Utilisation of construction and demolition waste and recycled glass for sustainable flexible pavements: A critical review

Abstract

The heightened pressure on natural resources, coupled with unprecedented levels of waste and pollution, has created an urgent need for sustainable construction practices in the road industry. To this end, the use of recycled aggregates in pavement construction has gained significant attention due to their environmental, economic, and social benefits. However, despite their immense potential, the application of recycled materials in flexible pavements remains limited due to concerns over their long-term performance, variability in properties, environmental impacts and inconsistent specifications. This article provides a critical analysis of the current state of knowledge on the use of recycled aggregates, particularly recycled concrete aggregate (RCA), recycled crushed brick (RCB) and recycled crushed glass (RCG), for sustainable flexible pavement construction. By examining key laboratory and field investigations, this study evaluates the physical and mechanical characteristics of recycled materials and their blends and assess their suitability for use in pavements. While previous studies have demonstrated that recycled aggregates can be effectively used in pavements, their performance is influenced by factors, such as source, composition, gradation, age, degree of compaction, moisture content, and loading conditions. This study also assesses the suitability of predictive models in evaluating the resilient modulus and cumulative permanent deformation of recycled aggregates and their blends under cyclic loading, which could be used in the design of flexible pavements incorporating these materials. The main objective of this review is to promote wider adoption of aggregates derived from construction and demolition waste, as well as waste glass, in flexible pavements.