, a methodology has been developed for creating a composite material that will allow competitive innovative materials with enhanced strength properties to be produced with a reinforcing element with a glassy phase matrix of mullite crystals. The fabricated samples have a wide range of physical and mechanical properties and allow using it as a high-quality structural building ceramics, as well as industrial floor technical tile.


Author(s):  
A. A. Ponomarenko ◽  
I. V. Kormina

The influence of the deflocculant of the Russian company Polyplast-UralSib LLC on the properties of the groove and selfdissolving masses for lining the working surfaces of thermal units is considered. It was found that when a deflocculant is introduced into the refractory concrete masses in an amount of 2.0 wt. % satisfactory workability of the mass and the required physical and mechanical properties of concrete after firing at 1000 and 1400 °C are ensured compared to the introduction of imported deflocculants ADW / ADS and SioxX / Siox-Quick. It is shown that the gutter concrete obtained using the Russian deflocculant has higher strength than concrete with an imported deflocculant, including 0.5 wt. % ADW1 and 0.5 wt. % ADS3. Petrographic analysis revealed equal resistance of the trench concrete to the effects of blast furnace slag when using Russian additives and imported SioxX and Siox-Quick in the amount of 2,0 and 0,5 wt. % as deflocculants respectively. Ill. 1. Ref. 26. Tab. 2.


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