Abstract
This study aimed to establish the optimal mix proportions for eco-friendly lightweight boards based on Ground Granulated Blast-furnace Slag (GGBFS) and waste rock wool using Response Surface Methodology (RSM). The investigation focused on optimizing three key properties: flexural failure load (Y(1)), moisture content (Y(2)), and specific gravity (Y(3)). ANOVA results identified Binder and Perlite as the most dominant and statistically significant factors, exhibiting critical conflicting effects necessary for balancing strength and lightweight goals. Wollastonite showed a non-linear effect on flexural strength, peaking at an intermediate level. A Response Optimization simulation, targeting a minimum flexural load of 400 N, moisture content of 2.0%, and specific gravity of 0.80, yielded an optimal mix proportion: Binder 52.12%, Perlite 48.45%, and Wollastonite 7.37%. This blend achieved a high Composite Desirability (D) of 0.8725. Experimental verification confirmed the model's reliability. The measured flexural load (408.54 N) successfully exceeded the 400 N target, and all measured values exhibited a low error margin (under 7%) compared to the predicted values. This optimized mix proportion provides a reliable foundation for developing high-performance, sustainable lightweight construction materials.