Geopolymer Innovation in Construction: Environmentally Friendly and Sustainable Materials

Abstract

Geopolymer bricks are a crucial innovation in the construction industry, representing an environmentally friendly and sustainable approach. The primary ingredients are sourced from industrial waste, including copper mine tailings and iron ore, which are often considered environmental pollutants. The production process of geopolymer bricks involves the use of chemicals, such as sodium silicate and sodium hydroxide (NaOH), as activators to form polymeric bonds. Additionally, various other industrial wastes, such as ceramic waste, clay bricks, and plastic waste, are used as formulation ingredients to minimize environmental impact. The addition of supplementary ingredients, including metakaolin, Ground Granular Blast Furnace Slag (GGBFS), Recycled Concrete Aggregate (RCA), Foundry Sand Waste (FSW), slag sand, and fly ash, further supports the development of unique properties in geopolymer bricks. Geopolymer brick production methods encompass various techniques, including extrusion, standardization, and high compaction up to 100 MPa. The firing process in an electric furnace is a crucial step in forming and firing bricks with optimal strength and durability. During the production stage, polypropylene fibers and binding geopolymers, such as sodium, calcium, and ammonium, are used to increase the cohesion and durability of geopolymer bricks. It is essential to pay attention to the water absorption properties of geopolymer bricks, as this affects the performance and durability of structures built using this material. Water absorption may vary depending on the ingredient formulation and production process. Several factors that influence water absorption include curing time, slag content, percentage of aggregate replacement, and the use of polypropylene and metakaolin fibers. The typical water absorption limit for geopolymer bricks should not exceed 20% of the brick's weight, with an acceptable initial absorption range of 10-30 grams. The physico-mechanical properties of geopolymer bricks are also the focus of research. The compressive strength of geopolymer bricks is one of the important parameters that must be considered. Compressive strength ranges from 5-60 N/mm2, and in some cases, even higher, meeting standard requirements. Factors influencing the strength of geopolymer bricks include the ratio of grog and ceramic waste, alkali content, percentage of aggregate replacement with Recycled Concrete Aggregates (RCA) and Polyethylene Terephthalate (PET), and production processes, such as rapid firing and hypercompaction. In addition, the use of lignosulfonates and other additives, such as marble dust powder (MP) and limestone dust powder (LP), can also affect the physico-mechanical properties of geopolymer bricks. The use of chemical additives and stabilization plays an important role in increasing the strength and durability of geopolymer bricks. Chemical stabilization using cement, lime, or other binders can significantly increase the durability of bricks. Apart from that, research also highlights the use of nanotechnology as a stabilizer to increase the durability of brick materials.