Application of glass in subsurface pavement layers: A comprehensive review

Glass-based goods are produced and consumed in relative abundance, making glass a material that is found in most households, thereby leading to its accumulation in alarming quantities throughout the globe and posing an environmental challenge. This being said, glass has been widely acknowledged to possess a variety of desirable physiochemical properties, making it suitable for utilisation as an engineering aggregate. The properties include its non-biodegradable nature, resistance to chemical attack, low water absorption, hydraulic conductivity, temperature-dependent ductility, alterable particle gradation, and its availability in a multitude of forms/chemical compositions. Owing to these properties, glass has been employed in a myriad of civil engineering studies and field trials to assess its efficacy as an engineering aggregate and to provide sustainable management schemes for waste glass. These studies/trials have incorporated glass in many forms, including fine recycled glass (FRG), medium recycled glass (MRG), coarse recycled glass (CRG), glass powder, glass fibres, foamed glass, and glass-based geopolymers. Although the beneficial properties of glass can be exploited in numerous engineering endeavours, this review paper focuses on the possible application of glass to subsurface layers of pavements. In turn, the current study centres on research studies/trials presenting results on the physicochemical, mechanical, and durability aspects of pavement layers (base, subbase, and subgrade) containing pure glass samples or glass as percentage replacements in materials, including but not limited to unbound granular materials (i.e., recycled concrete aggregate (RCA) and crushed rock (CR)) and clay soils. Through the knowledge compiled in this review article, it is reasonable to state that glass shows solid potential as a road pavement material.