Optimizing geopolymer-based material for industrial application with analytic hierarchy process and multi-response surface analysis

Copyright © 2015, AIDIC Servizi S.r.l.,. High CO2 emission and energy intensity from the Portland cement industry has prompted many researchers to develop cleaner and low-emission technologies for a sustainable built environment. Geopolymer technology is one promising solution to produce an alternative cementitious material with lower carbon footprint, and reduce the global consumption of Portland cement. Geopolymer can use waste such as red mud, coal ash, rice hull ash, among others, as raw materials for reactive alumina-silicates. At high alkaline condition, these alumina-silicates form a geopolymer cement binder system that hardens at room temperature like Portland cement. However, optimal mix formulation of these raw materials is necessary to produce materials with desired specification for a specific application. This work thus presents a systematic method that integrates the statistical design of experiment, multiple response optimization technique and analytic hierarchy process for product design of geopolymer-based materials. The method is demonstrated using a case study involving a geopolymer from a ternary blend of red mud, rice hull ash, and diatomaceous earth. Aside from the mechanical and thermal properties, production cost, embodied energy and carbon footprint were considered in modeling the product desirability