Influence of graphene oxide and fly ash on the thermal and structural performance of concrete slabs

In this study, fly ash (FA)-and graphene oxide (GO)-modified reinforced concrete (RC) slabs were examined for their mechanical characteristics, durability, and microstructural behavior at high temperatures. The use of cutting-edge and sustainable materials is the main goal for improving the fire resistance and strength retention of RC structures. Four concrete mixtures were combined 20% fly ash (by weight of cement) and 0.08% graphene oxide (by weight of cement) used in the experimental investigation. Along with the RC slabs (590 mm × 100 mm), standard cube, cylinder, and prism specimens were cast and tested at room temperature and after exposure to 200 °C, 400 °C, 600 °C, and 800 °C. The results of the experiment showed that the FA + GO hybrid mix performed better mechanically. Its compressive strength of 43.8 MPa at room temperature represented a 23.7% increase in compressive strength corresponds to the 28-day compressive strength test. It was maintained at 28–84 MPa, even after exposure to 800 °C, indicating a strength loss of 47%. This was much less than the 58.57% loss in the conventional specimens. Microstructural studies (XRD and FTIR) confirmed the presence of stable hydration products and formation of a dense matrix. These findings confirm the efficacy of FA and GO in enhancing the high-temperature performance of RC structures.