Study on the Behavioral Response of Concrete to Prolonged Exposure to Elevated Temperatures

This study investigates the residual strength of High Strength Concrete (HSC) made with Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC) when subjected to elevated temperatures, ranging from 50°C to 250°C for durations of 1, 2, and 3 hours. Concrete, extensively used in high-rise buildings, industrial facilities, and critical infrastructure, is vulnerable to cracking, spalling, and structural damage when exposed to high temperatures, leading to significant financial losses. This research focuses on understanding how HSC, which includes additives like micro silica and pulverized fuel ash, performs under thermal stress, particularly in environments like nuclear reactors and petrochemical tanks. The study explores the effects of temperature exposure on compressive, split tensile, and flexural strength, comparing the properties of concrete exposed to heat with those of room-temperature concrete. One major challenge in high-temperature exposure is the thermal mismatch between concrete’s surface and core, leading to internal stress and cracking. The dehydration of calcium silicate hydrate (C-SH) gel in the cement paste results in shrinkage, reduced binding strength, and eventual failure. The findings provide critical insights into the thermal durability of HSC, offering guidelines for its use in high-temperature environments and ensuring structural integrity under extreme conditions.