Influence of ferrochrome slag as coarse and fine aggregates on thermal and strength properties of concrete at high temperatures

Ferrochrome slag (FCS) as aggregates in concrete provides a sustainable alternative for the construction industry due to its admirable mechanical, durability, and refractory properties. These characteristics of FCS may aid in increasing the strength and durability aspects of the concrete. However, when subjected to high temperatures, the characteristics of concrete incorporating FCS aggregates are not well understood. Therefore, the study examined the effects of replacing natural coarse and fine aggregates with FCS aggregates on the thermal and strength properties of concrete, as well as the resistance of FCS concrete to high temperatures. Along with the reference conventional concrete mixture, four other concrete mixtures were produced using FCS fine and coarse aggregates at replacement percentages of 25%, 50%, 75% and 100% of natural stone aggregates. The residual mechanical properties, mass loss, ultrasonic pulse velocity, and change in different physical properties of the concrete mixtures were tested before and after experience to high temperatures between 200 °C and 1000 °C. The experimental data is also used to derive the relationship between temperature and strength reduction factors for FCS concrete. The inclusion of FCS aggregates was found to maintain relatively higher mechanical properties and less mass loss in the concrete after heat treatment. The thermal characteristics of FCS play an important role in enhancing the high-temperature performance of concrete with FCS aggregates.