Evaluation of Geopolymer Composites, Based on Red Mud and Metakaolin, for Building Application

Portland cement is widely used in civil construction, although its production involves the emission of high amounts of carbon dioxide. Geopolymers have been studied as an alternative to replace Portland Cement. These materials can be produced using wastes and they are less aggressive to the environment. The aim of this work was the physical and mechanical evaluation of geopolymers composites based on red mud and metakaolin as precursors and sodium hydroxide (NaOH) as activator. Compressive strength tests were performed in ten mixtures with different percentages of the precursors and sand. The water absorption index and microstructural analysis were also determined. Furthermore, durability tests were performed on the composites, in order to allow complete characterization and suggestions of applicability in civil construction. The results showed that the composites have physical and mechanical characteristics that comply with the standards and good durability performance. Therefore, they can be used to produce construction bricks.