scholarly journals THE EFFECT OF INORGANIC ELECTROLYTES ON THE ACCELERATION OF PORTLAND CEMENT SYSTEMS SETTING

Author(s):  
Shark M. Rakhimbaev ◽  
◽  
Tatiana V. Anikanova ◽  
Anastasia V. Prokopishina ◽  
Alexey S. Pogromskiy ◽  
...  

The study showed that in order to accelerate the hydration of inorganic binders it is necessary to use additives of such electrolytes that increase the concentration of calcium ions in the liquid phase of the cement suspension. Electrolytes (soda ash, sodium and potassium hydroxides), precipitating calcium ions in the liquid phase, promote their exit from the "shut-off" layer of hydration products. In this paper, we studied the additives – electrolytes – as regulators of the setting time of fine-grained and porous concrete. To increase the activity of the additive as a concrete mixtures setting time regulator, acidic varieties were used instead of main salts. The studied additives – electrolytes – draw practical interest, as their usage in production of foam concrete and fine-grained concrete lets accelerate hardening of products and speed up reuse of mould.

2021 ◽  
Vol 1895 (1) ◽  
pp. 012027
Author(s):  
Hussein J. Almansori ◽  
Adnan Al-Sibahy ◽  
Basim Al-Humeidawi

1958 ◽  
Vol 25 (2) ◽  
pp. 307-311 ◽  
Author(s):  
C. Sterling

A viscometric study of solutions of alkaline (sodium and potassium) caseinate was made to determine the effects of renneting with and without the addition of calcium ions. There was no real viscometric effect of these treatments at high dilutions. At a higher temperature, the viscosity increment of the solutions decreased. It was suggested that particle aggregation occurs more readily at higher temperatures, leading to a greater particle symmetry as well as causing some dehydration.


Author(s):  
Zhuliang Yao ◽  
Shijie Cao ◽  
Wencong Xiao ◽  
Chen Zhang ◽  
Lanshun Nie

In trained deep neural networks, unstructured pruning can reduce redundant weights to lower storage cost. However, it requires the customization of hardwares to speed up practical inference. Another trend accelerates sparse model inference on general-purpose hardwares by adopting coarse-grained sparsity to prune or regularize consecutive weights for efficient computation. But this method often sacrifices model accuracy. In this paper, we propose a novel fine-grained sparsity approach, Balanced Sparsity, to achieve high model accuracy with commercial hardwares efficiently. Our approach adapts to high parallelism property of GPU, showing incredible potential for sparsity in the widely deployment of deep learning services. Experiment results show that Balanced Sparsity achieves up to 3.1x practical speedup for model inference on GPU, while retains the same high model accuracy as finegrained sparsity.


2018 ◽  
Vol 931 ◽  
pp. 573-577
Author(s):  
Vladimir N. Morgun ◽  
Lyubov V. Morgun

The scientifically grounded and experimentally confirmed features of formation of stable foam concrete mixes in time are considered. It is shown that the formation of such gas-filled structures is possible only with water content, the value of which is sufficient for wetting the surface of all solid dispersed particles of raw materials, the formation of foam films and the processes of adsorption and chemical hydration of binder particles. It is proved that taking into account the value of the aeration potential of the foaming agent, it is possible to obtain stable foam concrete mixtures of a given density


Author(s):  
Nuan La Ong Srakaew ◽  
Sirirat Tubsungnoen Rattanachan

Self-setting calcium phosphate cement (CPC) has been used in bone repair and substitution due to their excellent biocompatibility, bioactive as well as simplicity of preparation and use. The inherent brittleness and slow degradation are the major disadvantages for the use of calcium phosphate cements. To improve the degradation for the traditional CPC, the apatite cement formula incorporated with β-tricalcium phosphate (β-TCP) with varying concentration were studied and the effect of the pH value of liquid phase on the properties of this new calcium phosphate cement formula was evaluated. The apatite cements containing β-TCP for 10 and 40 wt.% were mixed into the aqueous solution with different pH values and then aging in absolute humidity at 37°C for 7 days. The setting time and phase analysis of the biphasic calcium phosphate were determined as compared to the apatite cement. For proper medical application, the compressive strength, the phase analysis and the degradation of the CPC samples at pH 7.0 and 7.4 were evaluated after soaking in the simulated body fluid (SBF) at 37°C for 7 days. The results indicated that the properties of the samples such as the setting time, the compressive strength related to the phase analysis of the set cements. The high degradation of the CPC was found in the cement with increasing β-TCP addition due to the phase after setting. Apatite formation with oriented plate-like morphology was also found to be denser on the surface of the biphasic bone cements after soaking in SBF for 7 days. The obtained results indicated that the cement containing β-TCP mixed with the liquid phase at pH 7.4 could be considered as a highly biodegradable and bioactive bone cement, as compared to the traditional CPC.


