scholarly journals The mechanochemical treatment of the building materials

2015 ◽  
Vol 3 ◽  
pp. 22-25
Author(s):  
Gurinovich L.S. ◽  
Usov B.A.

The article is devoted to the obtaining of activated additives and cements, to improve the quality or the obtaining of new building materials using rotary pulsation apparatus (RPA). It also considers the efficiency of the RPA. As a result the works were obtained in different activated in the RPA chemical additives for concrete from sparingly soluble in water products established distinctive features of the solutions of plasticizers and complex additives, treated in the RPA. It is shown that the preparation of concrete with the use of activated materials in the RPA to reduce labor costs in the manufacture of a product, reduce the consumption of cement, flow additives, plasticizers, water consumption, accelerate hardening and to increase strength and durability of concrete. It is noted that when changing the amount of additives in the solution and time of mechanochemical treatment, it becomes possible to control the technological parameters of concrete mixture (mobility, stiffness) and thus increase the strength of concrete. When the content of additives PDO 0.15% and activation time of 5 minutes the increase in strength was 60 kg/cm2. With increasing number of activated additives up to 1 % strength in concrete was increased, while the introduction of the same amount of additives without activation promoted a decrease in strength below without additional values.

Author(s):  
O.Yu. Erenkov ◽  
◽  
I.Ya. Lopushanskiy ◽  
E.V. Yavorskaya ◽  
◽  
...  

2018 ◽  
Vol 41 ◽  
pp. 01042
Author(s):  
Vasilii Murko ◽  
Veniamin Khyamyalyainen ◽  
Marina Baranova

Effective utilization of ash-and-slag waste generated by coalfired power plants can help significantly to reduce the negative impact on the environment and improve their economic performance. Studies have been made of the mineralogical composition of ash-and-slag wastes obtained after the combustion of water-coal fuel based on fine-dispersed coal-washing waste (filter cake) in a specially designed boiler with a vortex combustion system. The possibility of effective use of ash-and-slag wastes for the production of building materials, primarily mortar mixes, widely used for mining works on mine openings, laying the worked out space, etc. (high content of silicon oxide and aluminum oxide is combined with a low carbon content in other words a negligible unburned carbon loss). The optimum percentage ratio of the initial components of the filling mixture based on ash-and-slag wastes and crushed rock (granulated slag) has been established. The results of experimental tests of hardening tabs on the strength under uniaxial compression are presented. It has been established that a sample containing 18% of ash-and-slag wastes, 33% of a granulated slag and 19% of cement, corresponds to the required technological parameters for the strength and cement content.


2020 ◽  
pp. 103-110
Author(s):  
Larysa Sablii ◽  
Oleksandr Obodovych ◽  
Vitalii Sydorenko ◽  
Tamila Sheyko

This paper presents the results of studies of isolation lignin and hemicelluloses efficiency during the pre-treatment of wheat straw for hydrolysis in a rotary-pulsation apparatus. The pre-treatment of lignocellulosic raw materials for hydrolysis is a necessary step in the second-generation bioethanol production technology. The lignocellulose complex is destroyed during this process, and this allows hydrolytic enzymes access to the surface of cellulose fibers. The pre-treatment is the most energy-consuming stage in bioethanol production technology, since it usually occurs at high temperature and pressure for a significant time. One of the ways to improve the efficiency of this process is the use of energy-efficient equipment that allows intensifying heat and mass transfer. An example of such equipment is a rotary-pulsation apparatus, which are effective devices in stirring, homogenization, dispersion technologies, etc. The treatment of wheat straw in a rotary-pulsation apparatus was carried out under atmospheric pressure without external heat supply at solid/water ratios of 1:10 and 1:5 in the presence of alkali. It was determined that the treatment of the water dispersion of straw at ratio of 1:10 due to the energy dissipation during 70 minutes leads to the release of 42 % of lignin and 25.76 % of easily hydrolyzed polysaccharides. Changing the solid / water ratio from 1:10 to 1:5 leads to an increase in the yield of lignin and easily hydrolyzed polysaccharides to 58 and 33.38 %, respectively.


Author(s):  
V. Nelyubova ◽  
V. Babaev ◽  
Nataliya Alfimova ◽  
S. Usikov ◽  
O. Masanin

fiber concrete is one of the types of effective building materials that ensure the operational reliability of structures due to a set of unique properties. However, the maximum physicomechanical characteristics of this type of products are achieved only if the fiber is evenly distributed in the concrete matrix and the optimum ratio of raw materials is reached. In this connection, the aim of the work was to increase the production efficiency of fiber-reinforced concrete by optimizing the formulation and technological parameters of its manufacture. The optimal method of introducing the fiber into the concrete mix and the type of superplasticizer were previously determined, which allowed ensuring the maximum physicomechanical characteristics of the products. Optimization of prescription parameters was carried out using the method of mathematical planning of the experiment, where the amount of cement, superplasticizer and basalt fiber were varied. After processing the results, the dependences of the compressive strength on variable factors were obtained, which would allow to select the optimal dosages of raw materials for given mechanical characteristics of the products.


