Performance and microstructure of concrete containing green and LCD glass sand as fine aggregates

Abstract Rapid urbanization and environmental regulations have led to a shortage of natural river sand, prompting the use of alternative aggregates. This study evaluates green waste glass and liquid crystal display (LCD) glass sand as partial substitutes for manufactured sand (MS) in concrete. Comprehensive tests assessed mechanical properties (compressive and flexural strength), durability (drying shrinkage, impermeability, sulfate resistance), and alkali–silica reaction (ASR) potential. Microstructural evolution was analyzed using mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and electrical resistivity. Results demonstrate that a 20% green glass substitution (GG20) achieved optimal performance, with 28-day compressive and flexural strengths of 51.8 MPa and 6.1 MPa, respectively. Both glass types significantly reduced drying shrinkage and enhanced sulfate resistance by refining pores. Despite increased ASR activity in the LCD group, pozzolanic reactions and the micro-filling effect densified the paste matrix. This research validates specialized waste glass as a sustainable performance enhancer for manufactured sand concrete, offering a robust theoretical foundation for eco-friendly construction.