Umarov Fahriddin

Rice. 1. Effect of different KH values and heat treatment temperatures 
on the kinetics of assimilation of CaO
svob.
 in two-component 
portland cement mixtures 

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Jundishapur Journal of Microbiology Research Article 
Published online 2022 April Vol. 15, No.1 (2022) 
5377 
0 
10 
20 
30 
40 
50 
800 
1000 
1200 
1400 
1600 
Т, °С, Burn..  
СаО, % 
Fig.2. Effect of different values of KH, n and heat treatment temperature on the kinetics 
of CaO
svob
 assimilation.
 
in ternary portland cement mixtures up to 1400 and 1450 
о
С assimilation of CaO
svob.
occurs 
more intensively and at temperatures of 1400 °C and above, the assimilation of CaO
svob. 
occurs almost completely. At the same time, it should be noted that in the composition with 
the content of KH = 0.89, already by 1400°C, the content of unbound free CaO is within the 
permissible range for ordinary Portland cements. 
In the graph of changes in the content of CaO
svob
in two-component mixtures (Fig.1.) 
in compositions with a low value of KH = 0.84 and 0.85, already at 1300 ° C, intensive 
assimilation of CaOsvob is observed, its content is 2.25-1.5%, and at a temperature 1400-
1450
о
С there is also intensive assimilation of CaO
svob
. 
In three-component raw mixtures with КН= 0.85 - 0.89 and n = 2.5 - 2.7 during heat 
treatment in different temperature ranges, intensive assimilation of CaO
svob
is also observed. 
(Fig.2.). Curves of changes in CaO
svob
content. in Portland cement raw mixes in the 
temperature range from 900°C to 1400°C shows that the process of CaO assimilation occurs 
already at a temperature of 1200°C, and at higher temperatures of 1350-1400°C in the studied 
mixtures, the content of CaO
svob
. is in the range of 1.0-0.3%, which indicates the completion 
of the process of mineral formation. At the same time, an increase in the silicate modulus, as 
expected, contributes to the assimilation of CaO, and an increase in the saturation coefficient 
from 0.85 to 0.89 leads to the formation of an excessive amount of CaO, which, with an 
increase in the heat treatment temperature to 1400°C, is also practically assimilated. 
The amount and type of hydrated compounds, such as hydrosilicates of different 
basicity, hydroaluminates and hydroferrites, formed during the hydration and hardening of 
cement stone, are well detected by X-ray phase analysis. 

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Jundishapur Journal of Microbiology Research Article 
Published online 2022 April Vol. 15, No.1 (2022) 
5378 
(5) 
(4) 
(3) 

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Jundishapur Journal of Microbiology Research Article 
Published online 2022 April Vol. 15, No.1 (2022) 
5379 
(2) 
(1) 
Rice. Fig. 3. Radiographs of Portland cement hydrated at different times of hardening: 
КН=0.89, η=2.7. 1- 1 day; 2-3 days; 3 -28 days; 4 -3 month; 5 - 6 months 
Rice. Fig. 3. Radiographs of Portland cement hydrated at different times of hardening: 
КН=0.89, η=2.7. 1- 1 day; 2-3 days; 3 -28 days; 4 -3 month; 5 - 6 months 
X-ray phase analysis of cement stone with different saturation coefficient and silicate 
modulus, hardened under normal conditions, shows that the hydration process and the 
formation of hydrated phases occur depending on the hardening time (Fig. 3). 
On the X-ray patterns of the samples hardened for 1 and 3 days, lines d = 0.491 are 
observed; 0.262; 0.193 nm, corresponding to Ca(OH)
2
, the intensity of which increases with 
time, which indicates the active hydration of the clinker. Also, lines d = 0.303 are observed 
on the radiographs; 0.280; 0.183 nm, corresponding to the main product of hydration of the 
silicate components of the clinker, tobermorite-like hydrocalcium silicate of the CSH type 
(B), which are covered by lines of the non-hydrated part of the tricalcium and dicalcium 
silicate. The lines corresponding to Ca(OH)
2
, which are insignificant at the initial stages of 
hardening, increase with increasing hardening time, which indicates that the hydration 
process continues intensively throughout the entire period of hardening of the samples. 
Thus, by studying the physicochemical characteristics of the process of hydration of 
experimental compositions of cement clinkers using Devanasay shale, Jizzakh limestone and 
slag waste from the Uzbek Metallurgical Plant, it was shown that, in terms of the content of 
the main components, the obtained two and three-component experimental Portland cements 
with different saturation coefficients and silicate module meet the requirements applied to 
industrial cements. 
The study of the physicochemical processes of hydration and hardening of cement 
stone using Devanasay shale from optimal compositions showed that hydration of clinker 
minerals occurs by rapid interaction of clinker minerals with mixing water, accompanied by 
the release of Ca(OH)
2
, insignificant in the early stages, increasing with increasing hardening 
time , which indicates that the hydration process continues throughout the entire period of 
specimen hardening with the formation of hydrosilicates, hydroaluminates, and calcium 
hydroferrites.