INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 04,2025
Journal:
https://www.academicpublishers.org/journals/index.php/ijai
page 337
METHODS FOR INVESTIGATING THE PHYSICO-MECHANICAL PROPERTIES
OF HEAT-RESISTANT CONCRETE
Bahromjon Adxamovich Otaqulov
Fergana State Technical University
Abstract:
This article is devoted to the study of methods for investigating the physico-
mechanical properties of heat-resistant concrete. The research utilized literature analysis,
experimental testing methodology, physico-mechanical tests, and statistical analysis to
determine the behavior of concrete under high-temperature conditions. Samples prepared from
local raw materials (cement, gravel, sand) and heat-resistant additives (aluminum oxide,
shungite) were tested at temperatures of 200°C, 400°C, and 600°C. The results revealed that as
temperature increased, compressive strength decreased by up to 53%, while additives improved
stability by 10-15% (p < 0.05). The article analyzes the advantages and limitations of the
applied methods and evaluates the potential for utilizing local resources in Uzbekistan. The
findings contribute to the adoption of environmentally friendly and cost-effective materials in
the construction industry.
Keywords:
Heat-resistant concrete, physico-mechanical properties, research methods, local raw
materials, aluminum oxide, shungite, statistical analysis, ecological sustainability, construction
materials.
Introduction
Heat-resistant concrete (HRC) holds significant importance in modern
construction as a specialized material capable of retaining its physico-mechanical properties
under high-temperature conditions. This type of concrete is particularly utilized in industrial
structures (e.g., metallurgical furnaces, thermal equipment) and buildings with elevated fire
risks. In Uzbekistan, the rapid development of the construction industry, coupled with an
increasing demand for environmentally friendly and economically efficient materials, has made
the in-depth study of heat-resistant concrete a pressing task. The heat resistance of concrete is
directly tied to its strength, density, and stability, which vary depending on its composition,
production technology, and testing conditions. Consequently, the use of appropriate research
methods is of critical importance.
Uzbekistan has opportunities to utilize local raw materials (cement, sand, gravel) and industrial
waste (e.g., phosphogypsum), aligning with the country’s “Green Economy” strategy.
Employing local resources in the study of heat-resistant concrete is not only economically
advantageous but also contributes to addressing environmental challenges. However, the lack of
precise data on the behavior and changes in the physico-mechanical properties of concrete
under high-temperature conditions further underscores the relevance of this research.
The objective of this article is to comprehensively analyze the research methods used to
determine the physico-mechanical properties of heat-resistant concrete, assess their
effectiveness, and explore the potential for utilizing local raw materials in Uzbekistan. During
the research, the use of additives (aluminum oxide, shungite) to enhance heat resistance and the
efficacy of local resources were tested.
Methods
A comprehensive methodological approach was employed to investigate the physico-
mechanical properties of heat-resistant concrete. These methods are detailed below:
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 04,2025
Journal:
https://www.academicpublishers.org/journals/index.php/ijai
page 338
1.
Literature Analysis:
To establish the theoretical foundation of the research, local and
international scientific sources on the physico-mechanical properties and heat resistance
of concrete were reviewed. Specifically, Neville’s (2011) Properties of Concrete served
as a basis for analyzing general concrete properties, while Bazhenov (2015) provided
specialized insights into heat-resistant concrete technology. Scientific articles published
in Uzbekistan were also analyzed.
2.
Experimental Testing Methodology:
Concrete samples were prepared using M400-
grade cement produced in Uzbekistan, local gravel, sand, and heat-resistant additives
such as aluminum oxide (Al₂O₃) and shungite. The sample composition was as follows:
cement – 400 kg/m³, gravel – 1200 kg/m³, sand – 600 kg/m³, water – 180 l/m³, additives
– 5-10% (aluminum oxide – 5%, shungite – 5%). The samples were cast into 15x15x15
cm cubes and cured under standard conditions (20°C, 95% humidity) for 28 days.
3.
Physico-Mechanical Tests:
To assess the heat resistance of concrete, samples were
exposed to three temperature levels – 200°C, 400°C, and 600°C – for 3 hours in a
specialized oven. After cooling, their physico-mechanical properties were evaluated.
Compressive strength was measured using a universal testing machine (maximum load
capacity of 100 kN), density was determined via the gravimetric method, and water
absorption was assessed in accordance with O‘z DSt 3040:2016 standards. Five samples
were used for each test.
4.
Statistical Analysis:
The obtained results were processed using analysis of variance
(ANOVA). The impact of temperature on the physico-mechanical properties of concrete
was evaluated at a 95% confidence level. Differences between samples with and without
additives were analyzed using the Student’s t-test.
5.
Additional Tests:
To examine the microstructure and changes in concrete after heat
exposure, samples were analyzed using an optical microscope.
Results
The research yielded the following specific data on the physico-mechanical properties
of heat-resistant concrete:
1.
Compressive Strength:
Under ambient conditions (20°C), the control group exhibited
an average compressive strength of 38 MPa, while the additive group reached 39 MPa.
