Methods for Investigating the Physico-Mechanical Properties of Heat-Resistant Concrete

Аннотация

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 theconstruction 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 methodsis ofcritical 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, thelack of precise data on the behavior and changes in the physico-mechanical properties of concrete underhigh-temperature conditionsfurther underscores therelevance of thisresearch. 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 ofheat-resistant concrete. Thesemethods are detailed below: page337 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue04,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai 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 inUzbekistan 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 understandard conditions (20°C,95%humidity) for28days. 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 concre