Experimental Investigation on Ultra-Thin White Topping Using Fly Ash-Based Geopolymer Concrete- A Review

The increasing deterioration of flexible pavements due to heavy traffic loading and environmental effects has necessitated the development of efficient rehabilitation techniques. Ultra-Thin White Topping (UTWT) has emerged as an effective solution for improving pavement performance with reduced material consumption and cost. Simultaneously, the environmental concerns associated with Ordinary Portland Cement (OPC), particularly its high carbon emissions, have led to the development of sustainable alternatives such as fly ash-based geopolymer concrete (GPC). This paper presents a comprehensive review of existing studies on UTWT and geopolymer concrete, focusing on their mechanical properties, durability, bonding behavior, and sustainability aspects. Based on the review of more than 30 research studies, it is observed that geopolymer concrete exhibits superior strength, durability, and environmental benefits compared to conventional concrete. However, limited research has been conducted on its application in UTWT systems. This study identifies key research gaps and highlights the need for further investigation into the feasibility of using geopolymer concrete in ultra-thin white topping applications for sustainable pavement rehabilitation.