Unlocking the insightful performances of metakaolin and ferrochrome slag sand mortar at elevated core temperatures

The evolution of infrastructural development demands using innovative and eco-friendly materials in construction. The net-zero of carbon emission and waste management are booming areas of research. This pivotal work involves reducing decarbonisation by reducing clinker usage and waste management by replacing slag with fine aggregate. The metakaolin of 7, 9, 11, and 13% of weight are investigated as cement replacement. Supplementary Cementitious Material (SCM) concludes that metakaolin of 11% (M3 mix) performs better in mechanical strength. In the M3 mix, the crushed sand (C-sand) is replaced by Ferrochrome slag sand (FeCr-Sg) of 25, 30, 35, 40, and 45% weight. The compressive strength and UPV of the MFS4 mix (40% of FeCr-Sg) are superior at room temperature. The Core temperature of M0, M3, and MFS4 mix is subjected to heat for 2 h at 150^◦C, 300^◦C, 450^◦C and 600^◦C respectively. The strength, water absorption and UPV of MFS4 mix at room temperature perform better. The relative mass loss at 600^◦C in MFS4 is 93.2%. The MFS4 mix attains a dense microstructure, zero crack surface texture and better passing of pulse velocity rather than M0 and M3 at 600^◦C. Metakaolin with FeCr-Sg was effective in enhancing mechanical, durability and thermal properties in both ambient and elevated temperature matrix.