Optimization of Mix Design of Thermally Efficient Blocks Using the Process Parameter Approach

The development of thermally efficient blocks as wall material to provide a reduction in the heating/cooling load of a building envelope has been investigated by a host of researchers. This paper focuses on the mix design of thermally efficient blocks by using a well-known optimization technique. The method is used to optimize the proportion of the raw materials, i.e., glass powder (GP), palm-oil fly ash (POFA), and oil-palm fibers (OPFs) to achieve minimal thermal conductivity values. Mix proportions were designed as per an orthogonal array with three factors and four levels. Experimental investigations, such as bulk density, water absorption, compressive strength, and thermal conductivity, were conducted. Effects on thermal conductivity caused by control factors were analyzed using signal-to-noise (S/N) ratios and analysis of variance (ANOVA) techniques. The analysis provides percentage contribution of individual control factors and the identification of significant parameters contributing to thermal performance. Furthermore, thermal conductivity values were estimated on the basis of the optimal performance levels of parameters. Last, for validation of the optimized results, experiments on thermal conductivity were conducted alongside the primary essential standard properties of density, water absorption, and compressive strength.