Phân tích ảnh hưởng của sự sinh nhiệt từ quá trình thủy hóa xi măng lên bê tông khối lớn bằng phương pháp phần tử hữu hạn

Mass concrete structures, essential in large-scale infrastructure like dams and high-rise building foundations, are inherently susceptible to thermal cracking. This phenomenon primarily arises from the significant heat generated during cement hydration, leading to substantial temperature differentials between the concrete core and its surface. Such differences induce considerable tensile stresses that can exceed the material's tensile strength, compromising the structural integrity and long-term durability of the construction. Addressing this critical issue, this study employs the Finite Element Method (FEM) to thoroughly analyze the impact of hydration heat on mass concrete, aiming to provide crucial insights into temperature evolution and thermal cracking risks. The objective is to assist engineers in optimizing mix designs, construction methodologies, and thermal control strategies for these vital projects.

Civil engineers, structural engineers, construction managers, and researchers involved in the design and construction of large-scale concrete infrastructure projects.

This research provides a comprehensive analysis of the effects of cement hydration heat on mass concrete structures, focusing on the critical issue of thermal cracking. The study employs the Finite Element Method (FEM) to develop a sophisticated numerical model that simulates the intricate heat transfer process within mass concrete. This model meticulously incorporates key parameters such as hydration heat generation, thermal conductivity, and various boundary conditions, solving the governing heat transfer equation using an implicit time-stepping scheme (generalized trapezoidal rule). Subsequently, the distribution of thermal stress is evaluated to assess the risk of cracking, utilizing established thermal crack indices. Key findings reveal that mass concrete structures experience significant temperature increases in their core due to hydration heat, while the surface is considerably influenced by ambient environmental conditions. This temperature gradient generates substantial tensile stresses, particularly near the surface, and compressive stresses in the core. The study demonstrates that increased concrete layer thickness intensifies peak temperatures, prolongs cooling periods, and heightens the probability of thermal cracking. For instance, layers exceeding 2 meters exhibit a high probability of crack formation (23% at 2m, over 50% at 2.5m and above), underscoring the necessity for stringent temperature control. The implications of this research are substantial for large-scale concrete projects. The insights gained enable engineers to optimize concrete mix designs, refine construction procedures, and implement effective cooling strategies. This includes selecting appropriate layer thicknesses and thermal insulation methods to mitigate thermal cracking risks, thereby enhancing the quality, durability, and service life of structures like dams, bridge foundations, and major building foundations.