Review of Geopolymer Composites Synthesized Using Different Industrial By-products

Abstract

Managing the substantial volume of industrial waste is challenging due to diminishing landfill capacity and associated risks to people and the environment. The optimal approach is to repurpose or find alternative applications for these waste products. Previous studies have investigated using industrial waste and chemicals to enhance soil stability. Common binders like cement, while offering significant stabilization potential, raise concerns about economic feasibility and environmental impact. Recently, there’s a growing interest in low carbon emission cementing agents. This trend leads to using waste by-products for geopolymer binder production, potentially strengthening soft soil in an eco-friendly way. Unconfined compressive strength, vital in construction foundation design, has been a focus of extensive research to enhance soil strength over the years. This paper provides a brief overview of several studies that highlight the utilization of various industrial waste products in the synthesis of geopolymers. Also, this comprehensive review centers on investigations related to the application of geopolymers derived from industrial solid waste as a soil stabilizer. The review delves into the impact of various parameters, including different percentage mixes (%), molarity (M), temperature (T), curing time (days), on the unconfined compressive strength of the soil. It has been observed that, a variety of industrial by-products like Bagasse ash (BA), Blast furnace slag (BFS), Egg shell powder (ESP), Fly ash (FA), Ground Granulated Blast Furnace Slag (GGBS), Iron Ore Tailings (IOT), Metakaolin (MK), Palm Oil Fuel Ash (POFA), Recycled Asphalt Pavement (RAP), Rice husk ash (RHA), Red Mud (RM), etc. can serve as valuable source materials for geopolymerization. In most of the studies, the commonly utilized alkaline activator consists of a blend of sodium hydroxide and sodium silicate solution. The unconfined compressive strength of geopolymerized industrial waste products relies on specific parameters, including optimal alkaline concentration, activator liquid to raw material mass ratio, and sodium silicate to sodium hydroxide solution ratio. Diverse curing conditions are also necessary, varying with raw materials and activators.