A Review of Geopolymers-Based Artificial Aggregates Technology Developed Using Waste Materials

Abstract

Scholars around the world are concerned with the continuous reduction of aggregates-related natural resources globally. This led to recent studies on the importance of reusing and recycling waste generated from biological materials and industry by-products. The interest in the exploration of waste was due to the increase in the demand for aggregates normally used as a major component in producing concrete. With the continuous development of technology, the stock of natural aggregates on Earth is declining, hence, an alternative is required to replace natural aggregates. Geopolymer artificial aggregates are aggregates made by several methods such as sintering, autoclaving, and cold bonding with alumino-silicate precursors obtained from waste materials such as metakaolin, slag, red mud, fly ash, and calcined kaolin sludge which are activated using an activator. The activated precursor using this activator causes a polycondensation process called geopolymerization. Geopolymers system was discovered to have remarkable attributes such as exceptional force, enhanced endurance, and heightened fire tolerance, which can be a compelling substitute for aggregates in Ordinary Portland Cement (OPC) concrete. Therefore, this study explores and collects various studies related to the methods used to produce geopolymer-based aggregates and their characterization. The focus is on the production of these produced aggregates, and appropriate approaches are established to improve the quality of the aggregates produced, accompanied by insightful suggestions for future investigations.