EVALUATION OF PHYSICO-CHEMICAL EFFICIENCY OF MINERAL ADDITIVES OF VARIOUS COMPOSITIONS IN CEMENT SYSTEMS

2021 ◽  
pp. 41-47
Author(s):  
Tatyana Anatolyevna Nizina ◽  
Artemiy Sergeevich Balykov ◽  
Dmitry Igorevich Korovkin ◽  
Vladimir Vladimirovich Volodin ◽  
Sergey V. Volodin
2021 ◽  
Vol 1926 (1) ◽  
pp. 012068
Author(s):  
T A Nizina ◽  
A S Balykov ◽  
D I Korovkin ◽  
V V Volodin

2021 ◽  
Vol 1 (12) ◽  
pp. 55-58
Author(s):  
Z. S. Khabadze ◽  
Yu. A. Generalova ◽  
Ya. A. Negorelova ◽  
F. R. Ismailov ◽  
E. S. Shilyaeva

The purpose of this systematic review of the literature is to detail the main physical, chemical, biological, operational, and other significant properties of bioceramic materials used in endodontic practice ю Фccording to the studied literature, we can say that bioceramic endodontic materials have satisfactory performance properties, are characterized by antimicrobial action and alkaline pH, have optimal biocompatibility and bioactivity, which indicates the feasibility of their use in the clinical practice of a dentist-endodontist.


2020 ◽  
Vol 2020 (2) ◽  
pp. 107-112
Author(s):  
Iryna Kirakevych ◽  
◽  
Myroslav Sanytsky ◽  
Igor Margal ◽  
◽  
...  

In the article the features of reinforced concrete hardening at different temperature conditions and the current issues of preparation technology of Self-Сompacting Сoncretes (SCC) on the basis of superplasticized cementitious systems, combining knowledge of structure and modifying Portland cement compositions "Portland cement – active mineral additives – microfiller – superplasticizer – accelerator of hardening" to search for rational making provision of technical and building properties of concrete in the changing factors of its composition, technology and exploitation are shown. The physico-chemical peculіarities of hydration and hardening processes of superplasticized cementitious systems were established. The problem of obtaining Self-Compacting mixtures and Rapid-Hardening Concretes on their basis by the direct structure formation of cementitious matrix was solves. The optimization of Self-Compacting Concretes composition on the base of superplasticized cementitious systems with high early strength was carried out. The quality parameters of developed concretes were investigated and the effectiveness of their using in different temperature conditions was shown. The results of the studies found that the use of the superplasticized cementitious systems allows to influence on technological properties and kinetics of structure formation and create concrete structure with improved construction and technical properties at a different temperature conditions. Technological solutions designing of superplasticized cementitious systems that solves the problem of obtaining the Self-Сompacting Сoncretes (SCC) on their basis with using non-vibration technology are established. This creates an opportunity allows to solve the problem of obtaining for enabling early loading, reducing the production cycle, increasing turnover and formwork acceleration of monolithic buildings and structures at different temperature conditions.


2018 ◽  
Vol 180 ◽  
pp. 199-210 ◽  
Author(s):  
Anja Terzić ◽  
Lato Pezo ◽  
Nevenka Mijatović ◽  
Jovica Stojanović ◽  
Milan Kragović ◽  
...  

2021 ◽  
Vol 1017 ◽  
pp. 61-70
Author(s):  
Artemy S. Balykov ◽  
Tatyana A. Nizina ◽  
Vladimir V. Volodin ◽  
Vladimir M. Kyashkin

