Multi Objective Optimization of Mix Proportion for a Sustainable Construction Material

The rapid industrialization and urbanization resulted in large quantity of waste generation and in turn, environmental degradation. Recycling of solid waste into a sustainable construction material with optimum mix proportion is the global need to reduce its adverse environmental impacts. The present paper aimed at optimization of the mix proportion for designing the sustainable material. Sugarcane bagasse ash (SBA) was identified as the principal raw material over the study area. It was used further in combination with quarry dust (QD), and lime (L) for various proportions to develop the sustainable bricks. In all 35 compositions for SBA-QD-L bricks were developed and Physico-mechanical properties were evaluated using standard laboratory tests as per Indian standards. A statistical cubical regression model was formulated for compressive strength of brick as a function of mix proportion using XLSTAT software. To achieve the criteria of sustainability, constraints were developed in terms of achieving maximum compressive strength and minimum embodied energy. A multi objective non-linear optimization model was formulated and optimum mix proportion was obtained using software LINGO. The optimum value of compressive strength and embodied energy predicted by this model was 5.44 MPa and 2.32 MJ. The embodied energy was estimated to be 47% and 5% lower than the conventional burnt clay and fly ash bricks. A cost analysis was also carried out between optimum composition of SBA-QD-L bricks and commercially available fly ash bricks. The percentage reduction in the cost was found to be 49% and 58% as compared to the fly ash and burnt clay bricks.