scholarly journals Rheological characteristics of the binder for foam concrete with a complex of mineral modifiers

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 180-184
Author(s):  
D. D. Netsvet ◽  
◽  
V. V. Nelubova ◽  

The paper considers the effect of mineral additives on the rheological characteristics of a binder for foam concrete. The compositions in the study were divided into two groups: based on nanostructured binder (NB) and based on cement. For the compositions of the first group portland cement is proposed as a modifying additive,for the compositions of the second group NB and anhydrite were used as modifying additives. It has been shown that the introduction of cement into NB increases the viscosity due to an increase in the concentration of large-sized particles, while the combined use of nanostructured binder and anhydrite as modifiers of the cement system helps to reduce the viscosity of the cement mortar and increase its mobility, which reduces the amount of mixing water. From a technological point of view, this will make it possible to obtain materials with a rational pore structure by optimizing porosity processes.

Author(s):  
Д. Нецвет ◽  
Dar'ya Necvet ◽  
В. Нелюбова ◽  
Viktoriya Nelyubova ◽  
В. Строкова ◽  
...  

The possibility of increasing efficiency of non-autoclaved foam concrete due to the use of complex binder with mineral components of different composition has been theoretically substantiated and experimentally confirmed. The opportunity to use the anhydrous calcium sulphate as a modifying component of the mixture is proved, which accelerates the setting of the mixture. This allows to "fix" the structure of the aerated concrete mixture with minimal shrinkage deformations. It is shown that the combined use of anhydrite and a mineral additive in the form of a quartz suspension obtained by grinding sand in an aqueous medium leads to a liquefaction of the mixture, which is associated with a decrease in the share of the structure-forming component. From a technological point of view, this will allow obtaining materials with a rational pore structure by optimizing the processes of pores formation. Composite binder with mineral additives is characterized by increased strength with a reduced share of clinker component in comparison with cement. In result, the minimization of shrinkable deformations and improvement of the quality of cellular concrete are ensured


2020 ◽  
Vol 17 (1) ◽  
pp. 122-135
Author(s):  
V. V. Voronov ◽  
E. S. Glagolev

Introduction. The paper devotes to the features of hydration and hardening of polymineral composite binders. The authors carry out the complex research of the phase composition, hydration and structure formation processes of hardened composite binders with active mineral additives by X-ray phase analysis, differential scanning calorimetry and electron microscopy. The study using a Tescan MIRA 3 scanning electron microscope reveals differences in the microstructure of hardened binders and the authors confirm the results by microprobe studies. The authors study the hydration of the composite binder prepared on the basis of Portland cement and mineral components. Moreover, the paper demonstrates the dynamics of the system’s heat dissipation from the moment of mixing with water and hardening up to 24 hours and up to 72 hours by the expressed bond of dQ / dt = f (t) using a differential calorimeter.Methods and materials. The authors carried out experimental studies at Belgorod State Technological University named after V.G. Shukhov, at the Department of Building Materials, Products and Structures, at the High Technology Center and “BelGTASM-Certificate” Test Center. Therefore, the authors used the existing basic research methods, including modern physicochemical methods of analysis: X-ray phase, scanning electron microscopy, etc. The paper determined the main characteristics of raw materials, composite binders and foam concrete using standard methods and regulatory requirements.Results. The authors obtained the results that testified the peculiarities of hydration and hardening processes of polymineral composite binders on the basis of Portland cement and mineral additives: opoka marl and fly ash.Conclusion. The research establishes the hydration and hardening processes of polymineral composite binders. As a result, the authors demonstrate that the opoka marl introduced into the cement leads to the increased hydration in the induction and accelerated periods and also increases the hydration completeness of the main clinker minerals due to the manifestation of the pozzolanic reaction and the active binding of blocking Portlandite, as well as to the higher concentration of accumulated neoplasms, second generation calcium hydrosilicates.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.


2020 ◽  
Vol 51 (1) ◽  
pp. 42-48
Author(s):  
Nikolay Karpenko ◽  
Vladimir Erofeev ◽  
Denis Emelyanov ◽  
Valery Fomichev ◽  
Alexey Bulgakov ◽  
...  

The paper presents the results of studies of the physical and mechanical properties of foam concrete on activated mixing water. Corrosion resistance of reinforcing steel in foam concrete with the use of activated water in the presence of mineral additives was studied. The use of activated with the electromagnetic field and electric current water of mixing enhances strength characteristics and reduce shrinkage deformation of composites. The increase of water resistance of foam concretes prepared on activated water of mixing compared with control compositions it was established. The comparative characteristic of foam concrete on the two types of foaming agent is given. The results of the anodic behavior of steel in activated water, characterizing the degree of aggressive influence on the steel depending on the activation mode and the chemical composition of mineral additives. This paper is a revised version of the paper (study) published earlier in the proceedings of the Creative Construction Conference 2018 (Karpenko et al., 2018).


Author(s):  
M. Elistratkin ◽  
S. Minakov ◽  
S. Shatalova

replacing portland cement with composite binders in many construction spheres is becoming increasingly reasonable. A prerequisite for this is the ability to provide the binder with set of properties necessary for the most effective implementation of a particular practical task at minimum expense. Such optimization allows in some cases to achieve higher performance than the original cement, in others – to form new properties of the material, as well as provide direct or indirect savings of various resources. One of the most important parameters determining the strength characteristics of composites and their durability is the used binder water requirement. Furthermore in some cases the mixture must have certain rheological characteristics. Various types and generations plasticizing and water reducing additives are widely used to regulate these parameters. The article discusses relation of fine components electrosurface properties – the clinker component and various genetic types mineral additives for the main types of plasticizers magnitude diluting effect. The basic mechanisms and regularities are described, recommendations that allow to optimize the consumption of expensive additives or increasing their effectiveness in solving various practical problems are formulated.


2021 ◽  
pp. 100182
Author(s):  
Alberto Muciño ◽  
Lauro Bucio ◽  
Eligio Orozco ◽  
Sofía Vargas ◽  
Nora A. Pérez

2021 ◽  
Vol 1090 (1) ◽  
pp. 012035
Author(s):  
Duaa Al-Faluji ◽  
Muna M. Al-Rubaye ◽  
Mohammed Salah Nasr ◽  
Ali A. Shubbar ◽  
Zainab S. Al-Khafaji ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1823
Author(s):  
Won-Kyung Kim ◽  
Young-Ho Kim ◽  
Gigwon Hong ◽  
Jong-Min Kim ◽  
Jung-Geun Han ◽  
...  

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction.


Author(s):  
Evangeline Lalrinmawii ◽  
Santosini Sahu ◽  
Pradip Sarkar ◽  
Robin Davis
Keyword(s):  

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