scholarly journals Kinetics of structure formation in the vicinity of the glass transition

2022 ◽  
pp. 117630
Author(s):  
Jürgen E.K. Schawe ◽  
Jörg F. Löffler
Author(s):  
V.I. Tarasevych ◽  
◽  
Yu.G. Gasan ◽  
V.B. Dolgoshey ◽  
◽  
...  

The paper considers the issues of studying the structure formation of binders during hardening to determine the optimal moments of mechanical action on gypsum concrete specimens, which makes it possible to optimize the technology of their impregnation with sulfur melt. The time dependence of the elastic modulus of a hardening, binder is its important physicochemical characteristic, since it is used to objectively identify the stages of structure formation, to simulate the processes occurring at each of the stages. It is noted that the method of acoustic resonance of bending vibrations, in the case of hardening binders, needs correction with respect to the measurement technique and interpretation of the results obtained. The kinetics of the resonance frequency of a sample consisting of a rigid cell and a dispersion poured into it is a function of the elastic properties of the cell, the dispersion itself, the contact zone of the dispersion with cell and therefore cannot be used for either qualitative or quantitative analysis of the kinetics of hardening. Taking into account the elasticity of cuvette is necessary to obtain reliable information. It has been established that in the presence of shrinkage or significant expansion of the binder, the study of structure formation by the resonance method should be carried out in plastic cuvettes. Regardless of shrinkage, the use of a cuvette requires compulsory consideration of its elastic properties. It is advisable to objectively distinguish the stages of structure formation on the basis of the kinetics of not the dynamic modulus of elasticity itself, but the rate of its change. The time dependence of the logarithmic damping decrement is also an important characteristic of the concrete structure. The studies carried out make it possible to obtain serogypsum composites with the necessary performance characteristics and to manufacture elements of architectural décor, wall fencing products of increased aesthetics, durability and reliability from them.


2018 ◽  
Vol 124 (2) ◽  
Author(s):  
Sherouk Sh. El-sonbaty ◽  
M. I. Abd-Elrahman ◽  
A. A. Abu-Sehly ◽  
M. M. Hafiz

Author(s):  
T Shanker Rao ◽  
T Lilly Shanker Rao ◽  
A M Shaker ◽  
K Venkataraman

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