Introduction of finely disperse mineral additives of natural and man-made origin to Portland cement in order to improve the indicators of its physical-mechanical properties and partially replace clinker is one of the urgent directions for solving the resource and energy saving problems, as well as environmental protection problems in the production and application of building materials. The expansion of the raw material base of mineral additives can be achieved by using calcined polymineral clays, which are common in many regions of the Russian Federation, including the Republic of Mordovia. The article presents the results of research on the effects of calcination temperature and time of thermally activated polymineral clays of the Republic of Mordovia on their physical-chemical efficiency in cement systems. According to the study results of dehydration processes of clay minerals using the synchronous thermal analysis, it is established that the optimum calcination temperature for clays of Nikitsky and Staroshaigovsky deposits located in the area of 500–800 °C. This temperature range corresponds to the processes of the initial crystal structure restructuring of clay minerals of the kaolinite and illite groups, associated with their dehydroxylation, which contributes to the transition of these phases to the active form. The optimization of calcination parameters of polymineral clays based on the study results of influence of their additives on the mixed cement binder activity confirmed the thermal analysis data. It was found that the production of mineral additives with the highest values of the activity index is facilitated by 2-hour heat treatment of clays at 700 °C. At the specified calcination parameters, the replacement of 10% of Portland cement with the additive of thermally activated Nikitsky clay allows achieving the mixed binder activity that exceeds by 3 % the same indicator of mixed binder based on Portland cement and high-quality metakaolin.


Desalination ◽  
2006 ◽  
Vol 200 (1-3) ◽  
pp. 189-191 ◽  
Author(s):  
David Delaunay ◽  
Murielle Rabiller-Baudry ◽  
Lydie Paugam ◽  
Arto Pihlajamäki ◽  
Marianne Nyström

2021 ◽  
Vol 2021 (1) ◽  
pp. 79-84
Author(s):  
Iryna Kirakevych ◽  
◽  
Myroslav Sanytsky ◽  
Orest Shyiko ◽  
Roman Kagarlitsky ◽  
...  

The paper presents the results of research concerning the peculiarities of modern High Performance Concretes based on cementitious systems "Portland cement – active mineral additives – micro fillers – superplasticizers – accelerators of hardening". Physico-chemical regularities of structure formation of super plasticized cementitious systems are established. It is shown that the formation of secondary fine ettringite due to the interaction of active alumina with calcium hydroxide and gypsum in the non-clinker part of the binder because of the effect of "self-reinforcement" compensates for shrinkage and increases the strength of the cementitious system. The modification of the cementitious matrix makes it possible to obtain Rapid Hardening High Performance Concretes that provide early loading and turnover of the formwork of monolithic constructions.


Homeopathy ◽  
2017 ◽  
Vol 106 (04) ◽  
pp. 240-249 ◽  
Author(s):  
Abhirup Basu ◽  
Akkihebbal Krishnamurthy Suresh ◽  
Shantaram Govind Kane ◽  
Jayesh Ramesh Bellare

Background: Potentization, consisting of serial dilution and succussion, is a key step in the manufacture of homeopathic medicines. Originally prescribed as a manual process, several attempts at mechanization have been published, patented and even commercialised in order to remove the human element and introduce reproducibility without drudgery. Various machines have been used over the years to prepare homeopathic medicines. Although these machines follow the same principles, i.e. energetically mixing the medicines and diluting them significantly, their mode of operation is different from each other. Methods: This review paper surveys the main methods of preparation of homeopathic medicines. The main machines discussed are: Boericke's potentizer, Tyler Kent's instrument, John Alphonse's machine and the fluxion potentizer, which were used in the past, as well as more recent potentizers like arm-and-weight instruments, the K-Tronic potentizer and Quinn's machine. We review the construction and operating principle of each of these machines, along with their advantages and limitations. A scheme for relative performance assessment of these machines is proposed based on the parameters mechanical efficiency, physico-chemical efficiency, turbulence generation, energy dissipation, and accuracy of dilution. Results: Quinn's machine and the arm-and-weight potentizer perform well for generating turbulence due to high impaction forces, while John Alphonse's machine is much more accurate in diluting the homeopathic medicines at every step. Conclusions: Both the commercial potentizers, Quinn's machine and the K-Tronic potentizer, are completely automated and therefore reduce the manual labour and variation in succussive forces during each step, which may produce uniformity in physico-chemical changes within the resulting homeopathic medicines.


Author(s):  
H. Gross ◽  
H. Moor

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.


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