Abstract

Lightweight aggregate concrete (LWAC), produced by partially or fully replacing conventional dense aggregates with lightweight alternatives, is increasingly used in structural and building applications. Lightweight Expanded Clay Aggregate, or LECA, is a common kind of lightweight aggregate. However, due to its inherent disadvantages that include high water absorption caused by its porous structure, low mechanical strength, and high brittleness, its use in structural concrete is limited. Surface treatment of LECA has emerged as a promising strategy to improve its mechanical performance and durability, in order to overcome these limitations. Coating LECA with geopolymer-based materials made from solid waste and industrial waste that is high in aluminosilicates. These geopolymer systems can penetrate and seal the surface pores of LECA when activated by alkaline solutions to create a durable protective barrier that improves the structural integrity of the aggregate. Thus, this paper reviews the key parameters influencing the geopolymerization process including the composition and nature of the raw material, alkaline activator molarity, solid-to-liquid ratio, and curing conditions. In order to formulate long-lasting, high-strength geopolymer coatings for LECA and, subsequently, expand the use of the material in load-bearing and green structures, a comprehensive understanding of these factors is essential.