Material Durability Theory: Civil engineering structures rely heavily on the durability of materials used. Develop a comprehensive theoretical framework discussing the factors influencing material durability in civil engineering projects. Consider aspects such as environmental exposure, chemical reactions, mechanical stresses, and long$-$term degradation mechanisms. Additionally, explore the role of material composition, manufacturing processes, and quality control measures in ensuring longevity and resilience against various forms of deterioration. Provide insights into how this theoretical understanding can inform material selection, maintenance strategies, and the design of sustainable infrastructure.