Thermodynamic Analysis in the Microscopic Structural Characterization of Civil Engineering Materials

Concrete, as the most widely used construction material in civil engineering, plays a crucial role in the durability and safety of structures.In recent years, with the deepening understanding of concrete's microstructure, researchers have begun to explore the intrinsic relationship between its microfeatures and mechanical properties.However, existing characterization methods largely focus on analyzing the mechanical behavior of concrete from a macroscopic perspective, lacking a comprehensive and quantitative description of its microstructure.Traditional experimental techniques such as Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) can reveal the microscopic morphology of concrete but are still unable to precisely analyze the quantitative relationship between the pore structure of concrete and its mechanical performance.Thermodynamic analysis, as a tool capable of effectively revealing the internal physical properties and mechanical behavior of materials, provides a new approach for the characterization of concrete's microstructure.This study primarily explores the relationship between concrete's microstructure and mechanical properties based on thermodynamic principles.Firstly, a thermodynamics-based fractal model for civil engineering concrete is proposed, where the pore structure and fractal features of concrete are analyzed from a thermodynamic perspective to further uncover the regularities of its mechanical behavior.Secondly, the study investigates the relationship between compressive strength and pore structure of concrete under high-temperature conditions, analyzing the effects of high temperatures on the evolution of concrete's pore structure and its mechanical performance.Through these studies, this paper not only introduces new analytical methods for the microstructural characterization of concrete materials but also provides a theoretical foundation for the performance prediction and optimized design of concrete in high-temperature environments.