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5. Tajriba natijalariga ko‘ra klinker, gips va 15% barxan qumini qo’shib birgalikda
maydalab olingan sementning egilishga va siqilishga bo’lgan mustahkaligi 7,14 va 28 sutkadagi
aniqlanganida. Egilishga bo’lga mustahkamligi mikro to’ldirg’ichni sement massasiga nisbat
15% qo’shilganda 7 kunlik 2.77 MPa va 28 kunlik 5.9 MPa siqilishdagi mustahkamligi 7 kunlik
30.67 MPa va 14 kunlik 40.5 Mpa, 28 kunlik 53.9 MPa ga natijaga erishdi. Bu esa o‘z navbatida
loyihadagi nazorat namunasidan siqilishdagi mustahkamligi aniqlandi .
6. Umumiy xulosa qilib shuni takidlash lozimki mikro to’ldirg’ich asosan qorishmasining
plastikligini oshirish, suv miqdorini kamaytirish uchun foydalanishi, Barxan qumini 15%
sement massasiga nisbatan bir vaqtni o‘zida plastiklikni oshirish, mustahkamlikni oshirish,
qotish muddatlarini sekinlashtirish va sementni 15 % ga iqdisod qilish maqsadlarida
foydalanishga tavsiya etiladi.
FOYDALANILGAN ADABIYOTLAR RO’YXATI:
1. Otaqo’ziyev T.A., Otaqo’ziyev E.T. Mineral bog’lovchi moddalar kimyo
texnologiyasi. “Cho’lpon” nashriyot. Toshkent. 2005.
2. Qodirova D.Sh. Dissertatsiya “Бетоны на барханних песках и отсевах дробленя
порфиритов”. Toshkent-1987.
3. Mahalliy va ikkilamchi xom ashyolar asosidagi yangi kompozision materiallar.
Xalqaro ilmiy-texnik konferensiya materiallari. Toshkent. ToshDTU. “Fan va taraqqiyot”
DUK. 2011y.
4. Weimarer Ginstagung. F.A. Finger – Institut fur Baustoffkunde. Bauhaus –
universitet Weimar. Bundes – republic Deutsland. 30.-31. Marz. 2011.
5. Gaziev U.A., Kadirova D.Sh. Beton va qorishmalar uchun qo‘shimchalar. O‘quv
qo‘llanma. 2015.
ADDITIVES TO INCREASE FIRE RESISTANCE OF BUILDING
CONSRUCTIONS FOR OIL AND GAZ INDUSTRY
Akhmedov
1
S.I., Mukhidova
2
Z.SH., Mukhamedov
1
N.A.
1-
Tashkent Institute of Architecture and Civil engineering
2-
Branch of Astrakhan State Technical University in Tashkent region
Today, with the development of the construction industry, the demand for cement is also
increasing. In increasing the volume of construction, cement is one of the resources available
at the price of finished objects is achieved through cost reduction due to the use in the
construction of modern high-quality building materials and products with lower energy
consumption and with improved characteristics. Of particular importance is the production of
effective cements based on industrial waste. On a global scale, special attention is paid to the
development of new compositions of cements that increase the fire resistance of building
structures and the most important task of research in this direction is the development of
compositions based on industrial waste for Portland cement. When developing composite
additives and based on them new compositions of highly effective composite Portland cement,
in this direction it is necessary to substantiate a number of the following scientific solutions, in
particular: development of new methods for the production of effective types of building
products based on composite additives; development of new compositions for the production
of nanocements with the participation of secondary raw materials; increase of concrete strength
indicators on sulfate-resistant cements; optimization of the composition of raw materials in
obtaining energy-saving clinkers and cements; modernization of production technologies for
white and decorative Portland cement; to increase the production of auxiliary cements, the use
of alternative sources of active mineral additives and filler additives.
In the Republic of Uzbekistan, large-scale measures for the production of high-quality
cements are carried out, aimed at meeting the demand for cement, modernization of the
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economy and the creation of new production capacities are achieved. The Strategy for the
Development of the Economy of the Country defines the tasks “development of production
sectors, modernization and diversification of industry, in practice, apply methods of low-
energy-saving technologies, production, modernization and diversification of industry, in
practice, apply methods of low-energy energy-saving technologies, the development of the
cement industry, the manufacture of import-substituting and export-oriented products." In this
matter, scientific research aimed at the development of new compositions of composite
additives based on industrial waste and new compositions of effective cements with their use is
of great importance. Fire resistance is the ability of building structures to limit the spread of
fire, as well as maintain the necessary performance at high temperatures in a fire [1].
Heat-resistant concrete is a special type of material that, under the influence of high
temperatures (up to 1800 ° C), is able to maintain its own physical and mechanical
characteristics within established limits. Heat-resistant mixtures are successfully used in all
areas of industrial construction, in no way inferior to small-sized refractory materials. For
example, heat-resistant concrete GOST 20910–90, in comparison with conventional refractory
materials, do not need special preliminary firing. Heat treatment (firing), heat-resistant
concrete, takes place during limits. Heat-resistant mixtures are successfully used in all areas of
industrial construction, in no way inferior to small-sized refractory materials. For example,
heat-resistant concrete GOST 20910–90, in comparison with conventional refractory materials,
do not need special preliminary firing. Heat treatment (firing), heat-resistant concrete, takes
place during the first heating of the finished structure, at the time of the start-up of the thermal
unit [2].
