Study of the properties of self-compacting concrete incorporating various cementitious powder components using response surface methodology and optimization technique

• Multi-component cementitious powder system modeled via RSM • Quantification of nonlinear powder–admixture interactions • D-Optimal design reduces experimental effort efficiently • High predictive accuracy (R² > 0.95) without lack-of-fit • Multi-objective optimization of rheology–strength balance The performance of highly concentrated cementitious suspensions is governed by complex relationships between fine powder constituents and chemical admixtures. This study proposes a multi-objective Response Surface Methodology (RSM) framework to model and optimize a multi-component cementitious system comprising cement, limestone filler, silica fume, superplasticizer, and viscosity-modifying agent. A D-optimal experimental design was implemented to investigate the influence of superplasticizer dosage (0.30–1.00%), viscosity-modifying agent content (0–0.40%), limestone filler (0–40%), and silica fume (0–30%), while maintaining constant base powder and water contents. Fresh-state properties, including slump flow, V-funnel flow time, L-box ratio, and segregation resistance, were used to characterize flowability, viscosity-related behavior, and stability, whereas 28-day compressive strength was used to evaluate mechanical performance. Quadratic response surface models were developed and statistically validated, demonstrating high predictive capability (R² > 0.95) with no significant lack-of-fit. The results show that SCC performance is predominantly governed by the individual contributions of mixture components and nonlinear (quadratic) effects, with no statistically significant interaction terms identified within the investigated domain. Multi-response optimization using a desirability function enabled the identification of an optimal mixture that achieves a balanced performance in terms of flowability, stability, and compressive strength. These findings highlight the dominant role of independent factor effects in SCC behavior under constrained experimental conditions. The proposed framework provides a robust and efficient approach for SCC mix design and contributes to a clearer understanding of the mechanisms controlling rheological and mechanical behavior in multi-component cementitious systems.