Umarov Fahriddin

Table 4 
Name of 
samples
Lineups 
Tensile strength, in MPa 
Hydrothermal treatment at 
95±5°C 
Normal storage 
3 nights 
28 days 
КН 
n 
bend 
compression 
bend compre
ssion 
bend 
compre
ssion 
СGl-4 
0,88 
2,
5 
4,7 
31,8 
4,8 
30,4 
6,5 
42,2 
СGl -5 
0,88 
2,
7 
4,5 
31,5 
4,6 
29,3 
6,2 
41,0 
СGl -6 
0,89 
2,
5 
4,6 
31,0 
4,7 
29,8 
6,5 
41,8 
СGl -7 
0,89 
2,
7 
4,5 
31,9 
4,9 
30,0 
6,6 
42,0 
The processes of hydration and hardening of cement stone is one of the main factors 
characterizing its performance properties. Numerous works of domestic and foreign 
researchers are devoted to the study of the processes of cement stone hydration [3-7]. 
In the process of hydration of cement stone, anhydrous clinker minerals calcium silicates, 
aluminates and aluminoferrites, interacting with mixing water, turn into hydrosilicates, 

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Jundishapur Journal of Microbiology Research Article 
Published online 2022 April Vol. 15, No.1 (2022) 
5376 
hydroaluminates and calcium hydroferrites. The speed and degree of hydration processes 
depends on the fineness of cement grinding, the temperature of the hardening medium, the 
water-cement ratio, as well as on the mineralogical composition of clinker, the material 
composition of cement, etc. [3,4] 
Therefore, it was of interest to study how the hydration process occurs in the developed 
cements based on Devanasay shale under normal hardening conditions. 
For research, cements based on clinkers with KH=0.85-0.89 and n=2.5-2.7 with the 
addition of natural gypsum were prepared, grinding to a residue of 8% on a №008 sieve. The 
hydration process was studied in cement mortars with a composition of 1:0, water-cement 
ratio W/C = 0.4 after 1 and 3 hours, as well as after 1, 3 and 28, 90.180 days after mixing 
with water. Before analysis, the hydration process was stopped by placing the test sample in 
anhydrous ethyl alcohol for 3 hours, then dried in an oven for 3 hours at a temperature of 40-
50°C. 
It is known that at the end of the clinker formation process, at KH ≤ 1.0, free calcium 
oxide (CaO
svob
) should be absent. However, under practical conditions, due to incomplete 
mineral formation or insufficient temperature or holding time at a given temperature, a small 
residual amount of CaO
svob
is determined in the clinker. According to the technological 
regulations of cement plants, the presence of CaO
svob
. in clinker is limited to 1.0-1.5%. 
Therefore, the change in the amount of CaO
svob. 
in Portland cement raw mixes is an important 
criterion for judging the kinetics and completeness of the formation of clinker minerals. 
In this regard, to determine the effect of KH and n on the kinetics of mineral 
formation in calcined Portland cement raw mixtures, the ethyl glycerate method of chemical 
analysis was used [1, 2]. For this purpose, two and three-component Portland-cement raw 
mixes with different КН = 0.84 ÷ 0.91 and n = 2.7 ÷ 3.2 were prepared. 
Figures 1 and 2 show the effect of different values of KH and heat treatment 
temperature on the kinetics of assimilation of free calcium oxide (CaO
svob
.) in two-
component and three-component Portland cement mixtures, respectively.