2019 ◽  
Vol 802 ◽  
pp. 1-15
Author(s):  
Sergey Victorovich Daletsky ◽  
Yuri Mikhailovich Kolitievsky ◽  
Victor Vasilievich Nikonov ◽  
Nikolay Nikolaevich Sirotin ◽  
Vladimir Vladimirovich Yudaev

The article consists in the development of compositions of self-compacting powder-activated fine-grained (sand) concrete mixtures, including color ones, for the production of high-density, high-strength and durable architectural and decorative concretes, which do not lose their architectural appeal during long-term operation, on the basis of multi-tonnage waste of stone crushing of various rocks, without the use of expensive mineral reactive components and the study of their physical and technical properties.


2018 ◽  
Vol 276 ◽  
pp. 116-121 ◽  
Author(s):  
Alsu Khamatova ◽  
Grigory Ivanovich Yakovlev ◽  
Vadim Khozin ◽  
Grigory Nikolaevich Pervushin

The physicochemical and physicomechanical properties of quick-setting compositions based on fine-grained electric steelmaking slag (ESS) produced by Izhstal PJSC, Russia, have been examined. The study also focuses on the processes of interaction of the components of the compositions based on ESS in combination with hardening accelerators (Li2CO3, K2SO4) and plasticizing additives (SP-1, Melflux 2651F). It has been found that mechanoactivation of the composition improves the hydration in comparison with chemical admixtures. This can be proved by the obtained results of the setting and testing timing of the mechanical properties of the mixture. Plasticizers being added, the setting time increases at the average by 2.3 times, and accelerators being added, by 2 times compared with the mechanically activated composition. The influence of mechanoactivation on the strength of the compositions has been described. In comparison with the plasticized composition, the strength increases by 10%, while using accelerators – by 30%. Thus, the most effective way of producing a dry mixture with the properties of quick setting and hardening is a short-term mixed grinding of all its components, which makes it possible to exclude accelerating chemical admixtures and plasticizing additives in the mixture. Also, grinding positively affects the strength gain of quick-setting compositions while reducing the gypsum content to 5%.


1989 ◽  
Vol 180 (2) ◽  
pp. 362-367 ◽  
Author(s):  
Hideaki Nagamune ◽  
Osamu Urayamaj ◽  
Yukichi Hara ◽  
Fusao Ota ◽  
Katsuhiko Hirota ◽  
...  

Author(s):  
JIANYONG CHEN ◽  
QIUZHEN LIN ◽  
QINGBIN HU

In this paper, a novel clonal algorithm applied in multiobjecitve optimization (NCMO) is presented, which is designed from the improvement of search operators, i.e. dynamic mutation probability, dynamic simulated binary crossover (D-SBX) operator and hybrid mutation operator combining with Gaussian and polynomial mutations (GP-HM) operator. The main notion of these approaches is to perform more coarse-grained search at initial stage in order to speed up the convergence toward the Pareto-optimal front. Once the solutions are getting close to the Pareto-optimal front, more fine-grained search is performed in order to reduce the gaps between the solutions and the Pareto-optimal front. Based on this purpose, a cooling schedule is adopted in these approaches, reducing the parameters gradually to a minimal threshold, the aim of which is to keep a desirable balance between fine-grained search and coarse-grained search. By this means, the exploratory capabilities of NCMO are enhanced. When compared with various state-of-the-art multiobjective optimization algorithms developed recently, simulation results show that NCMO has remarkable performance.


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