Data on the limits of fire resistance and fire spread are used in the design of buildings
and structures. The latter, according to regulatory documents, are divided by degree of fire
resistance into five groups. For them, the required limits of fire resistance (minimum) and the
spread of fire (maximum) of the main building structures are established. Depending on their
type, the indicated limits of fire resistance vary from 0.25 to 2.5 hours, the limits of the spread
of fire from 0 to 40 cm.The increase in fire resistance is achieved by fire protection methods.
To improve the structure of the cement composition and increase the strength of
structures, mineral components (battle of magnesite or fireclay bricks, andesite, blast-furnace
granulated slag, loess like loam, fly ash, etc.) are added to the binder, which have the necessary
fire resistance. When heating reinforced concrete structures, destructive processes occur not
only in cement binders, but also in the used aggregates. The occurrence of these reactions is
explained by the uneven thermal expansion of the mineral aggregates. Therefore, you need to
carefully approach the issue of choice of aggregates for a particular brand of heat-resistant
concrete. We conducted studies to determine the possibility of the integrated use of
mechanically chemically activated additives of the МНА series based on the ash and slag of the
Novo-Angren TPP (thermal power plant) and the phosphogypsum waste of «Maxam-
Ammofos» OJSC.
The SO
3
content is 21.89% and 13.36% in МНА-1 and МНА-2, respectively, the results
of chemical analysis of the mechanically chemically activated additives of the МНА series
indicate the possibility of their use as active mineral additives, and possibly a setting time
regulator in return gypsum stone for fire-resistant and heat-resistant cements, concrete and
building structures. According to table 2, in the initial stages of hardening, the strength of
cements PМНА-2-15, PМНА-2-20, at the age of 7 days amounted to 26.8 MPa and 24.1 MPa,
respectively, which practically does not differ from the strength of the control cement PC-A0
(26.8 Mpa). The chemical activity of the mechanically chemically activated additive "МНА"
in the absorption of lime was 54.5 mg, which corresponds to the minimum permissible activity
characteristic of the group of artificial (technogenic) aluminosilicate hydraulic additives.
Therefore, the МНА additive is a chemically active mineral additive, and is classified by its
origin (manufacture) as an artificial additive of technogenic origin, acidic in chemical
composition,and hydraulic in chemical activity. Despite the presence of many modern and
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interesting construction solutions with the “МНА-1” on the based, traditional monolithic flat
still has numerous followers. This is caused by a few different reasons. First and foremost,
when building home flat and flooring, there is no need to use heavy equipment. Besides,
construction materials necessary for building it can be acquired without problems – steel bars
and concrete can be bought easily, while planks can be later used to build the roof.
Furthermore, monolithic flat can be built in a variety shapes, also including atypical, with the
“МНА-1”. That and it is not too thick (from a few to a dozen or so centimeters) and is
characterized by good acoustic and thermal insulation characteristics. If it is building
according to the best construction practices, reinforced concrete flooring forms a smooth and
even surface on both sides that is the floor and the ceiling. Unfortunately, they also have
some disadvantages. Primarily, they are relatively heavy and building them is labor-intensive
with the “МНА-1”, since they require full formwork and complicated reinforcement,
constructed by a professional. Furthermore, there should be no stoppages during the works –
after setting up the formwork and reinforcement with the “МНА-1”, concrete should be poured
immediately, of course while remembering to vibrate and cure it properly. Unassisted
construction with the “МНА-1” of such flooring is impossible and thus help of excellent
professionals should be employed during the mentioned works.
The results of electron microscopic analysis of the МНА additive confirm the formation
of a crystalline structure during the autoclave treatment of a mixture of phosphogypsum and
ash and slag, and that it is similar to the structure of hardening cement paste in the early periods
of hardening and is represented mainly from hydrated sulfate-containing minerals and
neoplasms in the form of hydrosulfoaluminate and low basic hydro silicate compounds.
When “МНА” additives are introduced into the cement, these hydrated neoplasms play
the role of crystalline seeds — “crystallization centers”, which initiate the emergence of new
nuclei of the hydrosulfoaluminate and hydrosilicate type neoplasms, accelerate their
crystallization and the formation of the crystalline skeleton of the hardening cement dispersion,
and as a result intensify the processes of hydrolysis and hydration of aluminate and silicate
minerals of clinker PC.
