Non-Destructive Assessment of Heated Rc Columns Cooled by Two Cooling Methods

Abstract

Fire constitutes a major hazard to the buildings. The structural members exposed to high temperatures during fire accidents. The phenomenon observed was the structural members undergo dehydration of concrete, thermal distress in the form of cracking and spalling due to excessive heating. This leads to cause degradation of concrete strength. After tackle the fire hazard, the next step is to find the suitability of the building for repair or restoration, which involves assessment of fire severity and fire damage. Nondestructive testing (NDT) is the most practical and widely used methods to obtain in place strength or even for new structure strength. It is an effective tool for damage assessment and quality assurance, as well. In this paper, reinforced concrete (RC) columns made with OPC mix and HVFA mix, exposed to high temperatures ranging from 100 to 800°C. After heating, the specimens were brought to room temperature by air cooling and water quenching methods. The specimens were tested for residual compressive strengths and material integrity of concrete columns, by non-destructive testing methods, to understand how parameters like cooling condition and exposure duration influence the mechanical properties of conventional concrete mix and fly ash concrete mix. OPC concrete mix columns performed better strengths over HVFA mix columns when they cooled by air. Whereas water quenched HVFA mix columns upkeep the concrete quality grading on comparing the OPC mix specimens.