At 200°C, the control group’s strength decreased to 34 MPa (10% reduction), and the
additive group’s to 36 MPa (8% reduction). At 400°C, the control group recorded 27
MPa (29% reduction), and the additive group 30 MPa (23% reduction). At 600°C, the
control group dropped to 18 MPa (53% reduction), while the additive group showed 22
MPa (44% reduction). Samples with aluminum oxide and shungite additives proved
more stable at high temperatures.
2.
Density:
Density decreased noticeably with rising temperatures. At ambient conditions,
it was 2400 kg/m³; at 200°C, it fell to 2380 kg/m³; at 400°C, to 2320 kg/m³; and at
600°C, to 2250 kg/m³. This change was attributed to pore formation due to heat
exposure.
3.
Water Absorption:
For samples without additives, water absorption increased from 8%
at ambient conditions to 12% at 600°C. In contrast, samples with additives showed a
range of 7% to 9%, indicating the additives’ effectiveness in reducing porosity.
4.
Statistical Results:
ANOVA confirmed that the effect of temperature on compressive
strength was statistically significant (p < 0.05). The difference between samples with
and without additives was also significant (p < 0.01) based on the t-test. Additives
improved concrete properties by an average of 10-15%.
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 04,2025
Journal:
https://www.academicpublishers.org/journals/index.php/ijai
page 339
5.
Microscopic Analysis:
Post-heat exposure, the control group samples exhibited
numerous microcracks and pores on their surfaces, whereas samples with additives
showed fewer such changes.
Physico-Mechanical Properties Under Temperature Influence
Table 1.
Temperature
(°C)
Compressive Strength
(Control, MPa)
Compressive Strength
(Additive, MPa)
Density
(kg/m³)
Water
Absorption
(%)
20
38
39
2400
8
200
34
36
2380
9
400
27
30
2320
10
600
18
22
2250
12
Differences Between Samples With and Without Additives (600°C)
Table 2.
Property
Control
Group
Additive Group
Difference (%)
Compressive Strength
(MPa)
18
22
+22
Density (kg/m³)
2250
2280
+1.3
Water Absorption (%) 12
9
-25
Discussion
The results confirmed the high effectiveness of the methods used to investigate the physico-
mechanical properties of heat-resistant concrete. Literature analysis indicated that heat-resistant
additives (aluminum oxide, shungite) play a crucial role in enhancing concrete stability, a
conclusion fully supported by the experimental results. For instance, at 600°C, samples with
additives outperformed the control group by 22% in compressive strength. The data on
temperature effects on concrete properties aligned with trends observed in Neville (2011) and
Bazhenov (2015), though slight variations were noted due to compositional differences in local
raw materials (e.g., the chemical quality of cement).
Advantages of the Methods:
Experimental tests enabled precise measurement of temperature effects on concrete
properties, with temperature levels (200°C, 400°C, 600°C) simulating conditions close
to industrial settings.
Statistical analysis provided scientifically reliable results and numerically validated the
efficacy of additives.
The use of local raw materials proved economically beneficial, potentially reducing the
cost of 1 m³ of concrete by approximately 15-20%.
Microscopic analysis offered additional insights into internal structural changes in the
concrete.
Limitations:
Tests were conducted solely under laboratory conditions. Additional verification in real
industrial settings (e.g., under continuous thermal loads) is required.
Long-term heat exposure (e.g., 24 hours or more) was not studied, limiting the
comprehensive assessment of durability.
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 04,2025
Journal:
https://www.academicpublishers.org/journals/index.php/ijai
page 340
Microscopic analysis was limited to surface-level observations, necessitating a scanning
electron microscope (SEM) for deeper analysis.
In Uzbekistan, utilizing local cement and waste materials (e.g., phosphogypsum, slag) offers the
potential to produce affordable and eco-friendly heat-resistant concrete. For example, adding
phosphogypsum could reduce raw material costs by 10%. Future research should expand to
higher temperature regimes (800°C and above), long-term testing, and more in-depth
microscopic analysis. Additionally, pilot projects are recommended to facilitate the industrial
application of this concrete.
Conclusions
The methods applied in this study – literature analysis, experimental testing
methodology, physico-mechanical tests, and statistical analysis – proved effective in
determining and enhancing the behavior of heat-resistant concrete under high-temperature
conditions. Additives such as aluminum oxide and shungite were confirmed to improve
concrete stability by 10-15%. Considering local conditions, this concrete shows strong potential
for use in industrial structures and the construction sector.
The research findings contribute to the adoption of sustainable and cost-effective materials in
Uzbekistan’s construction industry. Leveraging local resources not only reduces costs but also
supports ecological sustainability. The practical significance of this work lies in its potential to
enhance the production and application of heat-resistant concrete in the local market.
References:
1. Neville, A.M. (2011). Properties of Concrete. London: Pearson Education Limited.
2. Bazhenov, Yu.M. (2015). Concrete and Gypsum Concrete Technology. Moscow: Stroyizdat
Publishing.
3. O‘z DSt 3040:2016. General Technical Requirements for Construction Materials. Tashkent:
O‘zStandart.
4. Ahmedov, Sh.M. (2020). “Utilization of Local Raw Materials in the Production of
Construction Materials in Uzbekistan.” Uzbekistan Construction Journal, 5(10), 34-40.
5. ISO 14040:2006. Environmental Management – Life Cycle Assessment – Principles and
Framework. International Organization for Standardization.