To study the effect of the additive “МНА-1” on the physic-mechanical properties of the
PCs of JSC “Bekabadcement”, blends were prepared including “65-85% PC clinker + 15-35%
“МНА-1”, and for comparative tests -“ 95% PC clinker + 5% gypsum stone. The additive
"МНА-1" was introduced into the raw material charge taking into account the content of 8.56%
SO3. It has been established that in the presence of “МНА-1” additive, the grindability of
mixtures is increased compared to grinding clinker PC with 5% gypsum stone: with a constantly
fixed time (40 min), the fineness of grinding cements with “МНА-1” determined by the residue
on sieve No. 008, varies within (2-6)% compared with 10% of the remainder of PC-D0.
Cements with the addition of “МНА-1” meet the requirements of GOST 10178 on the content
of SO3 (2.33-3.80%), because for ND, the optimal SO
3
content in the PC should be at least
1.0% and not more than 4.0% by weight. The rates of initial reactions of cements with the
addition of “МНА-1” with water are little different from the rates of reactions of a non-additive
PC. The process of starting the setting of cements PC-F15, PC-F20, PC-F 25 is extended by
(15-30) min.
The increase in water demand of additional PCs is explained by the increased content
of aluminate phases in them and a finer degree of grinding in comparison with PC-D0 cement.
In accordance with the data in table 4, the strength of cement with the addition of 15% “SIA-
1” (PC-F15), both at the age of 28 days of normal hardening, and with longer curing (3 months)
practically do not differ from the strength of cement PC-D0. Constructions with a new fire
additive all over the world rely on concrete as a strong material that provides fire safety and is
easy to handle. It can be found in almost all building types – residential, oil and gas reservoirs
storage, multi-flat and even in municipal infrastructure. Despite its wide range of use, many
of its users still do not know about the fire materials with the “МНА-1” directly connected to
ensuring the endurance and high quality of concrete. The term “concrete strength class” means
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the endurance of concrete against compression, no more, no less. It determines the amount of
stress the material can take. Concrete strength is determined by measuring the crushing
strength of cubes or a cylindrical sample made from a pre-prepared mixture. After the
measuring and strength determining, concrete is assigned a strength class.
Based on the studies, a technology has been developed to produce effective composite
additives from industrial waste - a mechanically-chemically activated mixture of ash from the
Novo-Angren TPP + phosphogypsum. Taking into account the double effect on the cement of
the mechanically chemically activated mixture “МНА-1” in the amount of 15-20% as an active
mineral additive and a regulator of setting time instead of natural gypsum stone, its large-scale
introduction is recommended.
REFERENCE.
1. Khasanova O.T. Some problems of increasing the fire resistance and heat resistance
of concrete.
Readings of A.I. Bulatov: Materials of III-International scientific and practical
conference (on March 31, 2019) in 5 vol.4: Chemical technology and ecology in the oil and gas
industry. Conference bulletin Krasnodar (Russia), 2019.
2. Basin B.U. Fire resistance and heat resistance betons. Moscow, 2014.-c.340.
“SIKA RETARDER” SUPERPLASTIFIKATORINI PORTLANDSEMENT
XOSSALARIGA TA’SIRINI O’RGANISH
Assistent Xoltayeva A.K.
Toshkent arxitektura-qurilish universiteti
Annotatsiya. Maqolada Sika Retarder superplastifikatorining portlandsementning fizik
va mexanik xossalariga ta’siri laboratoriya sharoitida o’rganilgan hamda olingan natijalar
jadval va grafik ko’rinishlarida berilgan.
Аннотация. В данной статье были исследованы физические и механические
свойства бетона с суперпластификаторoв Sika Retarder, а также приведены
результаты лабораторных исследований в виде таблицы и графиков.
Аbstract. In this article was studied the physical and mechanical properties of concrete
with superplasticizers of Sika Retarder, as well as the results of laboratory studies were given
in the form of the table and graphs.
Kalit so’zlar: sement, portlandsement, Sika Retarder, plastifikator, superplastifikator,
sirt faol modda, kimyoviy qo’shimcha, mustahkamlik, suv-sement nisbati.
Bugungi kunga kelib beton va temir-beton zamonaviy qurilishda asosiy material bo’lib,
ularning xususiyatlarini yaxshilash maqsadida turli xil qo’shimchalar qo’llanilmoqda. Hozirgi
kunga kelib kimyoviy qo’shimchalar beton qorishmasining bog’lovchi, to’ldiruvchi, suv kabi
majburiy komponentlaridan biri bo’lib qoldi.
Qo’shimchalar yordamida betonning texnologik parametrlarini boshqarish, reologik va
ekspulatatsiya xossalarini yaxshilashning zamonaviy usullaridan biri deb hisoblanadi.
Qo’shimchalarni qo’llanilishi qurilishdagi sarflarni kamaytirish, masalan, qurilishni
narxini kamaytirishi, sement sarfini iqtisod qilish va betonni sifatli tayyorlash imkonini beradi.
Beton qorishmalarini xarakatchanligini oshishi suv talabchanligini saqlab qolgan holda mehnat
sarfi darajasini pasayishiga olib kelib, elektr energiyaning kam sarflanishiga va beton
qorishmasini zichlashtirish davomiyligini qisqartirish imkonini beradi [1].
