Post-heating strength prediction in concrete with Wadi Gyada Alkharj fine aggregate using thermal conductivity and ultrasonic pulse velocity

The continuous demand for economical high-performance thermally resilient concrete with superior mechanical behavior is pivotal for sustainable concrete infrastructure. Few studies have examined the effect of the frictional resistance of fine aggregates on the thermal resilience of concrete structures. Laboratory tests (compressive strength, thermal conductivity, and ultrasonic pulse velocity tests) were conducted to evaluate the thermal resilience of the fine aggregates. The results showed that 20 % optimal partial replacement of traditional aggregate by Wadi Gyada Alkharj Fine Aggregate (WGAFA) enhanced compressive strength (CS), thermal conductivity (TC), and ultrasonic pulse velocity (UPV) by 19 %, 23.8 %, and 36.5 %, respectively, compared to traditional aggregate. The results showed that TC, CS, and UPV declined by 58 %, 49 %, and 47 %, respectively, after exposure to the 800 °C thermal effect versus that at 25 °C. A predictive model for post-heating compressive strength (CS) was proposed for fire-resistant infrastructures to prevent loss of life and reduce financial losses from infrastructure destruction. This study demonstrated that non-destructive test parameters can effectively evaluate the post-heating residual compressive strength of fire-affected concrete structures for future use.