High-strength concrete (HSC) is increasingly utilized in construction due to its superior mechanical properties and durability compared to conventional concrete. Mix designs were enhanced to obtain optimum density and minimum void content by utilizing the Particle Packing Density technique. Over the course of their service life, reinforced concrete (RC) structures may be accidentally loaded by blasts, impacts, or fires, which could lead to the collapse of the structure, resulting in fatalities and financial losses. Concrete’s behavior and properties change significantly when exposed to elevated temperatures. Understanding these changes is crucial for the design, safety, and maintenance of structures exposed to high temperatures. With an emphasis on the compressive strength, tensile strength, flexural strength, and shear strength of HSC, this work offers a thorough experimental and analytical analysis of its behavior. Standard-sized cubes and cylinders were cast and tested at temperatures ranging from 100 to 600 degrees Celsius. The specimens with a strength grade of M75 preserved their compressive strengths at 83.78%, 64.86% and 51.35%, respectively, after the furnace’s temperature reached 200 °C, 400 °C, and 600 °C. Similarly, the splitting tensile strength was retained at 67.93%, 55.35%, and 44.02%, respectively, while the flexural strength was retained at 90.69%, 72.09%, and 62.79%, following the furnace’s temperature reaching 200 °C, 400 °C, and 600 °C. The shear strength of concrete was retained at 89.23%, 75.38% and 66.15%after the furnace’s temperature reached 200 °C, 400 °C and 600 °C, respectively. The insights gained from both experimental and analytical approaches underscore the potential of HSC in enhancing the longevity and resilience of infrastructure through optimized particle packing density and improved thermal performance.
