Effect of graphene oxide on mechanical, deformation and drying shrinkage properties of concrete reinforced with fly ash as cementitious material by using RSM modelling

The industrial production of cement contributes significantly to greenhouse gas emissions, making it crucial to address and reduce these emissions by using fly ash (FA) as a potential replacement. Besides, Graphene oxide (GO) was utilized as nanoparticle in concrete to augment its mechanical characteristics, deformation resistance, and drying shrinkage behaviours. However, the researchers used Response Surface Methodology (RSM) to evaluate the compressive strength (CS), tensile strength (TS), flexural strength (FS), modulus of elasticity (ME), and drying shrinkage (DS) of concrete that was mixed with 5-15% FA at a 5% increment, along with 0.05%, 0.065%, and 0.08% of GO as potential nanomaterials. The concrete samples were prepared by using mix proportions of design targeted CS of about 45 MPa at 28 days. From investigational outcomes, the concrete with 10% FA and 0.05% GO exhibited the greatest CS, TS, FS, and ME values of 62 MPa, 4.96 MPa, 6.82 MPa, and 39.37 GPa, on 28 days correspondingly. Besides, a reduction in the DS of concrete was found as the amounts of FA and GO increased. Moreover, the development and validation of response prediction models were conducted utilizing analysis of variance (ANOVA) at a significance level of 95%. The coefficient of determination (R²) values for the models varied from 94 to 99.90%. Research study indicated that including 10% fly ash (FA) as a substitute for cement, when combined with 0.05% GO, in concrete yields the best results. Therefore, this approach is an excellent option for the building sector.