2019 ◽  
Vol 828 ◽  
pp. 115-120 ◽  
Author(s):  
Narine Pirumyan ◽  
Mihran Stakyan ◽  
Gagik Galstyan

A mathematical model has been proposed for processing data from tests of building materials and obtaining optimal links between the characteristics of the bearing capacity and technological parameters of building materials for the use of these connections in refined design and construction procedures for building structures. To improve the accuracy of the results obtained, a three-level optimization principle was applied using the least squares method and a computational algorithm was compiled that allows us to develop an additional computational subroutine expanding the capabilities of the corresponding standard computer programs.


2019 ◽  
Vol 974 ◽  
pp. 255-260
Author(s):  
Ludmila A. Suleymanova

Theoretical and experimental materials for analyzing the technical capabilities of concrete are generalized and the physicochemical basis for the strength and durability of concrete is developed on the basis of the recent advances in building materials science and other sciences. That may increase the traditional concrete potential use and most importantly – to create the most firm and durable concrete of the new generation.


2019 ◽  
Vol 974 ◽  
pp. 195-200
Author(s):  
Yury R. Krivoborodov ◽  
Svetlana V. Samchenko

The article presents the results of a study of the effect of synthesized microdisperse additives of crystalline hydrates based on calcium sulfoaluminates on the properties of cement stone. The effectiveness of the use of a rotary pulsation apparatus (RPA) to obtain microdispersed additives is identified. The possibility of accelerating the hardening of cement stone by entering microdispersed additives into its composition is shown. It has been established that in the presence of microdispersed additives of crystalline hydrates in the cement stone, the phase composition of hydrate tumors changes, the amount of calcium hydrosilicates and ettringite increases, the porosity decreases and the strength of the cement stone increases. This provision is confirmed by the increase in the degree of cement hydration, the amount of bound water in all periods of hardening of the stone. It is proposed to use microdisperse additives, which play the role of primers for the crystallization of ettringite and calcium hydrosilicates, to increase the strength of cement stone in the early stages of hardening.


2015 ◽  
Vol 5 (4) ◽  
pp. 94-99 ◽  
Author(s):  
Anna Yur'evna ZHIGULINA ◽  
Natalya Genrikhovna CHUMACHENKO

The article is devoted to problems of creation of comfortable microclimate. Identifi es sources of pollution, completed their evaluation. Special att ention is paid to the selection of environmentally friendly building materials. In the production of building materials where toxic components can be industrial waste, replacing natural raw materials and chemical additives regulating the properties. In the operation of many building materials, especially those based on polymers, it is necessary to control the release of toxic substances resulting from degradation. For the assessment of comfort and environmental safety of housing is offered to create «Passports of residential buildings», which should be provided with information about construction materials used to evaluate this parameter, environmental home safety, including chemical safety as its component.


Author(s):  
S. Khanin ◽  
N. Kikin ◽  
O. Mordovskaya

Paddle mixers with horizontal shafts are common at building materials enterprises for the preparation of concretes, mortars, dry mortars. A new design of a horizontal paddle mixer with rod elements located in front of the working surfaces of the blades, changing the trajectories of material particles, increasing their mobility, which leads to an increase in the degree of homogeneity of the mixed material, is considered. The aim of the study was to assess the influence of rod elements on the quality of preparation of a cement-sand mixture, to establish patterns of influence on it by the design and technological parameters of a two-shaft paddle mixer and to determine the areas of their rational values. The following tasks have been solved. A bench installation of a two-shaft horizontal paddle mixer with rod elements has been developed, on which experimental studies have been carried out on the preparation of dry cement-sand mixtures. For the criterion characterizing the quality of the mixture, the ultimate compressive strength of the prism specimens made from it is adopted. Regression equations are obtained that adequately describe the compressive strength of prism samples from the design and technological parameters of the mixer: the angle of the blades, the distance from the working surfaces of the blades to the rod elements, the rotational speed of the blade shafts, and their analysis is performed. The analysis of the change in the ultimate compressive strength of the prism specimens from the parameters under study is carried out, the rational ranges of their values are determined. It was found that a mixer with rod elements allows to obtain a dry cement-sand mixture, products from which have a higher compressive strength. During the work, the method of mathematical planning of experiments was used. As a result of the study, an assessment of the influence of rod elements on the quality of preparation of a cement-sand mixture was carried out, the regularities of the influence on it of the design and technological parameters of a two-shaft paddle mixer and the area of their rational values were established.


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