Influence of thermal damage on chloride penetration in concrete: Experimental and theoretical modeling

This study investigates the effect of thermal damage on chloride penetration in concrete by analyzing experimental data obtained from 70 cylindrical and prismatic samples with compressive strengths of 34 and 43 MPa. The samples were subjected to elevated temperatures (200, 350, 500, and 650°C) for two hours, and the extent of thermal damage was assessed using ultrasonic pulse velocity (UPV) measurements. Following exposure to a saline. Results indicated that thermal exposure significantly accelerates chloride ingress, with chloride penetration depth increasing by up to 45% in samples exposed to 650°C compared to control specimens. This was attributed to increased cracking, resulting in greater pore connectivity and facilitating easier chloride ion movement. In order to measure chloride penetration into heat-damaged concrete, a predictive model was created that took into account how damage severity affects diffusion behavior. Experimental data was used to validate the model, which showed a strong agreement with measured chloride profiles. The findings highlight the significant impact of heat exposure on concrete's resistance to chloride ingress, emphasizing the need for further research on additional environmental factors such as relative humidity and material composition to enhance durability predictions in fire-affected structures.