Optimized components ratio model development for hollow sandcrete block production using mixed aggregate

The The paper investigates the model development and optimization of the components ratio for the optimal compressive strength of 60/40 sand/quarry dust hollow sandcrete block. Quarry dust is a massive waste in quarry sites and can be combined with sand at studied ratios. The study applies the Scheffe's optimization approach to obtain a mathematically experimental model of the form f(x_i1, x_i2, x_i3, x_i4), where x_i are proportions of the concrete components, viz: cement, sand, quarry dust and water. Scheffe's experimental design techniques are followed to mould various hollow block samples measuring 450mm x 225mm x 150mm and tested for 28 days strength. The task involved experimentation and design, applying the second order polynomial characterization process of the simplex lattice method. The model adequacy is checked using the control factors. Finally a software is prepared to handle the design computation process to take the desired property of the mix, and generate the optimal mix ratios.